Tour to Neocene
|
||||||||||||
This chapter is based on idea of Timothy Donald Morris.
Human epoch was a time of erasing of borders between phyto-
and zoogeographical realms. Human activity allowed one or another species of
live organisms to cross continents and oceans, overcoming natural obstacles
to settling, and rendered thus enormous influence on fauna and flora of various
areas of the Earth. In various places of the planets instantly to measures of
evolution new species appeared, changing directly or indirectly conditions of
life of kinds evolved in strictly different conditions for millions years. One
of such kinds settled was the human species itself, and other kinds settled
by people represented trade and commercially important species, pets or simply
a tribute to whims and follies of intelligent species. After human disappearance
not all species introduced by people have died out. Some of them have continued
to prosper even without human protection, and their existence changed character
of evolution of live organisms cooperated with them directly or indirectly.
Results of the changes initiated by people are especially clearly appreciable
many millions years after their extinction in places which nature has most strongly
suffered from their activity. One of such places is New Zealand, the archipelago
isolated from other land bodies by ocean spaces.
The geography of New Zealand has changed only a little from human epoch. Islands
practically did not become closer to any continent, and no new islets which
could serve as a “bridge” between archipelago and the nearest land appeared
near to them.
Snow-covered mountain peaks are reflected in waters of the lake stretched in
valley at the Southern Island. The landscape is very picturesque: the valley
is surrounded by mountain ridges overgrown with forests, and the highest tops
are covered with dazzling white snow. Lake shores are strewn with stones, among
which there are some boulders of fair sizes covered with moss and overgrown
with lichens of various color and texture. Lake shores are also grown with forest
made mainly of coniferous trees. Here majestic kauris, representatives of native
flora, still exist, however the significant part of forest is formed by pines,
the descendants of the human-introduced plants. Kauri crones tower above the
canopy of pine wood and grow lonely or in small groups. From time to time storms
bring down centuries-old green giants, and they crush under themselves and break
pines, giving open space for growth of bushes and deciduous trees. Deciduous
trees also expand in places where ground is too moist for pines – near marshes
and along the coast of water bodies. In underbrush ferns of various kinds prosper,
undemanding to sunlight, and trunks of trees are covered with a carpet of mosses
and lichens. Here and there on trunks the ferns expand also, seized with roots
in their bark. Also in underbrush groups of treelike ferns grow – these are
relicts of past times.
In the Southern hemisphere there comes spring, and changes are felt everywhere
in nature of islands. In mountains snow begins thawing gradually, and the rivers
running into lake become deeper, rough and wide. Change of length of light day
and a chemical compound of water is felt by lake inhabitants – there comes the
time to procreate and their behaviour changes gradually.
Forests of islands are full of life. Even if wood inhabitants cannot be seen,
it is easy to guess their presence: from forest to lake shore many tracks lead,
worn by large animals.
Terrestrial fauna of islands has strongly suffered from human activity in historical
time. In the past its basis was made of various ground-dwelling flightless birds.
People have exterminated birds and after that have introduced to the islands
the set of various mammals, which make a basis of terrestrial fauna of large
animals at the continents. And in Neocene in fauna of islands ungulates, lagomorphs,
rodents, marsupials and carnivores dominate – all of them are descendants of
the species introduced by people. The features of island fauna has changed forever
and only in some places at coastal islets not numerous descendants of native
fauna of islands still survive.
The introduced animals have found favorable conditions for life in New Zealand.
The climate of islands never was too cold, even if glaciers at tops of mountains
expanded and moved downwards the slopes. Influence of ocean strongly softened
it in glacial epoch of the boundary of Holocene and Neocene, and in warm Neocene
still makes climate more equal and humid, smoothing a difference of temperatures
in various seasons. Snow in valleys and at coasts does not drop out even in
the middle of winter, but the change of the season is felt all the same: in
winter weather is a little bit damper and colder, and days are appreciably shorter.
But winter is already finished, and the sun stays in the sky for longer and
longer and all rises higher for every new day. Spring gradually enters the rights
though winter weather still makes the revenge at night. In the cool morning
on leaves and grass there is plentiful dew. Slight breeze swings branches of
trees, and dew falls from them on wool of large animal walking along the track
to lake shore. The large deer – buck of New Zealand ultradama
– comes to water. It is one of the most impressing kinds of New Zealand fauna
of Neocene epoch – an animal of the size of large horse, but built more gracefully.
Buck has reddish-brown wool without spots which it has left in due course of
maturing, though its ancestor was a fallow deer introduced by people, which
kept such colouring for all further life. One more attribute of buck maturity
is a mane hanging down as tousle from its neck. But all the same this animal
looks not so majestic, as in autumn. The main ornament of ultradama is huge
horns with shovel-like expansions on the ends. Old horns had fallen off in the
beginning of winter, upon the termination of courtship season, and new ones
only have begun to grow – now these are simply small outgrowths covered by velvety
skin. To an autumn horns will grow up to the full size, and this animal will
become the true king of a local nature. But now it uses advantages of the condition
– while horns are short enough, ultradama buck can come into rich wood and it
is much easier to it to move now. To the summer, when horns will grow to considerable
size, it will come to move in bushes and to put additional efforts to carry
such heavy ornament proudly.
Deer buck walks to lake shore using one of numerous tracks. Its hooves tap on
stones sticking out here and there from the ground, and this sound, transmitted
through the ground and stones, is perfectly heard by underwater inhabitants.
In lake there are no the animals capable to attack huge deer, but presence of
large and heavy animal frightens inhabitants of lake. Tiny fishes in school
have rushed away from the shore and have hided in floating thickets of aquatic
fern. It is quite natural to them to be on the lookout and to be afraid of everything
– in lake ones hunting them live also.
In shallow water thickets of water plants move, and from lake bottom clubs of
silt and partially rotten fallen foliage have risen. From its ambush huge amphibian
– neohanasaki – has crept
out. This creature is similar to a huge salamander – length of its body is about
one and a half meters. And because of it the more surprising is that as a matter
of fact neohanasaki is a huge tadpole which will never become an adult one.
One group of frogs descending from human-introduced Australian tree frog Litoria
has simply evolved in a direction of occurrence of neotenic tadpole, only in
part turning into adult individual. The appearing of four-legged caudate creatures
capable to breed, not turning to a frog, became a result of this direction of
evolution. And neohanasaki represents some kind of apotheosis of development
of “adult tadpoles” group.
This predatory amphibian hunted, having dug in dust on lake bottom and waiting
while any tiny creature will swim up close enough to its muzzle to be literally
soaked up in a mouth, when predator sharply opens its jaws. But the appearing
of huge deer has scared away all fishes from the coast, and now the monster
has simply nothing to wait here. When deer has lowered its head to water and
began drinking, neohanasaki has begun to move tail lazily and has swum away
from the shore coast, from time to time pushing from the bottom by weak paws.
This predator eats mainly fish, and in lake it still will find many tasty animals
for itself.
Lake shores are overgrown with marsh plants giving a shelter to various kinds
of birds. It is too early now for hatching the posterity, but birds prepare
to forthcoming nesting season, occupying suitable territories and looking for
breeding partners for them. After sunrise their muster becomes louder, and from
thickets some more new inhabitants of lake appear – mainly ducks of various
species. In thickets voices of rails and swamp hens behaving very secretively
are heard. The lake has entered the time of its maturity: its shores are covered
with diverse marsh and aquatic vegetation, but the features of bogging are not
shown yet. This lake has some more thousand years of life ahead before it will
turn to the circuit of marshes and finally will be overgrown with forest.
On surface of water, like green foam, small Azolla fern floats, almost unchanged
from Holocene epoch. In fact, the presence of this plant in New Zealand flora
is one of set of traces of human existence on the Earth. Some ducks include
this plant in their diet, constraining its fast growth in the certain degree.
In coastal zone, where water is warmed better, Azolla floats like large velvety
islets surrounded by duckweed. Sometimes the surface of carpet of this tiny
fern waves; it indicates an abundance of underwater life. Many fishes of various
species live in lake, and their dark backs flash among floating plants in places
where open water stays.
Floating plants represent a fine shelter for fishes: so they are more difficult
for noticing from air. Besides on floating islets of Azolla various insects
often alight to have a rest; the part of their life cycle passes in water of
this lake. And in thickness of fern thickets mosquito larvae hide willingly.
Small caddis flies, mosquitoes and midges hover above water, living their fussy
short-term lives. And some of their neighbours aspire to make their life even
shorter in every possible way.
When the sun rises above and begins to heat hotter, above the surface of lake
dragonflies of various species appear. Dragonflies may be sizable frequently,
and sparkle in air like brightly colored arrows with metal shine, and some of
them in addition display black spots on wings. Their colouring is bright, but
these dragonflies are not afraid to be eaten by any bird – their flight is so
prompt, that only rare bird will manage to catch them. Damselflies are not so
fast; they frequently simply hang in air above the chosen site of water, making
short rush to chase any small insect flying nearby. At these predatory insects
not only the body, but also wings can have bright colouring, that makes them
some of the most beautiful inhabitants of lake.
The demoiselle damselfly, which body is colored blue with metal shine, hovered
for a while above water, trembling its transparent blue wings and goggling with
convex eyes. It looks for midges, hovering in swarms above Azolla thickets,
but it hardly understands, that it became object of supervision itself. Convex
eyes watch it from under water, and fins move slightly, moving slowly a streamline
predator’s body forward, closer to its prey. Through a small hole in Azolla
carpet demoiselle is perfectly visible from under water and it is enough to
make one exact rush only.
The carpet of floating fern as if had blown up: in fountain of splashes from
water the fish has jumped out, being little bit similar to small pike, with
large eyes and lengthened peaked jaws. Jaws have swung open, extended forward
as a wide tube and have sharply slammed immediately, but ineffectually: insect
managed to fly off at last instant. Fish plopped down in water, and green carpet
of floating fern closed above it.
Moving its transparent fins, fish has slowly swum under fern carpet, trying
to swim as fast as possible across the sites where through thickets beams of
sunlight penetrate in water. Maybe, the sunlight involves other creatures, but
this fish at an opportunity of choice prefers to remain in shadow and to expose
itself to eyes of the possible prey less often. The fish is named ‘ika-kaihopu,
and it is a local species of viviparous fishes, a product of last 25 million
years of evolution of the species appeared at the islands according the human
will: it is a descendant of the introduced species, of mosquitofish. In human
epoch the uniqueness of nature of New Zealand was substantially broken by people,
and in Neocene numerous species of fishes inhabiting fresh waters of archipelago
are descendants of the human-introduced forms. Evolution has transformed this
descendant of tiny and ordinary-looking fish to dexterous and specialized predator.
Large convex eyes of ‘ika-kaihopu help it tracking down wriggling mosquito larva
in plant thickets, and in this case its lengthened snout with pointed jaw tips
works as tweezers. The body of ‘ika-kaihopu is a body of sprinter, capable to
make a lightning jump to chase prey. Larvae of mosquitoes and other insects,
and also fry of various fishes, settling among floating plants, make only small
part of a diet of this kind. The most delicious prey for ‘ika-kaihopu includes
flying insects. The dragonfly spending the night carelessly on stalk of plant
low above water, or sluggish butterfly brought to the lake by wind represents
the desired prey for ‘ika-kaihopu. One jump – and fish overtakes its winged
victim. Widely opened mouth of fish turns to a tube at this moment. Body colouring
of ‘ika-kaihopu helps this fish to mask among plants – the spotty back is indiscernible
on the background of carpet of floating Azolla fern, and greenish colouring
of sides helps fish to remain imperceptible for eyes of underwater predators.
‘Ika-kaihopu is only one of many species of fishes inhabiting this lake. And
abundance of fish is a basis for successful existence of other inhabitants of
fresh waters of New Zealand.
Under water the body of streamline outlines flashes. This is a creature of small
size, but it is difficult to descry it against the background of bottom because
of dark back. In beams of sun silvery sides of tiny fishes trying to escape
it sparkle. Pursuing them, the creature makes sharp turns at the great speed,
and then for few moments its snow-white stomach is appreciable. Speed of its
movement is great, and its lunges frequently finish successfully: in thickness
of water here and there silvery scales turn, falling on bottom – it is the only
thing remained from fishes seized by this one. From time to time the creature
rises to the lake surface and jumps from water, looking thus like a tiny dolphin,
but then dives again.
But soon hunting is finished, and the creature swims to the shore. At the shoaliness
covered by the sun its body with peaked mobile head and fins flapping like wings
become distinct. Or are they really the true wings? The creature comes up to
shallow water, straightens its body and moves to the shore, ridiculously rolling
over on short legs. Now the picture is full: it is a very small penguin. Following
it from lake some more birds appear. They leave water and hobble along the narrow
track to the forest. Some tracks leading from forest to water are made by them
and are used by some generations of these birds in succession.
Birds walk on the track to the forest and move now into the fern thickets. For
people it would be strange to see these birds in forest, because in memory of
people penguins were always associated with the sea. But here these birds obviously
feel like very much confidently. They move so dexterously, that only casual
moving of fern fronds and hardly heard rustle of leaves under their paws give
out their presence. Besides colouring of backs of these birds is grayish-brown,
and even spotty at some individuals. It makes birds poorly distinct among thickets,
especially for those ones, which like to search for prey from above, from tree
crones.
Penguins have gone already approximately one hundred meters deep into the forest,
and one of birds has uttered short call. Reciprocal call is heard immediately,
and then one more follows. Other birds also began calling, and new voices began
answering them. It turns out, many penguins live in forest; they simply became
somewhat similar to other forest inhabitants, having learned to be imperceptible
when it is necessary.
These birds are New Zealand mountain penguins. Resettlement of their ancestors
to these places has taken place in quite natural way – during the global “plankton
accident”, directly or indirectly destroyed a significant part of sea inhabitants.
Escaping themselves from food shortage caused by “plankton accident”, ancestors
of these birds have adapted to life in fresh water, and their survival, as it
is paradoxical, had been provided by human activity: the main fodder resource
for these birds represents the descendants of fishes introduced to the islands
by people. New Zealand mountain penguins settle near the rivers and lakes of
both islands and live in small colonies between which there is a certain contact
– from time to time by virtue of various reasons birds one by one or in breeding
pairs move to the next colonies.
New Zealand of Neocene epoch is a place where it is rather difficult to live
to flightless birds and ones nesting on the ground. Islands are inhabited by
numerous mammalian predators, descendants of the kinds introduced by people.
Some birds, living in this island world changed up to unrecognizability, also
have turned to dangerous predators capable to compete in forces with mammals
of comparable size. Therefore the skills of shelter building and becoming imperceptible
are very important, if somebody wants to survive in such environment. New Zealand
mountain penguins have succeeded in art of shelter construction. The colony
of birds in forest near the lake numbers approximately twenty pairs and several
birds temporarily remaining without partner. At the order of these birds there
are about thirty holes dug out among stones and under roots of trees. It is
made intentionally to prevent predators to dig out holes – stones and roots
complicate this work.
Penguins come back from the lake with stomachs full of tiny fish. One of them
even managed to catch rare prey – in its stomach the young individual of neohanasaki
curtailed as a ring lays. While these creatures are small, it is not necessary
to be afraid of them and even it is possible to eat them unpunishably. And the
adult individual of this “tadpole” can easily swallow the small penguin entirely
– it is enough only to open mouth in right moment. While penguins gorge on for
themselves – the time to brood chicks had not come yet, but already just about
to come. Before the nesting both birds of pair need to be fattened well. The
care of chicks is the self-denying occupation is taking away lots of energy.
Taking care to chicks, adult birds grow thin strongly and live half-starving.
Therefore, while there is an opportunity, they try to live for themselves.
When successful fishers return to the colony, from holes their nesting partners
appear. Pairs at New Zealand mountain penguins are kept all life long or until
one of birds will perish. Breeding partners care about each other gently: they
clean each other’s plumage on head and around of eyes, share prey and in common
defend the territory against neighbours – it is the ground approximately one
meter in radius from an entrance of the hole. Therefore the bird coming back
to the hole is compelled to enter the conflict with the several individuals
perceiving its occurrence as an encroachment to their possession.
One of penguins, having filled its stomach with fish to the full, walks clumsily
to the hole under roots of large tree. But this way is accompanied day-to-day
by small skirmishes with at least three pairs of neighbours, and one hole is
dug out almost on the way of this penguin. Having reached up to the edge of
colony, it has uttered the salutatory call addressed to its female, and it immediately
has got out of their hole and has answered to it. Rolling over and having spread
wings wide, penguin has bustled to the hole. Jumping over tree roots and falling,
it has crossed the territory of one of its congeners while that one has not
returned. It also prefers not to stay for long on the territory of amicable
breeding pair, because it may be nibbled fairly. And when it passed the territory
of the third pair of congeners, its tail appeared in dangerous affinity from
an entrance to other’s hole and the female waiting for its male patiently has
jumped out and has seized its scanty tail by beak. The penguin has screamed
and has pulled, has fallen down the ground, has jumped again and has run, trying
to reach its own hole as fast, as it can. Its female, seeing, that her spouse
has undergone to an attack, has cried and has begun to clap flipper-like wings,
hoping to impress an aggressor. Having reached her, male turned around and they
began to cry to neighbour’s female together. It has receded at once, seeing
that it appeared in minority, and the conflict has died away as quickly as it
has inflamed.
When no more occasions for scandal with neighbours remain, the pair of penguins
has exchanged overdue greetings, having touched beaks of each other. After that
female, having sat down in front of male, began to stick suppliantly with its
beak to male’s beak from below. This action is clear to any penguin busy with
chick rearing and means only the wish to be fed. Having pulled its neck for
some times, male penguin has opened its mouth, giving the partner an opportunity
to pull out prey from its gullet on its own.
Fishing is connected to danger sometimes – large fishes, able to swallow the
adult penguin entirely, are found in lake. But on land the number of dangers
is not less, therefore penguins should to be on the lookout constantly. Their
alarm signal sounds more silently, than a usual voice, but it is distinguished
well by the whole colony.
Among the New Zealand forest predators the special place is taken by feathery
murderer named ruacapangi.
This bird, as against to carnivorous mammals of archipelago, is the descendant
of a native kind, and, probably, the presence of small carnivorous mammals had
forced its ancestors to join the “arms race”, that had resulted in appearing
of this predator. Being a bird, ruacapangi has quite good competitiveness on
the background of local fauna of carnivorous mammals, and local herbivore beasts
frequently become its prey. It has keen hearing, fine sight, fast feet and strong
beak making fatal wounds to small animals.
Ruacapangi, large adult female, wanders in forest. When spring days will become
even warmer, it will meet the male and will begin nesting. But now it hunts
only for itself. Morning hunting appeared not too successful – ruacapangi tried
to prey any rodents, but no one attacks had been crowned with success, and it
had to peck up several beetles and one small frog to satisfy its famine for
any degree. Sense organs help this bird in search of prey, and it receives enough
information to understand who is around of it in forest. Somewhere in branches
above the head of bird rustle of feathers is heard – its constant satellite
of the last autumn and winter, eagle
kea keeps it up. This carnivorous parrot managed well, eating up the rests
of ruacapangi’s prey, but it was the true helper of this bird, more than once
guided it right to possible prey. The connection of these two birds is still
strong, and the parrot does not miss an opportunity to feast on the rests of
prey of its strong patron. In spring the vegetation becomes denser, and the
number of insects and other smaller animals grows. Therefore life of many medium-sized
inhabitants of New Zealandian forests becomes easier, and there is a great probability
that somebody of them will simply lose care, having been carried away with search
of food. And then the predator will not miss the chance.
It is very simply to find a colony of New Zealand mountain penguins: it is enough
to stand silently in forest and to listen. Being not frightened, these birds
call very loudly, establishing their relations, or simply communicating with
each other. Ruacapangi female already tried to hunt these birds. It does not
like taste of their fish-smelling meat, but it is an easy prey, if penguins
are taken unawares. And each individual ruacapangi perfects such skill during
all its life.
Ruacapangi has easily distinguished among forest noise voices of penguin colony.
Having slightly inclined its head to one side, the bird has listened, and then
directed to the colony by silent step. Eagle kea watching it from trees has
guessed upon the bird’s behaviour that it has found out possible prey, and has
simply stayed where it was, expecting in case of ruacapangi’s success to join
its meal later. But now its presence itself may be alarmed for possible bird’s
prey and break up the hunt.
Ruacapangi puts feet on the ground very cautiously, and the wood litter almost
does not rustle under its toes. The bird steals cautiously to the colony of
penguins, having bent down and having extended head and neck forward. After
each step it listens and freezes on the spot if voices in penguin colony suddenly
began to sound a little bit silently, than up to this moment. Ruacapangi moves
forward very cautiously, but it can not take into account all circumstances
which can prevent its hunting. And thin twig, having crackled foully under its
foot, discontinued all spent efforts instantly.
The crunch of twig is too sharply distinguished from the background of forest
noises, and an alarm signal in penguin colony became an answer to it. Voices
of penguins at once have ceased and ruacapangi has heard only footfall of small
legs on the ground, and then at the place, where some seconds ago birds cried
loudly, the silence fell. All insignificant conflicts appeared forgotten at
once, and strictly protected borders of territories as if disappeared. All birds
have instantly hided in holes and have broken off. While penguins do not nest,
some individuals have simply got into another’s holes, but in the face of the
common danger hole owners have not paid attention to it. Birds keep silence
and even have instinctively dropped to the ground to hide their presence. And
in silence they have heard sounds of steps – of long steps of very large creature.
And also the noise of wings of another creature is heard.
In penguin settlement ruacapangi walks and at the edge of colony of penguins
on the ground eagle kea stands and observes of its actions. Penguins behave
so silently, that from the side it seems, as if their colony has died out. While
it is difficult for bird to make a choice – both empty holes and holes in which
birds are hidden differ from each other in nothing in its opinion, while penguins
sit still. Therefore ruacapangi simply wanders randomly from one hole to another,
listening and scratching the ground by claws from time to time.
In one hole at the edge of the colony at once three penguins wait through dangerous
time – breeding pair which possesses the hole and male appeared in this hole
by the will of fate, because this one lives at the other side of the colony.
In usual life these birds met each other a little, but now they appeared in
immediate proximity from each other. And two males have not found anything better
than to begin to establish their relations. Newly arrived male has simply seized
by beak feathers of the male owned the hole in order to force it to move aside.
From unexpectedness attacked male had cackled shortly, and this sound was heard.
Ruacapangi has instantly defined, from what hole this short silent sound was
heard, and has reached it in two long jumps. But it was only the easiest part
of its task. Penguins are masters of construction of fortifications, and the
predatory bird has learned it to the full. The hole is dug out intentionally
near the big stone and is directed right under it. Ruacapangi has listened for
a while, and then has tried to dig out a hole, scratching the ground by claws.
But it had not succeeded to reach the success even a little bit: stones are
placed deep in the ground and are too heavy for this bird to shift them from
their place. Eagle kea, having seen than its patroness has become interested
in something, also has approached to the hole and has glanced into it, but has
run off aside when ruacapangi began digging out the ground again. The only thing
that it was possible to it to lay after approximately ten minutes of persistent
work was to turn out a small stone from the ground. Larger stones are too heavy
to be removed; therefore dwelling of penguins is almost not touched as a whole.
Ruacapangi is tired fairly while attacking an underground fortress of penguins,
and it would not like to continue unsuccessful attempts to reach the hidden
birds. Therefore it simply walks here and there on territory of the colony,
turning head to any noise and hoping to profit by any casual prey. Penguins
have stood in holes. Only due to alternation of light and shadow and due to
quiet sounds from the surface they can guess what takes place near the entrances
of their holes.
Eagle kea did not begin to recede so quickly. Its size allows it pushing head
into the hole, and it does not miss an opportunity to check up a hole of penguins
left by ruacapangi. Having stolen up to the hole cautiously, it has pushed head
inside and has clicked its beak in darkness. The hole appeared much deeper,
than parrot expected, and its beak has not reached any aim. The stranger penguin
has nestled against earthen floor of hole: the beak has not touched it, but
has clicked in dangerous affinity from its tail. Eagle kea has obviously decided
to stay here for long: it has pulled head out from hole, has darted a glance
at ruacapangi wandering at the opposite edge of the colony, and then clambered
into the hole again. And at this moment the penguin appeared in another’s hole
has decided to act: it turned around in hole, crept along the wall of hole and
has seized plumage on eagle kea’s head by beak, right near its eye. Crying loudly,
the predatory parrot has pulled its head out from a hole. Fair flock of plumage
appeared ripped out at it, and from the wounded skin blood leaked.
Ruacapangi has hardly paid attention to problems which its hunting partner has
faced. It lives for itself, and this parrot is only a part of world around,
not better and not worse than all the rest. Therefore ruacapangi simply is not
going to react to its problems.
The attention of ruacapangi was involved with rustle in ferns. The bird has
raised head and has looked round, trying to detect a source of noise. It noticed
how in fern thickets among trees some fronds shudder and move. And noise is
heard therefrom. Ruacapangi has made some fast steps aside a source of noise,
and began to peer into thickets. One penguin simply has not had time to hide
in hole and has hidden on the ground. Due to colouring of back it is invisible
among wood dust when stands motionless. It has noticed in proper time that ruacapangi
moves towards it, therefore has simply lain on the ground, hiding its white
belly, and freeze. The endurance of the penguin can be envied: ruacapangi, huge
in comparison with it, passes almost near to it, having almost touched the penguin
with its claw. Despite of it, the penguin keeps immovability up to last moment.
Having looked round, ruacapangi made some more some steps and has returned to
the colony. The penguin can not remain motionless for long: it is the great
probability of being found out and seized nevertheless. It also will be not
possible to hide in colony for the bird: the voice of eagle kea, which also
will not miss an opportunity to attack it, is heard there. Therefore the penguin
makes the desperate decision: it stands and rushes to water at full speed.
Ruacapangi has turned back in direction of rustle and has seen fern fronds shuddering:
someone small will get away from it, being hidden among plants. The intelligence
of this bird is not so high; therefore its response is predicted: ruacapangi
has rushed to chase it not trying to understand at all, what creature is pursued.
Prey is hardly visible under ferns, but it is obvious that it is someone small
for ruacapangi to cope with it easily. The penguin has advantage: it has low
growth, therefore ferns hide it, and from height of ruacapangi growth it is
poorly visible. The large predatory bird should stop to understand, where the
penguin pursued by it runs. Penguin easily changes the direction of run, forcing
long-legged bird to reduce speed of run on turns. Besides the penguin perfectly
sees road on which it is running, and ruacapangi does not notice roots of trees,
coiling on the ground. And during one lunge ruacapangi has simply stumbled over
the root and had broken claw tip. Not wasting time, penguin crossed the zone
of thin forest, where ferns do not grow any more, and has directed to lake shore.
It is tired strongly and runs with what is left of its forces. Rates are not
equal in this struggle of predator and prey: the predator loses only some food,
but prey in case of loss will lose its own life. Therefore the penguin has directed
right to the water. Behind its back footfall is heard: ruacapangi runs closer
and closer to it. Some seconds will decide everything, and the penguin is going
to win the time. It has rushed to water and has dived. Having jumped out to
the lake shore, ruacapangi has seen only thin chain of air bubbles marking its
way under water. Having come up, the penguin has looked round and has seen ruacapangi
running along the shore forth and back, obviously trying to guess where the
pursued penguin will appear. Having seen it, the predatory bird has bravely
come in water and has made some steps on the bottom. But here it is not in its
element, but the penguin feels like very much confidently. Having seen that
ruacapangi comes nearer, the penguin has simply dived and in some seconds was
put out from water already in deeper place, farther from the shore. Ruacapangi
has made some more steps, and water has already wetted feathers on its stomach.
Having pecked the thickets of Azolla fern floating on water surface, ruacapangi
turned around and dragged itself to the land. Having got out on land, bird has
shaked feathers and has walked back into the forest. And among branches the
silhouette of large bird has appeared – eagle kea has decided not to lag behind
the predator yet, even if now it was unlucky.
The penguin has cautiously swum up to the shore, has emerged among floating
plants and began to look around, trying to estimate the degree of the danger.
Having convinced that ruacapangi went off, it has got out to the shore, sinking
in stalks of coastal plants, and has rushed to the colony at full speed. Now
it just got lucky, but nobody can know, as far as successfully there will be
even a next day of its life.
Penguin is lucky now, but it also happens, that predator is onto a good thing.
Nevertheless, penguin colonies near the rivers and lakes of New Zealand exist
stably enough, and sometimes even prosper. This is promoted in great degree
by abundance of fish in fresh waters of islands, which became possible also
due to human activity in historical epoch. Various kinds of fishes, descended
mostly from the species introduced by people, are found in lake. Among fishes
of New Zealand there are also descendants of native fishes and the species settled
in the rivers and lakes of islands already after the end of human epoch. But
the number of such species of fishes is insignificant.
New Zealand mountain penguins have good appetite, despite of their size, and
go to fishing one or two times per day, depending on their luck in previous
case and the degree of hunger of the other bird of their pair. They obviously
prefer to hunt in group of congeners – this way it is easier to chase small
fish, which they eat, and to cut off the ways to escape.
The group of five small penguins has left colony and has gone to lake. Walking
in forest, these birds prefer to keep secretively, trying to hide from eyes
of possible predators. They choose a way among fern thickets, hiding under lacy
plant fronds. Plants feel the beginning of spring, and in the middles of last
year’s rosettes of ferns clusters of young fronds, turned to sappy hard green
spirals have already appeared. But every day the sun will heat stronger and
shine longer a little bit, and thickets of ferns will be decorated with fresh
greens, providing penguins with good shelter from extraneous eyes. At the forest
edge thickets of ferns thin appreciably, therefore penguins should behave more
cautiously. They run in group from one tree to another, looking round for a
long before making the following dash. And at the lake shore they run, not stopping,
and at once dive into water.
Under water penguins swim and flap wings, as if in flight. They gather speed
quickly, swim under thickets of floating plants and jump out of water already
far from the shore, like tiny dolphins, and their wet backs shine in sunlight.
Having caught their breath and having made a deep inhalation, penguins almost
simultaneously dive and begin their hunt. They prefer to swim at the depth of
about two meters that is rather deep for such tiny creatures, but allows coming
nearer to prey, being almost unnoticed – brownish backs of birds are almost
invisible on the background of lake bottom.
Penguins perfectly distinguish their prey – school of small fishes feeding on
tiny planktonic crustaceans at the surface of water. These fishes are New Zealand
eversmolts, descendants of the human-introduced trout. As a matter of fact,
this species is dwarfish trout migrating for spawning to mountain streams. It
has kept the adherence to clean water rich in oxygen, characteristic for its
ancestors, and prefers to keep in mouths of the rivers flowing into lake. Here
water is cooler and also richer in oxygen. Here spring changes in nature are
felt especially clearly: when snow thaws in mountains, eversmolts feel changes
in chemical compound of water, and it serves as a signal for them for the beginning
of preparation to spawning.
The mouth of the river has become overgrown with rich thickets of pondweed.
Due to creeping rhizomes and long roots this plant firmly keeps for the bottom
and can maintain a current of river running into lake. Long stalks of pondweed,
covered with numerous leaves with a pinkish underside, wave in current, serving
as fine shelter for New Zealand eversmolts. Colouring of this small fish helps
it to remain imperceptible in the world full of predators. Out of courtship
season males and females of New Zealand eversmolt are colored in similar way:
they are silvery with black marble pattern on sides. If such fish hides in plant
thickets, it cannot be noticed.
The school of eversmolts keeps near to pondweed thickets. From time to time
fishes dart into thicket of plants in searches of insect larvae and others small
invertebrates, but then come back in open water. Some fishes swim near water
surface, and among leaves floating on surface their spotty backs flash. When
certain tiny moth has flown by above the surface of water, from thickets some
eversmolts have jumped out one by one, following it, but no one of them manage
to catch it. In the beginning of spring the number of flying insects is low,
therefore those few individuals that fly above water serve as an object of steadfast
attention of underwater hunters. But eversmolts obviously do not suspect that
hunters for them are already close.
The group of New Zealand mountain penguins has simultaneously emerged to inhale,
has synchronously dived and has swam to pondweed thickets along the lake shore,
hiding in shadow of floating plants. They already have well fulfilled strategy
for hunting of cautious eversmolt. The fish is quick; therefore, if it would
disappear in thickets, it would be impossible to be caught. Penguins have inhaled
air once again, have dived and have rushed to thickets. Birds do not try to
attack fishes, even if they see how the lengthened bodies of eversmolts flash
near them and their scales shine. Penguins simply drive fishes from their shelters,
not giving them any opportunity to return there. The round-up of penguins has
gone right: from thickets some young ‘ika-kaihopu fishes darted, and they were
followed by the whole school of eversmolts. All fishes are frightened and instinctively
gather to the common school. Even ‘ika-kaihopus nestle close to eversmolts,
trying to hide in their flight. In few seconds from thickets their pursuers
have appeared and hunting has proceeded. Penguins drive fishes away from saving
thickets, cutting off the way to escape. From time to time any birds rises to
water surface, inhales fresh air and rushes to the center of fish school. If
the rush finishes successfully, bird swallows prey right on the move and continues
hunting, but now as drover and its place is occupied by another individual.
One ‘ika-kaihopu fish has tried to avoid the fate prepared for it. It has escaped
from the congestion of eversmolts surrounded it, and has jumped out of water,
having disappeared from the field of view of penguins. Maneuver has gone right:
it has plopped in water far behind the pursuers and has rushed immediately to
thickets, moving by zigzags. In beams of sunlight the scales on its sides flashes,
and these short-term flashes only confuse possible chasers. But penguins do
not pay attention to one fish managed to escape: the main prey is here. Penguins
continue hunting, preventing the spread of eversmolt school. They eat small
fishes one by one, not giving them any opportunity to escape.
Saving thickets have remained far behind, and the bottom is far in depth now.
Eversmolt school keeps right under the surface of water, and each fish tries
to hide behind the bodies of congeners. Some fishes jump from water, but it
does not help them – they inevitably return to the water, where they are attacked
by penguins.
The birds keen on hunting have not noticed, that splashing of eversmolt school
has drawn attention of one more lake inhabitant. In thickness of water the silhouette
of large fish – monster of about one meter long – appears gradually. This lake
inhabitant has large head, and body rises behind its nape like high hump. This
fish tries to not give out its presence: having noticed eversmolts and penguins
hunting them, it has only dived deeper and began coming closer cautiously to
the place of a drama. One penguin, having caught and having swallowed one eversmolt,
has dived to help its relatives to keep school of eversmolts captive. But during
the dive it has noticed absolutely casually, how weak sunlight has flashed in
the eye of large fish. The penguin has rushed to the surface, breaking the hunting
formation of congeners, has made a long jump above water, having inhaled air,
and has rushed away. Its panic has disturbed other birds; they began looking
around, and one bird has noticed under itself cross-striped back of huge fish.
Not waiting while the fish will start an attack, penguins have rushed away.
Keen on hunting, they have swum too far from lake shore, and now their lives
are threatened with real danger.
The monster has waved its tail and has rushed from depths to water surface,
right in the middle of eversmolt school. The wide mouth with pointed teeth has
swept open, and one eversmolt has disappeared, being sucked into the mouth of
fish with a stream of water. Eversmolts have rushed every which way, and at
the place where their school rushed some moments ago, under the water surface
the large striped fish swims. It is the largest species of fishes in this lake
– ‘ika-taikaha. Vertical stripes on body, spiny fins, humped back and predatory
habit of life are the features inherited by this giant from its ancestor – European
perch introduced to New Zealand from Europe in historical epoch. The creature
formed in conditions of struggle for existence in rivers of its native land
has got accustomed well in new place, and in the subsequent millions years has
undergone very few changes. Actually, ‘ika-taikaha is simply a perch of huge
size. It has “twin brother” in far Venedian
Lake at the north of Europe: both species independently from each other
have got out on top of food pyramid in their habitats.
‘Ika-taikaha is a gluttonous predator not disdaining any prey – it is enough
for it only to squeeze into its gullet. And small eversmolt does not satisfy
famine, and only works up an appetite. The penguins scared by appearing of this
monster, try to move off its way as quickly, as they can. Desperately flapping
their wings, they are swimming away, keeping near the surface of water. By their
size these birds are just suitable for a role of dinner for ‘ika-taikaha, and
it seems, fish is going to catch for dinner something larger than small fish.
Moving tail and having lowered its back fin, ‘ika-taikaha rushes to chase penguins
seeking safety in flight. It has chosen one of birds lagged behind others for
its attack, and now its attention is concentrated on this prey.
To escape, penguins need to reach the shore – while depth is enough for swimming
for ‘ika-taikaha, they can not feel like in safety. It seems, the pursued penguin
has guessed, what may be its fate, and tries to escape desperately. It jumps
from water like a dolphin, inhaling air and simultaneously gathering speed of
the movement. This tactics brings the result: the huge fish lags behind, as
it is not adapted to a long pursuit. And saving thickets of pondweed in mouth
of the river, flowing to the lake from mountains, are closer and closer. Desperately
flapping its wings, the penguin, as if a bullet, ran into thickets of underwater
plants and has disappeared from the view. Making the way through thickets to
the land, penguin has not noticed a striped fish side next to itself. It has
hastened to the shore, but its movements have frightened away one more fish
– young ‘ika-taikaha, longer a little bit than the penguin.
As against the adult individuals patrolling open water at some distance from
the shore, young ‘ika-taikaha fishes prefer to live in shelters. To hide better,
young individual of this species has more contrast cross strips and expressed
greenish background colouring of body. Scared by sudden occurrence of the penguin,
young ‘ika-taikaha has rushed away from thickets, and faced nearly face to face
the adult relative pursuing that bird. The mouth of the giant has opened almost
automatically, and the next second pointed teeth stuck into flesh of young fish.
The tail of prey pulled some time in spasms, and then the adult ‘ika-taikaha
has opened its mouth a little bit wider and has accurately pushed prey into
the gullet. The feeling of satiety has brought peace to the huge fish. Moving
its fins lazily, the adult ‘ika-taikaha turned around and has swam away into
the depth. Fish even has not paid attention to young neohanasaki rushed away
from the bottom in cloud of silt at its approach. The fish returns to its territory
in order to have a rest on the bottom in favourite hole and to devote some days
to digestion of its prey. It is too cold now to search for the breeding partner,
and it is still possible to lead the same slow and measured life, as in winter.
Spring inevitably wins from winter the positions in nature, and the change of
the seasons is more and more appreciable every new day. Spring days become longer,
the sun rises higher and heats hotter. Snow at mountain tops thaws and the rivers
running into lake turn to rough streams. Chemical characteristics of water change
– it becomes fresher, more transparent and richer in oxygen. Plants react to
increase of light exposure by intense growth; therefore stones in mountain streams
exposed to bright sunlight are overgrown by greenish film of microalgae. And
the abundance of food stimulates breeding of small animals, which turn prey
to larger inhabitants of mountain streams and rivers. Larvae of mayflies, midges
and mosquitoes scrape algal film and eat microscopic worms and protozoans settling
among microalgae cells.
Largest ones among permanent residents of mountain rivers after the beginning
of spring also became more active and they may be frequently noticed on stones
overgrown with algae. Large creatures of brown color with black longitudinal
strips stretched along each side of this animal attach to stones among whirlpools.
Their lengthened bodies wriggle in current, and the sucker mouth on the bottom
side of flattened head allows keeping firmly on smooth surface of stone and
to resist to current. They resemble fishes very much, but at close look one
strange feature of their shape is found out: they do not have paired fins –
pectoral and abdominal – and in fin plica bordering body and tail fin rays characteristic
for fishes are not present. These creatures are not fishes at all, but tadpoles
of local rangitahi frog. It is one more masterpiece of evolution of tailless
amphibians in the rivers of archipelago. Rangitahi frogs spend some years in
condition of a tadpole. It allows them to use the food resource inaccessible
to adult individuals – microscopic aquatic animals and unicellular algae. The
low temperature of water in rangitahi tadpoles’ habitat slows down the metabolism
and allows them to be content with a small amount of food; therefore in every
mountain stream rangitahi tadpoles are rather numerous. Among them there are
individuals of various ages – from tiny creatures hatched in previous spring
up to large individuals about 25 cm long. These are the five years old creatures
ready to transformation to adult frogs in the nearest future.
Tadpoles are among the largest inhabitants of mountain streams. They cling to
stones by oral sucker and leave behind only clear paths in algal films. Each
tadpole protects the territory zealously, not permitting relatives to swim to
it. If it is necessary, it will drive strangers away from the territory by impacts
of sides and tail.
The most plentiful algal epibioses are formed on the top side of stones, which
is only slightly covered with water. In addition the current is not such strong
here, and the spring sun warms well. Therefore, when water in streams rises
and covers the stones, which usually stick out from water, tadpoles move to
such places for feeding. But it is the great risk, and they should be cautious:
nearby there can be predators, and the meeting with them does not promise anything
good to any creature not able to be protect itself actively.
Large tadpole about four years old crawls on the surface of stone. Here algae
form moss-like layer which it eats with pleasure. If the skin dries up in wind,
the tadpole reaches a deepening on the surface of stone with sharp movements
of tail and pours sparks over itself, and then continues scraping algae. Its
small unblinking eyes look indifferently upwards and in sides. Its way of life
is primitive and simple, and it does not need to express the feelings and emotions
for survival. It simply eats, simultaneously keeping up the occurrence of possible
danger.
It is no need to wait for it for a long: danger has found it itself. When the
shadow swooped above the surface of stone, and the sight of tadpole has distinguished
quickly moving black spot on light background of sky, reaction of animal was
predicted and automatic: having waved tail here and there, the tadpole has scrambled
along the stone, has fallen down in water and has immediately stuck to lateral
face of stone in a shadow.
The black wings flashed in the sky belong to New Zealand false raven, one of
widespread birds of New Zealand. Like many species living at these islands in
Neocene epoch, this bird is the descendant of the introduced species, of rook.
And in shape of bird its relationship is guessed: the adult bird has white beak
clearly visible on background of black plumage. It is the large adult male,
its wingspan reaches 160 cm. Near to it the female keeps, not making a concession
to it in size – it is a breeding pair united for nesting some years ago and
not leaving each other since that time. Success in a survival of New Zealand
false ravens is provided by family features of corvids – by high intelligence
and ability to learning and storing of the information. Both these birds keep
in minds great life experience and skillfully apply it in search of food and
protection against enemies. They know many receptions of hunting for various
small animals living in New Zealand, and remain hungry for night seldom. And
these birds had been involved to the stream with an opportunity to catch small
invertebrates and even fish in case of luck. Rangitahi tadpoles also represent
quite good prey; both birds of this pair are able to catch them and taste of
soft meat of these creatures is well familiar to them.
Female perched on stone sticking from water and began peering steadfastly into
the stream. Among the puzzle- work of gleam and shadow at the bottom and flashes
of sunlight on water surface it managed to distinguish body of one tadpole extended
motionlessly. It has attached by sucker to the stone and keeps an immovability,
hoping thus to wait danger. But the hunter nevertheless is more artful, than
its prey: having convinced by that prey is recognized correctly, female of New
Zealand false raven by single fast movement has dipped head into the water,
has seized tadpole’s tail by one exact movement, has pulled out it from water
and has strongly struck against the stone. When prey has stopped pulling, the
bird has pressed it by paw against the surface of stone and began pecking it.
Other rangitahi tadpoles were hid quickly. Some of them have simply rushed to
middle of stream channel, where it is deeper and it is more difficult to get
them. Some more tadpoles have swum away under the edge of stone and have stuck
to it from below, having squeezed into narrow cracks. Male of New Zealand false
raven was late a little and it would hardly catch prey as easily as female has
made it. Of course, it has tried to take away prey at female, but she stopped
his attempt by loud cries and menacing display. After that she has seized the
rest of prey and has swallowed it entirely, knowing, that her partner in life,
probably, would try to force her to share prey once again. When after the caught
tadpole only some spots of blood on stone remained, male had an opportunity
only to flutter to the next stone and once again to try to catch dinner for
it independently. It has seen how one tadpole darted away under the stone on
which it stands. Male raven walked to the edge of stone and took a look in water
by one eye. It managed to discern the tip of tail of rangitahi tadpole which
has begun to move and has passed out of sight immediately. Male raven decided
to try to seize this tadpole. It has quickly put its head under water, has run
slightly opened beak over the bottom edge of stone and at once has pulled out
its head from water. The first attempt has not gone right, but it obviously
has not stopped the raven. It has an experience in getting various small animals
from their shelters – it is possible simply to stick into such shelter something
long and thin to force prey to leave its shelter. It has flied up and was landed
on the ground. Strolling in growing grass, the raven has seen some dry last
year’s stalks of the grasses, just of the necessary length, straight and strong
enough. Having seized one stalk by beak, the raven has loosened it and has pulled
out from the ground. Its female has expressed clear interest in manipulations
it makes. The raven has returned on stone under which rangitahi tadpoles are
hidden, has put the found stalk on stone, and then has taken its tip by the
beak, has put its opposite end under stone and began to move it there. Female
has fluttered on the male’s stone, has approached to it and began peering into
the water steadfastly. The scared tadpoles, escaping from the enemy never seen
before, have rushed out from under stone. Male has not had time to let out a
stalk used to frighten prey, and female has already seized rangitahi tadpole
and has stunned it by impact against stone. But this time, however, it was not
possible for her to take advantage of fruits of her own success: male let off
a stalk, has pushed her away inconsiderately and began pecking prey itself.
The pair of ravens is too keen on hunting for tadpoles, therefore birds have
not noticed, that they became an object of steadfast attention of one more predator.
And not birds, but their hunting successes interest it so much. Having seen,
that birds have begun eating something, the predator has left its shelter and
was directed to them. It is not large in size, but thickset and has strong constitution.
Moreover, only one animal can have such characteristic black “mask” on white
muzzle – it is New Zealand
unbadger. This furious predator is the descendant of ferret introduced by
people in historical epoch. Because of such animals and their relatives at the
islands of New Zealand there are no flightless birds in Neocene, with the exception
of ruacapangi, and New Zealand mountain penguins had to transform their holes
into fortresses.
New Zealand unbadger does not try to hide from ravens’ view at all. It began
skipping from stone to stone, coming closer to birds and their prey with each
skip. Thus it behaves deliberately defiantly: opens mouth and shows its teeth,
lifts up tail to back, making the tuft of white hair growing on it especially
appreciable, and growls loudly. Seeing its approach, the couple of ravens has
displayed protective pose: they have slightly stretched wings, have slightly
bent down heads and have fluffed up feathers. On background of black plumage
their white beaks look especially impressively. Threat is supplemented with
loud croak of both birds. Unbadger has stopped on the next stone, at the distance
of one jump from birds and their prey. Ravens have obvious tactical advantage:
they can fly up and simply push this predator in water, having forced it to
take a cold bath. But unbadger wins in using of brute force, because it weighs
much more, than both birds taken together. Its chances to make use of prey of
ravens are rather great, and it is not going to recede. Seeing it, birds have
flied up and began to attack it in common, trying to peck the contender in head
or back. The beast should defend itself, opening mouth wide and growling threateningly.
It has managed to snap tip of wing of one raven, but the bird was escaped, having
left just two feathers in its teeth. Having received strong impact of beak in
back, unbadger has risen on hind legs, balancing on stone, and has prepared
for fight its clawed forepaws. But ravens also know some tactical tricks, and
silly beast is easy to deceive. Male raven began simply to fly above the muzzle
of predator, observing, however, a safe distance and distracting the unbadger’s
attention to it. And female has flown behind the beast at this time and at the
most improper moment has rushed on unbadger with the whole weight of its body,
having simultaneously put strong impact of beak in predator’s hindhead. Having
lost balance, unbadger plopped in cold spring water and fast current has carried
it away. Beast is wounded: on its head skin is slashed by impact of bird’s beak,
and from the wound blood exudes. Another’s prey appeared too expensive for it:
beast managed to get out on the ground only in several tens meters downstream.
It had shaked the wool, had smelt air and moved into bushes, stepping clumsily.
When predator had been carried away by the river, ravens have lost any interest
to it. Male has returned to the interrupted meal, having given the female the
right to catch prey independently while it is sated.
With the coming of spring in the colony of New Zealand mountain penguins preparations
for nesting begin. These birds, like New Zealand false raven, are monodins,
though their behaviour, certainly, is much simpler, than at ravens. The finally
formed pairs of birds keep amicably, trying not to separate. These are the partners
which have finally made the choice for the benefit of each other. At such birds,
got used to each other and showing some kind of “psychological compatibility”,
nesting and rearing of posterity passes much more successfully, than at the
birds formed breeding pair for the first time and not too suitable to each other
in temperament. But sometimes external circumstances interfere with family life
of penguins and then the settled pair ceases to exist. Such small birds have
too many enemies, and sometimes some penguins do not return to native colony.
Adult penguin female wanders alone in colony, looking around and from time to
time uttering loud advertisement call. During two previous years it has a breeding
partner; birds enjoyed life together, shared food, built and repair hole, took
care on posterity and defended chicks against enemies. Now life has turned another
side to this bird: female is a widow, though, probably, it does not realize
it yet. Yesterday her male had not returned from fishing: chasing for fish,
it has swum away too far from the shore and large ‘ika-taikaha has successfully
taken advantage of the hunting opportunity occurred. Female does not know it
and does not lose hope yet to meet him – wandering in colony, she looks in another’s
holes, calls and listens attentively to voices of neighbours, aspiring to hear
the answer to the appeal. But, unfortunately, in chorus of voices of her congeners
there is no that voice she wants to hear.
Within several next days this female calls her male less often, and is gradually
restrained with the status of the single bird. In her present status of widowed
female there is one more important circumstance determining her relations with
other birds of the colony. This female is “a wealthy widow”: she still owns
a good hole close to the protected center of the colony. While she made a pair
with her male, both birds could confirm the rights to the hole, giving the coordinated
repulse to neighbours. But now she is alone, and neighbours understand it not
worse than she does. When widowed female leaves for fishing, neighbours already
gradually begun inspect her hole. In their idea if nobody protects an entrance
to the hole, this hole is free to settle there. Two pairs of neighbours come
freely to the territory of lonely female and look into her hole. They do it
cautiously, as if expecting, that the second bird will jump out suddenly from
the hole and will rush on them. But nothing happens, and neighbours gradually
turn brave. However, one pair has quickly left from the number of applicants
for new dwelling: the second pair of penguins appeared both more amicable and
stronger. When lonely female comes back, they still move aside, but do not miss
an opportunity of breaking borders of territory around of her hole in a pointed
manner. The closer the nesting season, the more critical is “a housing problem”,
and more actively neighbours of widowed bird try to solve it. Next day male
from neighbour's pair simply got to her hole and began pinch the hole owning
female by beak. She has managed to defend against him and to expel the impudent
aggressor from her hole, but soon she had to leave a hole just to catch some
fish for herself.
Having returned about midday, female has found out that on her territory neighbour
male perambulates, meeting her with aggressive scream and obviously not going
to return to his territory. But one more occasion for anxiety became the head
of neighbor female appeared from her hole after male’s call; nobody knows how
much time she managed there. When lonely female has tried to get into her hole,
being her property even in the morning, she has met furious repulse from the
side of impudent usurper. Having find shelter in hole, her former neighbor female
began crying and pecking her, not letting the former owner of hole to come inside.
But, maybe, the hole usurper understands, that while her rights in property
are too illusive, and at approximately equal forces she shows features of uncertainty:
her voice sounds more silently, and she tries to avoid fight and recedes deep
into the hole. But male comes to help her: he gets involved in conflict and
begins pecking lonely female, and then simply pulls her by the tail from hole
entrance. Encouraged by such support, his female also has gone over to the offensive.
Together they have easily driven away lonely female from her hole. The taking
of her habitation is completed and now her troubles were increased in addition
– she does not have a shelter anymore, therefore, if now any predator like ruacapangi
or unbadger would attack the colony, she is doomed. Certainly, she can hide
in another’s hole for any time, but she would be expelled at once, when danger
would pass. In her present situation not only success in nesting in this season,
but also her own life appears under threat.
And life of other creatures proceeds. Snow in mountains of archipelago thaws
actively, and the river running into lake, has overflown banks, and the chemical
compound of it is changed a little in comparison with the condition in winter.
Changes in chemical composition of water determine life of aquatic animals in
many respects – using them underwater inhabitants feel change of seasons in
the greater degree, than using the temperature of water. The flow of fresh and
rich in oxygen water is the powerful initiator of courtship behaviour of eversmolts.
Cautious fishes begin preparing for arduous travel, which culmination will be
spawning in mountain streams. Maybe, for some of them this travel will be the
last one in their life – many difficulties wait for these small travelers at
their way to spawning areas. Like their ancestors, eversmolts remember a smell
of native stream and will aspire to spawn eggs in the same place where they
hatched.
Before the forthcoming travel eversmolt males have already started to change,
as if trying on the courtship dress. Their shape varies not as considerably,
as at salmons of human epoch: at them hump does not grow and jaws do not bend,
but the colouring changes only. Within several days males differ from females
appreciably: background colouring darkens at them, and on this background pinkish
spots appear. But these are only weak signs on the further magnificence which
will be shown to the full only at the spawning area.
Eversmolts gradually cease to hide and gather to schools in mouth of the river.
They prepare for spawning and at this time do not pay attention even to predators.
New Zealand mountain penguins use short-term availability of the favourite prey
to the full. They pierce through schools of eversmolts as if bullets, but fishes
do not rush to the shelters even if the congeners next to them appear in beaks
of birds. The loss is compensated by arrival of new schools from other parts
of lake during several next days. Schools of fishes unite gradually, and penguins
already are rather afraid to come nearer to this huge live mass: they cautiously
swim near to many thousands congestion of fishes, seizing only the individuals
strayed from a main bulk of relatives.
At last, according the invisible signal understandable only to fishes themselves,
eversmolts at once leave a river mouth and move to spawning areas. The school
of eversmolts enters the river, as if a rain cloud. New Zealand false ravens,
herons and other feathery lovers of fresh fish hover above the river and have
an opportunity to observe with their own eyes this magnificent show. Birds do
not miss an opportunity to fish: they land on stones along the riverbanks and
at the shallows, and almost at random peck fish swimming in dense school. Eversmolts
rush away and try to swim to the depth, but the density of school is those,
that one fish is immediately replaced by another, and the beak of the successful
fisher all the same overtakes the prey – if not this, so the next fish. But
what such destruction of tens and hundreds fishes means compared to tens of
thousands of survived ones moving for spawning?
Travelling in the river, eversmolts meet other representatives of freshwater
fauna of New Zealand. In the lower reaches of the river benthonic layers of
water are occupied by other fishes – by native thick-lipped carps, large and
rather peaceful herbivorous fishes. Like eversmolts, they lead their origin
from the nonnative fishes introduced to New Zealand in historical epoch: they
are descendants of a carp. But in due course of evolution these fishes have
changed strongly enough in comparison with the ancestor and lead absolutely
different way of life. These fishes do not love life in lake with stagnant or
slowly flowing water and prefer to live in fast current. Body of thick-lipped
carp has streamline shape; it is completely different from its sluggish deep-bodied
ancestor. Flattened head reduces the resistance to stream of water, and sucker-like
mouth shifted downwards helps to attach to stones. Mobile fleecy lips allow
fish scraping from stones algal films – the basic food of this species.
Living in different parts of the world, algae-eating fishes display similar
features of behaviour. The more fish depends on algae as a food source, the
more furiously it behaves relatively to congeners and the more extensive is
its individual territory. Thick-lipped carps are closer to the end of such impromptu
scale: these are selfish individualists changing anger for favour relatively
to their congeners only in courtship season.
The upper lip of this fish is divided in the middle to two halves which can
move both in coordination and independently from each other, when fish scrapes
algae from substratum. Thick-lipped carps prefer coastal parts of river channel,
where the bottom is well lit by sunlight and on stones microscopic green algae
grow – it their basic food. If nothing breaks rest of these fishes, they simply
cling to stones, turning heads against current. Thus fishes keep against substratum
not only by mouth, but also by pectoral and abdominal fins, in which tips of
several forward rays jut out from membrane, forming something like tiny claws.
Each fish watches closely behaviour and movement of the relatives, ready to
rush in any minute for protection of borders of the territory. The owning of
“an observant point” on stone sticking out above the bottom or on snag is the
important requirement to territory which is occupied by fish. Such place serves
for submission of visual signals to relatives. The fish looks especially favourably
at such place when it is well lighted.
Some individuals of thick-lipped carp differ from other ones: on the top blade
of their tail fin long thread with well appreciable cross strips of black color
grows. Fishes with threads on tails are males, and each of them supervises the
territory especially zealously. Long threads of tail fins wave in current, submitting
warning signal to other males. But female is willingly admitted to the male’s
territory: in spring at these fishes the spawning season begins.
When female of thick-lipped carp lack of long thread tail, appeared in male’s
territory, he has turned to the gallant groom: having gone down from stone,
male has swum up to the female and has stopped in current near to her, having
stretched fins and displaying to her thread on tail. It seems female likes him:
she folds back fin slightly, expressing the submission. Male continues courtship:
keeping side by side with female, he began cracking and clicking with the help
of pharyngeal teeth, which have turned at this species to the sound-reproducing
device exclusively. Female behaves modestly – if she will not express submission
to the male, it will be recognized as an encroachment to the territory and then
instead of courtship games she would get impact by strong snout in her side.
She holds fins pressed against the body and replies only with rare clicks to
male’s courtship song. It is obvious, that female accepts male’s courtship,
and he begins the following element of courtship display: male creeps on the
stone, moving pectoral and abdominal fins one by one. He has crept forward a
little and has stopped in front of the female, turning by side and showing to
her his bright and widely stretched fins. It seems he managed to find suitable
female for this breeding season. But external circumstances rush into measured
and constrained life of thick-lipped carps in the most unexpected way.
At first eyes of native thick-lipped carps turned in sides and upwards a little
notice separate small fishes, swimming quickly above them. But within several
minutes conditions in the river change completely: eversmolts swim upstream
like a continuous flow, and their shoal is stretched across the whole width
of a channel. In addition the shoal of fishes becomes denser every next minute.
Each thick-lipped carp busy with courtship games receives some appreciable impacts
in sides and fins – eversmolts moving to spawning in continuous mass run into
them. Everything is changed – now there is no trace left from peace and quiet
conditions having to courtship games. Fishes constantly feel waves from movements
of numerous eversmolts, and motley sides of these fishes flashing before their
eyes completely close the field of view and transform world around into mad
dancing of colors and flashes. Thick-lipped carps having got in school of eversmolts
can hardly make a way for themselves in live mass of these fishes. They simply
slip from stones downwards, on the bottom, and wait the end of pass of this
shoal.
Gradually the main number of eversmolts has swum past, and sun rays reach river
bottom where thick-lipped carps hide again. Only separate small groups of fishes
remained behind the main shoal are swimming by them now. But thick-lipped carps
do not hurry up to leave their shelters: they see how highly above water silhouettes
of birds following the eversmolt shoal sweep over. This danger passes gradually
– birds fly off further, or simply return to their territories, having taken
advantage of benefit of short-term easy fishing. Approximately half an hour
after a leaving of eversmolt shoal is passed, and life of thick-lipped carps
completely returns to accustomed train and fishes swim away to their places,
but not all do it. The female so actively courted by male, has moved away somewhere,
and now he needs to make new efforts to involve new female ready for spawning.
Therefore thick-lipped carp male continues courtship display with the double
eagerness. Now he has dark green colouring with bronze shining. To display itself
at its finest, he keeps at top of stone as on a throne, and around of him the
carpet of filamentous green algae waves. Having stretched red fins, it is clanged
against the stone with their help. His back fin is widely stretched and in sunlight
its red colouring is appreciable, and the long thread of tail fin waves in stream.
Male displays itself not only to females. For other males its colouring and
pose represent a challenge to a duel or the warning of probable repulse which
it can give the contender which is not commensurating force and ambitions. And
it is not necessary to wait for the answer to this challenge for a long: in
provoking affinity from this male the competitor appears, being also in fine
physical shape. Small and weak males prefer to steer clear of such handsome
male, but this competitor is a large and strong fish which would like to take
for itself a part of possession of this male. But fight is usually preceded
with an estimation of physical opportunities of the contender – it is a ritual
which allows avoiding putting injuries to each other by battling contenders.
Noticing the contender which has broken borders of his territory, male has gone
down from the stone and has swum towards to it. Having turned muzzles against
each other, fishes have begun “negotiations” – both males began uttering series
of clicks, simultaneously frightening each other by stretched fins. The owner
of territory turned its side to the contender, continuing uttering “trills”
with pharyngeal teeth, and has sharply waved tail, producing a wave to contender’s
side and enabling it to estimate his force. But the contender has answered it
absolutely unusual way: breaking “the code of honour”, it did not begin waving
tail, but at once has emerged and “sat” on the next stone. It tries to take
at once a place indicating its superiority. The answer to it from the side of
the territory owner appears simple and predicted: he has overtaken the impudent
contender, pushed it from its place with ramming impact of a snout and has forced
to swim down to the bottom, pressing it by own body from above. Accompanying
its movement with the series of clicks, he has driven the contender to the border
of territory, pushing it from time to time by snout in sides and tail. At the
border of his territory he has not missed an opportunity of displaying itself,
having stretched fins and making sharp movements by tail aside the contender,
and then turned around and has majestically swum to his stone “throne”, expecting
for the attention from the side of females.
In colony of penguins life takes its normal course. In life of many members
of colony there was nothing new, and among young birds one more breeding couple
has appeared, which should nest for the first time. Also there is one more good
event: it seems widowed female expelled from her own dwelling has found a new
husband for herself. She has expressed the great interest to young single male
which was just busy with digging of new hole under flat stone, which edge now
hangs above an entrance like a roof. Work is not completed yet, but it is already
visible, that he will make a good dwelling. It will take only two days of work
– he will turn to enviable groom with a fine apartment. Lonely female was frequently
late near his hole, and this male did not drive her away. Maybe, at first he
was too busy with the work to pay attention to his associates, but later the
presence of female became an additional stimulus for him for continuation of
the building. He related neutrally to the female, but did not beat and did not
drive her away – and it is already a good sigh as itself. And the female gradually
began to behave as if he already became her nesting partner: when male left
for fishing, female remained near his hole and displayed aggression to neighbours,
protecting the space around of the hole. Having returned, male continued digging
a hole, and female simply walked beside and cried loudly at relatives appeared
nearby.
In human epoch forests of New Zealand have ceased to be safe for ground-dwelling
birds, especially if they lost their ability to fly. And Neocene fauna of islands
bears on itself heavy burden of human activity – it includes numerous descendants
of terrestrial mammals, and among them there are also predators.
Vanity of penguin colony was broken by alarm signal, and penguins have habitually
run up to their holes. Lonely female has got into the hole unfinished yet –
male has left to feed, and nothing prevents her to hide in his hole. The wood
litter and dry fern fronds rustle under paws of sluggish and clumsy creature.
Nevertheless, threat is quite real and not illusory – towards the colony of
penguins New Zealand unbadger hobbles. It is sluggish, but strong and ruthless
predator capable to be very quick if necessary. It is smaller compared to ruacapangi,
but it does not make it less dangerous opponent: maybe, it loses to ruacapangi
in speed, but wins in force. Using strong paws, it can turn out the stones protecting
an entrance to a hole, dig it out and eat the penguin cornered. The passive
defense saving from ruacapangi is disastrous here, and a pledge of success in
confrontation to this animal becomes active defense which penguins are able
to make to some extent.
The behaviour of New Zealand mountain penguins living in places, inhabited plentifully
by predators, has appreciably changed in comparison with behaviour of their
ancestors living in rather safe world of islands and ocean coasts.
New Zealand unbadger wanders in colony of penguins. It sniffs at holes and tries
to pick off by claws stones near which they are dug out. It succeeds to scratch
some little stones from the ground when it has felt as someone has strongly
pinched its tail. Having screamed, the beast turned around and has seen near
to itself a small group of penguins. They are obviously not going to hide. One
of them has called loudly and belched semidigested fish, having spat it in muzzle
of predator. The others have caught up its cry and unbadger has shaken its head
– so loud was the cacophony of voices of penguins. Then in its wool some more
some pieces of semidigested fishes hit. Now cries sound from everywhere: penguins
leave holes and call loudly, surrounding the predator. Unbadger has grinned
and has clicked teeth – hunting is obviously broken, and these strange creatures
behave somehow unusually. And at this time it has felt sharp pain in hip – one
of penguins has rushed to it and has bitten it, having squeezed beak strongly.
In beak at this kind of birds there are two tooth-like outgrowths, and it makes
its bite even more painful. The beast turned around and its teeth chattered,
having tried to get the offender, but from this movement the penguin has flown
aside and has rolled on the ground, holding in its beak flock of beast’s wool.
One more penguin has rushed to the enemy from behind and has seized its skin.
Bird’s beak has broken through the beast’s skin, and on its wool the spot of
blood has appeared. The animal is surrounded with those ones which it expected
to catch and to eat, and it is obvious, that good luck is not on its side now.
Penguins pinch its sides and tail by beaks, jumping aside when it is turning
to them by muzzle. In wool on its hip the spot of blood flows and unbadger feels
acute pain in wounded place. The male penguin, to which lonely female pays attention,
has had time to return to the colony just in heat of battle and at once has
joined in struggle against the enemy. He managed to pinch a predator strongly
for some times, and his voice has joined the common cacophony.
Shaking its head, unbadger recedes. The moment of suddenness is lost, and now
it had to lick its wound somewhere in shelter, instead of feasting. In due course
of its distance from the penguin colony their battle cries become more silent:
the colony gradually returns to habitual life. Such incidents, besides minuses,
have also small pluses: joint defense against unbadger has even more rallied
a couple of penguins. Female has cautiously approached to male, has sat down
in front of him and has touched his beak from below by her beak. The answer
was immediate and predictable: male has opened his beak and has bent head downwards,
allowing female pulling out fish from his gullet. After that it is already impossible
to name female as lonely one – the pair of penguins has contracted the conjugal
unit. As a sign of trust male has cautiously touched feathers around of female’s
eye and has cleaned them. Then he has inclined head on one side, and female
has cleaned a mote from his plumage. Now work on a hole will go much faster,
and it will be possible to begin nesting soon. And nesting and rearing of chicks
will show, as far as successful there is this married couple.
Changes in a nature stimulate courtship behaviour of animals even if it demands
the application of significant efforts. It takes place so at eversmolts – small
fishes which continue travel to the upper course with amazing persistence. During
the travel in colouring of males changes take place: they become velvety-black,
and on their backs now irregular-shaped spots redden. The great shoal entered
the river from lake has gradually thinned: feeling a smell of native inflows,
a part of eversmolts has already left the common school. Ones still remained
and continuing the travel to upper courses need to overcome many obstacles.
More often these are river rapids which should be stormed for a long while.
Maybe, any large salmon would easily overcome such rapids in single jump, but
from small eversmolts significant efforts are required for the decision of this
problem. The school of fishes stops below the rapids, and with each minute their
number becomes larger due to the individuals running after the main school.
In breakers of water under rapids spotty and black backs flash, and some fishes
jump out of water vertically, as if trying to estimate the situation. When the
number of fishes becomes too great, storm of rapids begins. Eversmolts begin
jumping in groups over rapids. They squeeze between stones, where current is
weaker, or try to make two-three strong jumps in succession to overcome rapids
quicker. Some fishes try to swim upwards in jets of water against current, but
such ones, as a rule, are carried away downwards, and they had to begin anew.
Some fishes succeed to overpass rapids, but, having grown weak, they can not
keep speed in current and the river carries them downwards. The jump of one
fish may serve as stimulus for other fishes, and sometimes one jumping eversmolt
is followed by some more ones and after them up to fifty fishes jump in total.
Such live wave as if is broken against water, but some fishes all the same succeed
to overpass rapids. Above rapids, in the places behind large stones protected
from fast current tens tired fishes managed to overcome this obstacle gradually
accumulate. When to them other lucky ones swim up for rest, in places convenient
for rest small conflicts flash, but even they may be enough to push some individuals
out back in stream. Then they should spend the rests of forces to break back.
And some especially unlucky fishes are washed downwards, and they had to spend
forces again, overpassing river rapids.
Storm of thresholds gradually comes to an end. Current carries away losers –
the stunned, weak and dead fishes. Some of them have spent all forces for jumps;
current has simply broken head or backbone to other ones by impacts against
stones. And some fishes had never overpassed the rapids at all. Such fishes
cannot have any progeny and will be, most likely, simply eaten by predators.
Above river rapids the fish school continues its movement. Tired fishes keep
at the shoaliness along the riverbank, where current is not such strong. Silhouettes
of birds on the background of the sky force them to hide in depth, but do not
stop their movement to upper courses.
At last, travel of eversmolts comes to an end: they swim into the streams which
smell of water was embodied in their memory as soon as they hatched from eggs.
They are not alone in these streams: when these active fishes appear, small
tadpoles of rangitahi frog swim away in all directions and hide under stones.
Eversmolts are predators, and rangitahi tadpoles of suitable size become their
prey. But now everything in behaviour of eversmolts is subdued by the only purpose:
to have a progeny. At the stream shoalinesses males display their impressive
courtship dress: velvety-black with red spots on sides. Silvery eyes as if shine
on black background of colouring of male heads. Females, on the contrary, turn
even paler. The marble pattern on their sides vanishes almost completely, from
it only separate black spots remain. The number of fish increases, and it serves
as a push for the beginning of spawning.
In fact, it is all the same for eversmolt female, what male will make courting
to her. At these fishes breeding pairs do not form and spawning passes very
quickly. In the main, every male managed to reach up to spawning areas has proved
the suitability for propagation of the species, and any of them can be considered
as the best one from the female’s point of view.
Eversmolt males spread in regular intervals along the sites of a channel where
the bottom is covered with straight layer of pebble of small size. Each of them
signals to neighbours with its colouring, that the place is already occupied,
and banishes late males by impacts of snout into their sides. But, as soon as
near to male the female appears, it begins making court to her gallantly. Having
stretched fins, he stands side by side to female and begins shuddering with
its whole body, enabling her to estimate his force. If the female does not swim
away, male falls on bottom and begins scattering ground in sides with sharp
lateral movements of body and tail, digging a shallow groove in the bottom.
Female follows the male, laying eggs in this groove, and male at once impregnates
them and both fishes in common fill up a portion of eggs with pebbles. The only
element of parental care at eversmolts is a choice of pebble ground of the proper
size for the arranging of the nest. If the pebble grains would be too small,
the water carrying the oxygen will reach hardly to developing eggs. If they
would appears too large, it will be more difficult for digging out, and current
would simply wash up outside a part of eggs through intervals between pebbles.
Travel to nesting areas may be too expensive for eversmolts. As against the
majority of salmon fishes of human epoch, eversmolts can spawn for some times
in succession. But all the same the part of eversmolts perishes – from wounds
and simply because of irreversible changes in an organism connected with spawning.
Mature fishes, as a rule, are strong enough to recover from stress which they
endure during the spawning and the organisms of old and weaker fishes do not
sustain such test for durability and its degradation begins.
Having grown weak after spawning, eversmolts cannot resist to current any more.
They hide behind stones to defend themselves from the current washing them away,
and in such places tens small fishes gather. Males at this time already start
to turn pale. Red color vanishes at them especially quickly, and black colouring
gradually changes to grey. Females, on the contrary, restore spotty colouring
and become less appreciable on the background of stony bottom. It is important
for them, because after spawning eversmolts appear very vulnerable for some
time.
The run and spawning of eversmolts involve to mountain streams some local animals.
Almost the same took place at the salmon rivers of Eurasia and North America,
where bears, seagulls and ravens gathered to have a feast. At the rivers of
New Zealand this picture repeats, but with local colour: here “salmons” are
much smaller, and instead of bear New Zealand unbadger goes fishing. New Zealand
false raven, on the contrary, is much larger, than its continental analogue
of human epoch, and a role of seagull in some rivers is performed by New Zealand
mountain penguin.
Massive New Zealand unbadger is a rather sluggish beast, but even its quickness
is enough to hunt eversmolts restoring forces after spawning. Beast obviously
avoids bathing in cold water of mountain stream; therefore it prefers to hunt
from stones. It dexterously leaps from stone to stone, getting rather far from
the bank, almost to the middle of stream. Having leaped on large stone, unbadger
cautiously steps on it by soft paws, trying not to make superfluous noise. Having
walked to the edge of stone, beast has lain on stomach and began observing of
the fishes keeping under the covering of stone in small school, and has held
one paw ready for impact. Expectation was short: in one minute unbadger has
made one fast movement by paw and has snatched out an eversmolt from water.
Having pressed struggling fish against the stone, beast has seized its head
with teeth and has bitten its scull through. Having eaten meat from the backbone
quickly, it has thrown out the rests of prey in water and stands again with
paw ready to attack. During a half an hour it managed to catch one by one five
fishes and to eat them. And its success in fishing has drawn attention of feathery
lovers of easy prey.
Fishes have rushed in all directions and were hid, when on a surface of water
the shadow of winged creature flashed. Then loud wing flapping followed, and
on stream bank New Zealand false raven landed. Unbadger has looked back on it,
being obviously angry, because the appearing of this bird has scared away fish
which it hunted, and in two leaps has got over to one of the next stones, almost
at an opposite bank. Large black bird walks forth and back on land, glancing
to unbadger with its shining black eye. Having seen that the bird does not represent
any threat for it, unbadger has concentrated on fishing. Some minutes of waiting
have been crowned with success – it has snatched eversmolt out from water. When
the fish was fluttered, being pressed against the by beast’s claws, the raven
has quickened. It has flied up, in two strokes of wings has flown over the stream
and has attacked unbadger, trying to take away the fish caught by it. Attacked
unbadger, not letting out prey from under paw, has begun roaring, having forced
raven to fly up above stone and to land on next one. Hardly keeping on slippery
stone, the raven has cried loudly and has begun to flap wings, and unbadger
has fluffed up in return the white wool growing on its cheekbones, and has raised
tail, which trembled in air. Birds have too weak sense of smell; because of
it raven simply has not felt a disgusting protective smell which unbadger has
let out from special glands at the root of tail. To attempts of taking away
its prey from the part of raven it invariably answers by growl and demonstration
of grinned teeth. The warning is very obvious, and raven prefers to recede.
In itself the New Zealand false raven is rather successful hunter, but for the
clear reasons it likes to live by robbery of weaker predators. Nevertheless,
care prevails, and the bird makes reasonable decision to leave unbadger free.
The raven has simply flown to the next stone, landed on it and after several
minutes of waiting has dexterously snatched itself one eversmolt from stream
and began pecking it immediately.
Small eversmolts are creatures having many enemies. Frequently these fishes
are saved from extinction only with the considerable fertility. At this kind
of fish enemies are present at any stage of development, even when posterity
is not hatched from eggs yet. And the paradox is that eversmolts come for spawning
right into the home of their enemy. Grown up tadpoles of rangitahi frog are
large creatures representing danger to eggs of eversmolts and for their larvae,
at which yolk sac has not resolved yet.
In streams spawning of eversmolts still proceeds. But now the fishes that have
been late to spawning, ones that for any reasons were late during the migration
are breeding. Nevertheless, even they have chance to have a progeny.
Couple of eversmolts spawns at the bottom covered with small pebble. Some days
prior to them here rough spawning games took place, and this territory was divided
into set of the individual sites protected by males waiting for females. Now
the hullabaloo declined, and success in spawning depends only on the ability
of potential breeding partners to find each other. A competition to others males
is absent and male displays itself to the female. By powerful movements of tail
male scatters ground in sides, making a small groove for eggs, and female rushes
following it, laying eggs. Male fertilizes them, and fishes immediately bury
their clutch in pebbles. But they are not alone here. Involved with their movements,
the large rangitahi tadpole is swimming behind them. It is careful and keeps
aloof from fishes, trying to not come nearer to them before the proper time.
But when it hears characteristic silent knocking of pebbles stones under tail
of male burying the clutch, it rushes to fishes. Male just finished the burying
of eggs under pebbles, and the tadpole is already swimming after it, ready to
dig out the clutch. When eggs are spawned, female abandons male, and when the
last movement of tail to dig the clutch is made, male also loses interest to
its own posterity. Fishes do not protect eggs – their parental instinct is silent,
they have made everything provided by their behaviour for propagation of the
species. They swim off, being completely indifferent, gradually acquiring the
colouring characteristic for this species out of spawning time. And the rangitahi
tadpole began ravaging just dug nest, scattering smaller pebbles by snout and
dragging larger stones in mouth transformed to sucker. After several minutes
of its work at the bottom small hole was formed, in the middle of which orange
eggs wave. These fishes cannot hatch: the tadpole absorbs eggs, swallowing some
pieces at once, soaking them up by eternally opened mouth. Involved with its
activity, some more relatives swim to join its feast. Having finished with one
clutch, tadpoles dig out other nests of eversmolts and eat eggs. Sucker mouths
help them to take away the large stones, preventing to ravage fish nests. Only
the rests of eggs are carried by current from the dug out nests. But nevertheless
the part of eversmolt eggs will escape, having fallen deeper between stones,
and the new generation of these fishes will appear in stream to join the constant
flow of life.
After spawning eversmolts go through very difficult time. It seems, as if all
weariness which it has gone through during the travel to upper course of the
river at once falls upon every small fish, and at once all wounds received during
the travel begin to ache. Bodies of some individuals are covered with wounds
and the grazes received at the making of nest. At the moment of spawning nobody
had paid attention to these wounds – fishes had more important task. But now
all wounds have an effect. At some fishes wounds gradually heal, and ones are
less lucky – in wounds parasitic microscopic fungi have settled, covering the
wound with cotton-wool coating. Some fishes will not cope with infection and
will not survive even after the first spawning in their life. But the most durable
members of population can return to native places five, and even six times per
life. Eversmolts gradually leave spawning areas and move down to lower reaches
of the river. But it occurs not in huge shoals, but in small schools which are
not noticed at all by other inhabitants of the river.
Penguins also prepare for nesting. Pairs of birds spend more time in holes,
deepening them or making some repair of walls. In some days the first eggs will
be laid, and members of a colony will accept parental duties which they will
fulfill within approximately three months – while the brooding proceeds and
while chicks will learn to search for food independently. For now life in a
colony of penguins proceeds in former rhythm, under accompaniment of loud voices
of these small birds. But life in a colony is not insured from accidents which
can result in the most unexpected consequences.
The ground hoots from impacts of hooves: some adult ultradama deer run in forest,
being frightened by a predator pursuing them – by marsupial
pardus. Rattle of hooves comes nearer, and in colony of penguins panic
occurs. Short-legged birds run up in all directions, hide among roots of trees
or near stones. Some of them try to hide among ferns. Impacts of hooves against
the ground become louder with each second, and, at last, there comes an outcome:
one of huge deer runs directly across a colony of penguins. Probably, it has
not noticed it at all – for it the penguin settlement differs only a little
from the forest around it, and it has crossed a colony in some leaps. But for
penguins the consequences of this accident are too well appreciable: hooves
of the beast have destroyed some holes. And at the pair occupying a site in
the center of a colony, the hole is destroyed completely – it cannot be dug
out any more. In ovary of the female the first egg already began to ripen, but
now it could not be laid. To say more exactly, this amicable and strong pair
of penguins knows, how it is possible to become owners of new convenient hole
very quickly – it is necessary simply to look for themselves a good hole which
weaker pair owns and to expel them. Or it is possible simply to seize the moment
when the hole is empty and to occupy it.
The pair formed by widowed female and young male becomes an object of an attack.
Their hole is well fortificated and represents a tempting prize for aggressors.
And this pair does not behave yet so harmoniously, as pairs keeping together
already for some nesting seasons. Therefore they frequently make the mistake,
due to which usurpers of their house have taken advantage: they went for feeding
approximately in the same time, and also separately from each other. And the
hole staying empty for about two hours became easy trophy of the pair which
has lost their house.
Male has returned from fishing the first. Having approached to the hole, he
has found out near it a couple of birds which he saw very far from his dwelling
before. And this pair was obviously engaged in establishing of relations with
neighbours. Having not paid attention to it, he was directed to the hole which
he has dug out itself. Screams behind his back have interrupted immediately,
then he has heard sound of steps coming nearer, and finally impacts of two beaks
at once have fallen upon his back. These two birds rushed simultaneously to
him with loud screams and began pecking him, driving away from the hole. He
has tried to protected himself, but he had been tumbled down on the ground and
both birds began pinch him painfully, and then the usurper male has driven him
away, screaming and pecking him. Fight appeared crueler than daily conflicts
happening between neighbours. If in those cases everything is limited only to
cries and displaying of the body size, ritualized in addition, but now there
is a real fight, and the main prize in it is an opportunity to rear the posterity
in this season.
When female has returned, she has seen how the extraneous pair of birds absolutely
freely plays the masters in the hole which she only recently began to accept
as her own one, and her male wanders beside, and on his side traces of blood
are appreciable. When female has tried to enter her hole being her property
even the morning, aggressors attacked her, screaming loudly. Male has tried
to help her, but one of aggressors has simply pushed him aside from the female
and has continued to beat her. Two large adult birds operate as a team against
owners of the hole. They beat each of birds by turns, not giving another bird
to come to help each other. The neighbouring pairs do not pay attention to this
conflict: while borders of their territories are not crossed, they are simply
indifferent spectators. Only when fight proceeds at the border of the territory
of the neighbouring pair, birds go to protect their possessions. But neighbours
are not helped by anybody – they remain face to face with aggressors. For other
birds there is actually all the same, which pair would be their neighbour on
results of the conflict – the already familiar pair, or any another one. While
borders of private territory of pair are not broken, they would not begin to
interfere with another’s conflict.
The result of struggle for vital space is predictable – aggressors supersede
a pair of penguins from their own hole. But it is not enough of it for fastening
the success: aggressors simply expel the homeless birds from the colony. Hackneyed
birds with traces of blood on their plumage cannot show worthy resistance to
aggressors, and from the side of neighbours, in whose territories they appeared,
birds are waited only with an additional portion of beak impacts. As a result
they appear at the edge of the colony, hackneyed and grown weak. The world around
has suddenly changed for this pair: they have lost a habitual society of neighbours,
safe dwelling and fishing areas. Now their survival is under the question in
addition to the opportunity of nesting in this season.
The pair of penguins has abandoned the colony. It is a very risky step for birds
which have got used to live being surrounded by their congeners. But the even
worse circumstance is the absence of neither shelter, nor the society of relatives
capable to render protection and support to them in case of need. Lack of neighbourhood
of relatives, runaway penguins are afraid of literally everything – easy rustle
from the lizard creeping among ferns or flapping of bird wings among branches
of trees forces them to rush to roots or to dense fern thickets in searches
of protection. The penguins expelled from a colony walked to the lake shore
and now walk along the bank of river flowing from it. They do not leave far
from water to have an opportunity to feed when they will feel famine. They have
chance to survive – along the riverbanks small colonies of New Zealand mountain
penguins frequently exist, and sometimes there are same “tramps” – lonely individuals
or breeding couples. But usually the destiny of such birds is unenviable: too
many predators live in forests and near the coast of reservoirs, for which lonely
penguins represent easy prey.
Looking back against each other, penguins lag along the riverbank overgrown
with ferns, bushes and low trees. They are good walkers, but walk clumsily,
jogging from side to side on short legs, and frequently stumble against tree
roots. From time to time birds listen, hoping to hear somewhere in the distance
voices of congeners. But they did not manage yet to find out the signs of their
presence. And their own presence is revealed and they are watched already by
local predators. In rich branches of one tree the pair of New Zealand false
ravens is hidden. These birds are able to hunt small ground-dwelling animals,
and penguins, lagging along the riverbank, represent easy prey. These ravens
form a breeding pair which has perfectly fulfilled tactics of a joint attack
to small animals, and now they are ready to attack penguins. Penguins do not
look in crones of trees, and therefore do not notice yet the threat from above.
Female perfectly knows habits of penguins, therefore she has left a role of
drover to her male, and has flied up, has flown behind the penguins and, having
overtaken them, landed on the ground between them and the riverbank. Having
seen her, penguins have rushed away, but their way had been blocked by male
raven which has terribly clicked its white beak. Pair of penguins against pair
of ravens – their position is not so hopeless: the lonely penguin would be killed
at once and here the certain opportunity to escape still exists. It is more
difficult to pursue two penguins, rather than one. But another thing is much
worse: female raven has cut off the escape way to the river, and now penguins
should save their lives on land, where they feel like not as confidently and
easily as in water. But they have two advantages compared to ravens – low growth
and skill of hiding. Therefore penguins, having seen that the way to water is
cut off, have tried to hide in ferns. Using this dexterous move they have deprived
ravens of advantages of an attack from air. Ravens cannot fly up – ferns prevent
them to see penguins. Only casually rocked fern fronds allow predators to guess,
where penguins hide. Having bent down, ravens wander among ferns, trying to
find out penguins. And penguins are skilled in hide-and-seek play. They simply
lie among plant dust and stay motionless. From time to time one raven or another
raises head above thickets and looks around, trying to find out penguins. But
it is uneasy to find them: camouflage colouring has reliably hidden them from
predators. Penguin female lies on the ground, having nestled against large fern
and does not move, even when the raven walks near her. Only slightly opened
eye of bird watches how the raven walks very close. Penguin female has not moved
even when the claw of feathery predator has scratched the ground fast beside
her wing. Her male is somewhere nearby, but he also has hidden. Shadows from
trees crones and fern fronds help penguins to disappear from the sight of predators.
Due to skill of hiding penguins succeed to deceive ravens – having not noticed
them, feathery predators have passed by, and now penguins appear behind them.
Now at them the opportunity to escape has appeared, and both penguins have almost
simultaneously rose and have run to water. Thus they certainly have given themselves
out, and ravens, having heard them, have rushed to chase prey. Two huge black
birds have flied up above ferns and have begun hovering in air. While penguins
run among ferns, ravens have fewer opportunities to find them. Small birds intentionally
foul the trail, changing direction of run. Ravens win in speed at the direct
distance, but now they should constantly change the direction of flight, therefore
they are in equal conditions. A small part of the way between forest and riverbank
appears critical for penguins. Here ferns have receded to the forest shadow,
and penguins should make the way through thickets of high coastal grasses. For
flightless birds of small growth this is a very difficult task, but also for
ravens it will be impossible to catch them from air. Black birds are compelled
to land in grass and to continue chase for penguins at a run, but good luck
has already smiled to penguins. Having made the way through thickets, they have
felt under paws fenny ground – it means water is already close to them, and
in water there is an escape from ravens for them. Some more steps, and feet
of penguins slosh in water. Having rushed forward, they have crumpled marsh
grasses and have got out in water. Feathery predators have missed prey. The
pair of ravens hovers above the river, and birds see, how two silhouettes of
penguins slide in water. New Zealand false ravens are able to hunt on land successfully,
are able even to catch fish from stones, but they feel like not so confidently
in water and are not ready to continue the chase for penguins in place where
they feel so easily and freely.
Male penguin has emerged the first. He was put out from water, has inhaled fresh
air and has cautiously looked round. He has seen two black silhouettes of large
birds above the forest in heavenly blue, but whether these ones were the same
ravens or any other ones – it doesn’t matter anymore. Near him the female has
emerged. They are still together and vital circumstances did not manage yet
to separate them, despite of loss of house and company of congeners. Right now
they managed to avoid danger of death. It is already good, but it is not enough
yet for them to look confidently in the future. It is too indistinct now at
this pair.
Male penguin has dived, and in some seconds in sunlight silvery sides of small
fishes, which he has pursued, have flashed. Female has taken a deep inhale and
has dived, joining the hunting. They are too silly to reflect on the future,
and live only by present moment, accepting everything happened to them as is.
The pair of penguins expelled from their colony wanders along the bank of the
river flowing from lake. And at the other edge of lake the river flowing down
from mountains turned to the migration way for live creatures again, but they
already move in opposite side. Tens long-bodied creatures with muscled tails
gather to schools and swim downstream. These are rangitahi tadpoles which have
spent some years in cold mountain streams, feeding on algae and small invertebrates.
They prefer traveling at night when they are threatened by lesser number of
predators. Small groups of rangitahi tadpoles reached the maximal size gather
in river channel to numerous schools and in common swim down to the lake to
finish there their life cycle. For them it is a one way road: no one individual
will return to the stream where almost the whole its life had passed.
Rangitahi tadpoles are in the best position compared to eversmolts which shortly
before it swam upstream for spawning to mountain streams. For eversmolts the
watercourse was one of numerous obstacles, but it only helps tadpoles to migrate,
therefore they can reach the lake, expending only few efforts. Tadpoles begin
migration at night, and in the morning in the river large schools numbering
hundreds individuals already swim.
In lower reaches of the river migrants swim through possessions of native thick-lipped
carps. But the relation to them on the part of these fishes is absolutely different,
than to eversmolts. For these fishes eversmolts were only a certain incident,
an annoying obstacle for fishes busy with courtship games or spawning. And tadpoles
with their sucker mouths cause aggression in these fishes: native thick-lipped
carps perceive them as food competitors though during the migration tadpoles
already stop feeding.
The school of tadpoles migrating to lake is swimming near the bottom. It numbers
some tens individuals of absolutely identical age of five years. They differ
only a little from each other in size, that reflects just a difference in conditions
of life in different streams and rivers. Suddenly tadpoles have felt sharp abrupt
sounds with their whole bodies – these are the series of clicks uttered by thick-lipped
carp. Large male of native thick-lipped carp has stretched back fin and has
rushed towards to them, chirring threateningly by pharyngeal teeth. It shudders
with the whole body, uttering warning sounds, and some tadpoles appeared close
to the fish, have swam away, but their place was on the spot occupied by other
ones. Thick-lipped carp has rushed to the congestion of tadpoles and began to
strike them by chaotic impacts of its sides and tail. But the stream of the
tadpoles, swimming towards it, does not decrease, and many of them are large
enough to repulse it. But they do not care at all of self-defense, and impacts
which native thick-lipped carp puts to them, remain without any response. They
have a purpose in their life, and they are too strongly subjected to it to distract
to such casual meetings.
Riverbanks extend and then completely vanish in bluish-green haze. Cool river
water gradually becomes warmer – rangitahi tadpoles have reached the lake. Having
felt changes of temperature of water, tadpoles begin to “yawing”, searching
for places with the warmest water. Having got into the lake, schools of tadpoles
stay for some time in thickets of plants in river mouth, and then begin to move
along the shore, searching for shallow gulfs where water gets well warmed by
rays of spring sun. It is vital for them – they have very short time of further
life, and they should fulfill the parental duty and only after that their life
cycle will be finished.
In some sense rangitahi tadpoles are similar to mayflies. In absolutely the
same way, as these insects, rangitahi frogs spend the most part of life in a
stage of aquatic larva. The adult stage both at mayflies and at rangitahi frogs
is ephemeric and serves only for breeding, which is followed by the inevitable
death. But before eggs will be spawned, rangitahi tadpoles should undergo metamorphosis.
The stay in well warmed water accelerates this process, therefore in gulfs numerous
schools of these creatures gather. Large tadpoles, more similar in size to fishes,
swims in warm water at the surface. They literally on the spot undergo the metamorphosis.
The buds of extremities formed during the life in mountain streams, have started
to increase, and at tadpoles already in the first days of life in lake rear
legs, and after them, with small backlog, front ones develop.
In due course of metamorphosis bodies of these creatures undergo further changes
– the slight trace of neck appears, head extends, eyes become convex. At the
future frogs legs grow larger and now outlines of their bodies are more similar
to typical for frog. The only thing that is still differing young rangitahi
frogs from frogs of other kinds is a tail. It serves as a stock of the nutrients
necessary for metamorphosis and breeding. In literally noticeable way tails
of rangitahi frogs grow thin – muscles degrade and bones literally dissolve.
Muscled tail becomes similar to wrinkled sac of skin, quickly decreasing in
size. But at females stomachs are increased simultaneously – eggs quickly mature.
Having left the mountain rivers, rangitahi tadpoles have got into the dangerous
world. In cold water of mountain rivers only few dangers waited for them – they
could freeze, if the rivers became covered by ice, but predators in mountains
were rather rare. And here, in warmer lake water, they should meet other dangers.
Long body slides under water near to the surface. It is covered with small scales,
with a simple pattern of narrow white cross strips on dark grey background.
The small flattened head moves from side to side, putting out the thin doubled
tongue, and small eyes look, but not blink. It is a marshland aotearophis, the
New Zealand endemic kind of snakes. As against many other species, this creature
is the descendant of natural settlers of archipelago. It descends from sea snakes
which began to develop fresh waters, and then also wetland habitats of the islands
already after the ending of human epoch. As well as it is necessary to the descendant
of sea snakes, marshland aotearophis is poisonous. Its poison is an adaptation
for hunting cool-blooded prey; therefore it has great killing power. But the
snake, having such weapon, prefers not to enter conflicts to other inhabitants
of lake. Also the reptile prefers to keep near to the shore and at a surface
of water where is warmer.
Some New Zealand mountain penguins are swimming under water, quickly flapping
wings. Having seen the snake, birds simultaneously dive and try to swim out
far away. Aotearophis does not attack penguins – adult birds are too large for
this snake, and additionally marshland aotearophis is a specialized herpethophagus,
obviously preferring catching false salamanders and lizards of suitable size.
Penguins are not a prey for this reptile, but all the same they are afraid of
it and prefer to keep the safe distance.
Jutting out its tongue, snake gathers with its epithelium the molecules of the
odorous substances dissolved of water. It feels that somewhere nearby it is
possible to find a lot of prey: the reptile smells rangitahi tadpoles. They
a little than differ from false salamanders, therefore marshland aotearophis
snakes hunt them in regular way, when tadpoles go down to the lake for metamorphosis.
The snake heads for shallow water and soon swims into the shallow gulf where
the numerous group of rangitahi tadpoles has gathered. Warm water in gulf has
forced snake’s heart to beat faster, and the reptile has felt famine much clearer.
It feels a distinct smell of prey: the great school of rangitahi tadpoles swims
at the surface. Pleasant heat has spread in the body of snake and the reptile
began hunting. It has cautiously emerged aside, in thickets of marsh plants.
Having inhaled air, the snake has dived and has swum above the bottom, wriggling
smoothly. Its eyes slightly turned upwards distinguish the school of large fish-like
creatures swimming at the surface of water. They are obviously not frightened
yet.
As if a miniature fantastic water dragon aotearophis has come up from the bottom,
and its head has risen directly in the middle of school of tadpoles, rushed
in panic in all directions. One tadpole, however, did not manage to escape,
and now it is struggling in teeth of the snake. Its movements weaken with each
second, and soon only tip of its tail quivers in last spasms. The teeth of aotearophis
stuck into its body have injected into the body of prey strong poison which
has almost instantly killed prey of the snake. Hunting is completed, and the
reptile, wriggling its body, is swimming to the shore, frightening tadpoles
swimming in panic in all sides and squeezing into the thickets of aquatic plants.
But now just nothing threatens to them: the predator has received the prey and
is not going to attack yet. Aotearophis has crept into shallow water, has turned
its body in several rings, and began swallowing a tadpole, having raised head
above water. It had taken at the reptile no more than ten minutes; then the
snake has got out to the land and has crept to search for place in coastal thickets
well heated up by sunlight.
Some more days passed. Rangitahi tadpoles have already almost finished metamorphosis
and have turned to small black-and-white frogs with the reduced tails, swimming
at the surface of water. Due to their behaviour and shape it is possible to
think, that they literally hasten to live: rudimentary larval tail has not disappeared
yet completely, and rangitahi males already began to share a surface of water
into set of small territories. Having chosen for itself the place on the surface
among thickets of aquatic plants, male begins to drive other males away from
it, distinguishing them by smell. Some males also start to give sound signals
– squeaky croaking similar to whistling. At first these are abrupt and dissonant
calls, but gradually the concert of frogs becomes much louder. It is enough
for one male to start calling, and its neighbours join it, and their calls sound
all more harmoniously at every new attempt. Hearing these calls, individuals
at which for any reasons metamorphosis is late, accelerate their transformation.
Females gradually start settling at the possessions of males, being evenly distributed
on the surface of gulf – so there will be more likely to meet male and to avoid
a competition to relatives. Everyone prepare for the magnificent denouement
in which life and death will interlace in single dance.
In the early morning of one spring day the culmination of this performance begins.
When the sun appears above the edge of a mountain ridge, rangitahi begin singing.
At first separate rangitahi males begin its song. They start uttering sharp
abrupt calls similar to whistling, but their concert is dissonant and gradually
calms down. After the first wave of voices rangitahi males as if synchronize
the voices: they utter the muted sounds similar to ticking. Males try to fit
into the rhythm set by relatives. If in water there are two “synchronized” males,
the third male will join them much more willingly and will fit to their rhythm.
And when some males “tick” synchronously, the rhythm set by them is adopted
quickly by the other males around them.
The excitation of males grows gradually. Ticking becomes louder and louder until
one or two males begin uttering the courtship song characteristic for this species
and similar to acute whistle. And then the silence is literally blown up with
simultaneous calls of hundreds males. They call synchronously, keeping a rhythm
given in time of “ticking” phase of courtship songs. At this time lake shores
literally shiver from their voices.
The noise created by singing rangitahi is simply deafening. During the courtship
concerts of rangitahi even beasts are afraid to come to the lake, being frightened
of their voices, and the birds living at the sites of lake shore chosen by rangitahi,
simply stop their songs – their voices are all the same not audible against
the background of frog concert. The expenditure of energy for this performance
is simply enormous. At this time rangitahi frogs eat of nothing, and they cannot
do it at all – the digestive system of adult frog is strongly reduced and gradually
degrades. Their existence is a single ticket, and the whole short adult life
of rangitahi is dedicated to the only purpose – to leave a progeny. Males sing
in unison, and between females there is a competition for the best groom: they
gather around the most vociferous males, pushing away each other. If the competing
females do not hurry up to leave, jaws are used and due to aggressive behaviour
the strongest female literally clears away a place to herself near the male.
Gradually rangitahi females spread in more or less regular intervals near males.
Bellies of females are full of eggs: if males spend energy exclusively for courtship
display, at females the resorption of tail provides mainly the development of
eggs. Rangitahi female, having chosen suitable male, literally creeps under
him, and male automatically clasps her by forepaws across the body. At this
moment he stops croaking, and only utters acute squeak when any of neighbouring
males tries to attempt on female already chosen by him. Having reached the culmination
to approximately three or four hours p.m., the courtship concert of rangitahi
gradually stops to the sunset.
When the pair of frogs has found each other, the most important stage of all
this action begins: it is the egg spawning. Rangitahi female lays a lot of small
eggs which are at once impregnated by the male. Within several hours after the
appearing in water eggs inflate strongly; because of it the surface of water
in places of rangitahi spawning resembles kissel. However, rangitahi frogs attenuate
and exhausted by courtship ritual do not abandon their clutch. Their further
life will proceed not for long, and their last efforts are directed to protecting
the future posterity.
The next morning the sun shines numerous clutches of rangitahi frogs floating
in water in large slimy lumps. Adult rangitahi frogs, having turned paler appreciably,
stay motionlessly atop of their clutches, coming to life only at the approach
to their future posterity of any animal which can threaten something to the
future tadpoles.
The young New Zealand mountain penguin swims along the lake shore. This one
hatched the last year only and until the present days had never heard voices
of rangitahi frogs. Therefore yesterday it had stayed till the whole day on
land, suffering from famine and being afraid to come nearer to lake because
of calls of these frogs. But closer to night voices become silent, and the morning
has met the inhabitants of lake with saving silence. The penguin has managed
to catch some fish and was sated, and when he has swum along the shore, its
attention had been drawn by lumps of rangitahi eggs waving in water near the
shore. The penguin has swum up closer to rangitahi spawning area, has inhaled
air and has dived. For some wing flaps it appeared near one of egg lumps, and
has noticed from under water silhouettes of two frogs inside the mass of developing
eggs. While it was at the some distance from clutch, frogs remained motionless.
But it has swum up closer and has tried to peck up some eggs. Both silhouettes
of frogs came in movement immediately and were directed to it, making the way
through the mass of eggs. One frog has got out the first. It wasn’t stopped
by the expressed superiority of penguin in size. With fanatical purposefulness
the rangitahi frog has rushed on it and has seized bird’s leg by its own paws.
The penguin has felt, as its leg as if appeared squeezed in vice: so strong
was the grip of this frog. Having been frightened from unexpectedness, the penguin
began jerking its leg, trying to throw out frog from itself, and it succeeded
to do it not at once. The frog dumped from its leg turned to it again and has
swam, having extended front legs forward. The penguin has swum aside, and the
frog instantly turned around, has swum up to its clutch and had got into the
middle of egg mass.
The penguin didn’t like the taste of frog eggs, and it has simply begun teasing
frogs which sat in their clutches. It swam up, touched eggs by beak and waited
until the frog will get out of clutch and then swam away, not giving the amphibian
any chance to seize it. It succeeded to do it for some times, but one frog has
managed to cling strongly to its wing and did not let it off for long, though
the penguin shaken its wing and even tried to peck the frog. But, as soon as
it has left from the protected clutch, the frog has let it off. Soon game has
bored the penguin, and it has returned to the colony.
This penguin has place which it may regard as its home, but some of its relatives
are not so successful. The expelled penguins wander in thickets, still not finding
a society of relatives. They keep near the riverbank where it is easier to find
food and to hide from the enemy, and spend nights in any casual shelters. Time
of nesting has already come: in the colony left by birds the first eggs already
have appeared. And at this pair the opportunity of nesting in this season is
very questionable now. If birds will not find the suitable place for habitation
and the making of nest, they will have to refuse nesting. And then it is possible,
that family of these birds will simply break off. But the intelligence of penguins
is not so high to reflect on the future. They simply live in the today’s afternoon,
realizing their vital needs. Simply now, lack of the society of the congeners,
both birds of this pair keep much closer to each other and try to do everything
together.
The pair of penguins in common dives for food in the river flowing out from
lake. In water they feel like easily and freely, but they should struggle against
current which was almost not felt when birds lived in colony near the lake.
Penguins are swimming under water together, flapping wings, and look for prey.
They swim above the coastal shoaliness overgrown with bushes of eel grass. Long
narrow leaves wave in current, casting moving shadows on bottom. And among shadows
at the bottom one of penguins has casually noticed creatures move in silt. It
has turned aside and has swum along the edge of thickets. Its movements scare
away small long-bodied fishes having pattern of black spots. At the approach
of penguins fishes dig themselves in silt by the only fast movement, and bird
simply cannot notice them. Fish hides from view instantly, leaving after itself
only the little cloud of silt. It is rahirahi galaxia, one of the river inhabitants.
It also lives in lake, but penguins, preferring to hunt in thickness of water,
could simply did not notice them. But here, in the river, conditions are different
a little bit: many fishes prefer to hide in thickets, and it is necessary to
hunt in shallow water much more often, than earlier, and habitual tactics of
hunting are not applicable here. Birds should be content with casual prey.
The penguin swims through thickets of aquatic plants. It was one of elements
of hunting during the former life in lake, and also works here. But in lake
the whole group of drovers swam through the thickets, and here, when the penguin
acts alone, is very easy to avoid its chase: it is enough for fish to swim aside.
But for this purpose it should start to move, and then inevitably will give
out its presence. Some small fishes rush away, being scared by movements of
the penguin. The penguin does not feel movement of water so subtly, as it is
done by fishes by means of lateral line, and is compelled to be guided with
the help of sight, suitable for hunting in thickets only a little. Nevertheless,
it managed to see, how in thickets certain cross-striped body has flashed. The
penguin has precisely noticed a direction of movement, but has rushed at random
and has clicked its beak. It has felt something moving and slippery, struggling
in its beak, and has emerged, having seized jaws strongly. It managed to catch
small fish with prickly fins and contrast vertical black strips on the body.
The penguin has shaken up its prey, has dexterously turned it head to itself
and has swallowed with the only movement. It managed to catch young ‘ika-taikaha
– adult individuals of this species are enemies of penguins in lake. Probably,
in some years a ratio of forces between predator and prey would change to opposite
condition, but now this creature is a food. Having inhaled a portion of air,
penguin has dived and has continued hunting. It has noticed its female flashed
among thickets, and has joined her. Hunting goes on.
In searches of prey penguins have swum away to the coastal shoaliness. Here
among plant thickets there are sites of sandy bottom where in sunlight small
schools of little fishes and tadpoles and also false salamander larvae swarm.
It is a lot of prey there, but it is rather unfamiliar to hunters from the lake
got used to hunting in thickness of water and at the surface. But the most important
circumstance is that penguins are completely unfamiliar to larger inhabitants
of underwater thickets. Who are more numerous here – friends or enemies?
The penguin female surveys thickets of aquatic plants in depth. Suddenly she
has noticed somewhere from the edge of field of view certain fussy movement
in thickets. Female has instinctively frozen and began peering into thickets.
Having noticed its excitement, male searching for prey nearby has cautiously
swum up to her and began to look in the same direction. Birds have seen how
a certain creature of approximately their own size digs sandy bottom. Its movements
are fast and fussy. The creature quickly emerges to the surface of water to
inhale fresh air and also quickly dives to the bottom, continuing search of
food. It is not a penguin – its colouring in fact is one-colour: white spots
characteristic for penguins are not present in it. In addition at swimming this
creature paddles by hind legs, which long toes are connected by palama. It has
tail, but it is not peaked, as at the penguin, but wide and covered with naked
dark skin. It is not a bird at all, but small beast swimming near the bottom
in searches of snails and insect larvae.
When penguins have emerged to the surface, following them from the bottom this
creature has risen also. Having emerged, small beast has exhaled air squeaky
and has looked at penguins by small black eyes. It has cautiously moved nearer
to them and has cautiously smelt air. Not knowing what to expect from it, penguins
have swam away from this mammal and have cautiously looked at it. Small beast
has simply inhaled a new portion of air and has dived, having plopped on water
surface by its flat tail. And literally in the same second, but from another
side from birds, one more beast of the same kind has emerged.
The pair of penguins has got out on the riverbank. Here birds have found out
that river and forest are connected by the whole circuit of paths well appreciable
among marsh vegetation and wood litter. It is very similar to the colony of
penguins; therefore the pair of birds has walked on one path, feeling some anxiety.
Birds have quickly crossed riverbank and have stepped under tree shadow. There
are some footpaths leading to the forest, but all of them stretch in approximately
the same direction, therefore it is almost impossible to get off in a way. In
their way penguins have met one more animal similar to those ones which they
saw in the river. The animal hastened to the river, pattering its paws and holding
its wide tail stretched above the ground. Having seen penguins, it has chosen
another track and has run past them. Birds have hardly looked at it and have
continued the way on the track. One more mammal of the same kind with brownish
wool emerged from sickly grass of underbrush and has glanced at them curiously.
The track leads penguins towards the thickets of bush, to the place where many
years ago the big tree has fallen. After some tens steps birds have seen the
thing they wanted to see for a long time: in the ground under branches of one
of bushes the aperture blackens – it is an entrance to the hole. Having gone
deeper in bushes, penguins noticed some more holes in the ground. It is a good
sign from the point of view of birds: it seems to them, that they have got into
the colony of congeners. But this feeling stays incomplete: if there is no danger,
in colony of penguins loud voices are audible. Birds constantly quarrel because
of territory, communicate with each other and declare their presence to neighbours.
And here holes are present, but it is unusually silent. Bending down under bush
branches, penguins move farther in thickets and look around. They do not notice
anybody’s presence, but some tens eyes look at them attentively: owners of holes
hide, because they do not know what may be expected from these strange creatures.
Maybe, someone of them sees these strange flightless birds with white-and-brown
plumage for the first time. Tens noses smell air, trying to feel how do these
strangers smell. And their noses do not feel frightening or hostile smells.
Movements of these creatures also do not seem suspicious to inhabitants of holes,
and some animals have begun to get out of holes gradually to get acquainted
closer with strangers. From some holes small mammals with whiskered muzzles
have appeared. Penguins are the only birds appeared in this colony: not their
relatives, but waitorekes, local aquatic mammals, live here.
The colony of waitorekes is something similar to the colony of New Zealand mountain
penguins. These animals also love a society of relatives and live in forest,
but feed in water. Because of too plenty of concurrences in habit of life of
absolutely different animals, instincts of penguins have some kind of failure,
and birds do not feel like aliens in the colony of these rodents. Waitoreke
is a descendant of the rats introduced to New Zealand by people in historical
epoch. Waitoreke resembles externally a tiny beaver with whiskered muzzle, rich
fur and wide paddle-like tail. But in character of feeding this animal is more
similar to desman: waitorekes feed on aquatic invertebrates and small fish,
and if necessary they can attack together any large fish or false salamander
and bite it to death. Penguins are not similar to their habitual prey; therefore
waitorekes do not attack them. In turn, holes made by waitorekes cause obvious
interest in penguins. But the occurrence of penguins in colony has not done
without the certain misunderstanding: when birds have glanced into one hole,
towards them a whiskered muzzle of waitoreke appeared, and birds had to recede.
Near some next holes there was the same. At last, one hole appeared empty and
male courageously moved inside while female waited him near the entrance. A
bit later he has got out to the ground surface and has shaken off: in depth
the hole was crumbled, as it was empty for a long time. Nevertheless, initially
it will be bearable shelter. Not having met the discontent from the side of
waitorekes, male penguin has crept inside the hole again and soon therefrom
lumps of the ground had been thrown out. He started to expand a tunnel to be
possible to move inside the hole freely.
Similarity in way of life has turned the balance to the settling of penguins
in waitoreke colony. Besides the beasts preferring to hunt aquatic animals do
not represent any danger to penguins on land, and birds actually receive an
opportunity to nest, maybe, even in such unusual neighbourhood. And there is
just a proper time to nest – biological rhythms hurry birds, and in colony which
they have abandoned many females have already laid eggs and have started brooding.
Within several days the pair of penguins has examined all empty holes in waitoreke
colony, and finally has found suitable ones for them. They have chosen for life
one of holes at the edge of the colony, under branches of bush hiding an entrance
to it. The hole is abandoned for a long time and has strongly crumbled, but
it is dug out near the stone, and it is favourable for penguins, because it
corresponds to their hereditarily programmed representations about good dwelling.
Having found out this hole, male penguin at once has begun to dig it out – penguin
is somewhat larger than waitoreke is, and the hole seems a little bit narrow
to birds. He started to work very actively: from under bush the ground, which
has been thrown out from the hole, has fallen to various sides. Female, on the
contrary, spends a significant part of time searching for food. Many kinds of
fishes are found in the river, but not all of them she met in lake. Also in
river lack some kinds of fishes which were favourite prey of birds during the
life in lake. The supply of male with food depends completely from the female:
he almost does not interrupt the working, digging out hole and making it suitable
for nesting. Male hastens very much, therefore in brief minutes of rest the
female replaces him and herself adjusts the newly found dwelling. Male is very
tired, and the fish brought to him by female hardly covers his needs for energy.
But due to coordination of actions of both birds work goes very quickly. The
result of their works is a perfectly fortificated hole. The part of the main
gallery adjoins to the surface of stone and is bent under it; therefore the
hole is well protected from predators. At the entrance of the hole the small
wall of mellow and wet a little ground has grown, but paws of birds quickly
trample down and throw it about, therefore soon nothing reminds that somewhere
beside the digging of hole proceeds. And in two days of hard works penguins
came to a final step in arrangement of hole: they made the nesting chamber,
spacious enough to allow the adult bird to stand in it in full growth. Now they
can devote themselves to parental cares.
While some inhabitants of lake only prepare to become parents, at others parental
cares are already finished. Rangitahi frogs have made everything for their posterity
that they could for the brief adult life. Embryos in eggs are developed enough,
and now are seen through transparent jelly-like shell: creatures turned to lump
and slightly moving from time to time. They must wait only few days to hatch,
and then they will be given to the mercy of fate, and their survival will be
exclusively their own care. Until they will hatch, parents will protect them,
maybe, at the cost of their own lives. This price, however, is not so expensive:
adult individuals of rangitahi frog are strongly exhausted and will die in some
days. But, while they are alive, eggs will be under their protection.
In lake there are lots of lovers of frog eggs. More often these are fishes remarkable
in their omnivory and illegibility in meal. One of such fishes is ‘ika-kaihopu,
the predatory viviparous fish little bit similar to a pike because of the lengthened
snout and protruding eyes. Large female of ‘ika-kaihopu swims along the lake
shore, searching for clutches of eggs of rangitahi frogs. It also likes tadpoles
of this kind though it is rather difficult to search for them in the bottom
layers of water for a creature got used to hunt at the surface. But the clutch
of frog eggs represents fine nutritious food which is as tasty as tadpoles are,
unless of being slimy a little. Having reached shallow waters, where clutches
of rangitahi frogs develop, ‘ika-kaihopu swims to the nearest lump of eggs.
But parents do not leave the posterity in danger, therefore towards the fish
from egg lump two frogs creep. They are strongly exhausted, and joints of their
legs are clearly seen under flabby wrinkled skin. ‘Ika-kaihopu does not pay
any attention to them: slow movements of frogs do not guard it. Having slightly
opened its mouth, ‘ika-kaihopu has soaked up some eggs and has swallowed them.
And one of frogs has on the spot seized its head by paws. Its paws have clasped
long jaws of ‘ika-kaihopu, preventing fish to breathe normally. The fish began
making sharp movements by the whole body, trying to be exempted from the unexpected
and importunate opponent, but the frog has squeezed its paws using power that
remains, not giving it to open the mouth. The fish began to choke and has tried
to free, shaking the whole body. At last, it has made a high vertical jump and
plopped in water with loud splash. After impact against the water frog has unclenched
its paws and ‘ika-kaihopu has rushed away from its clutch. Having convinced
that the enemy has moved out, the frog has slowly creeped on aquatic plants,
returning to the posterity.
Two days has passed, and it seems like eternity for dying rangitahi frogs. Tadpoles
are developed completely under protection of slimy cocoon and egg shells. Now
they are completely ready to independent life and begin hatching. Egg shells
turned thinner so, that it is just enough to tadpole to straight its body, and
shell bursts. Tadpoles begin leaving the clutch one by one, dumping from themselves
egg shells and making the way through slimy mass in which the clutch was enclosed.
Rangitahi tadpoles have lengthened thin bodies, and tails make the significant
part of their length. Having got out from the rests of clutch, they at once
rush to lake bottom, searching for shelter among underwater plants and silt.
It sounds paradoxical, but the hatching of rangitahi tadpoles initiates a final
stage of a drama – the inevitable death of adult individuals. Frogs have physically
made for posterity everything they could, and now the chemicals appearing in
water at the hatching of tadpoles accelerate their death. Rangitahi frogs are
strongly exhausted after egg spawning and protection, and now are literally
decomposed alive. Full of life even some days ago, now they are covered with
necrotic spots and thin coating of parasitic fungi expanding on wounds and grazes.
There are only few hunters for them at this time – nutrients in their exhausted
bodies are almost absent.
Large neohanasaki moved to shallow gulf serving as the last haven for dying
rangitahi frogs. The large amphibian easily moves in water, wriggling with the
whole body and pushing from the bottom by toe and finger tips. Predator’s nostrils
feel a smell of death which is dissolved in water around. Neohanasaki has bad
eyesight; therefore it hardly can distinguish rangitahi frogs among plants.
Any of them are still alive, but the majority of rangitahi frogs is already
dead, and they do not drag attention of predator. Having felt weak movement
of water in front of itself, the large amphibian has waved tail, rushing forward,
and has simultaneously opened its jaws, having soaked up in mouth the half-dead
rangitahi frog appeared in front of its muzzle. Having taken it in mouth, neohanasaki
has opened jaws and has spat out such unalluring prey with disgust. Having emerged
to the surface, the predator has inhaled air and has dived again. It seems,
here it is nothing to do for it: the gulf became a communal grave for hundreds
of rangitahi frogs, and the smell of decomposition frightens off other animals.
Somewhere the death inevitably takes away its share, and somewhere life overcomes
barriers build on its way by circumstances. The pair of penguins expelled from
the society of relatives has settled down successfully in waitoreke colony.
Birds feel like in safety among these beasts which do not seem to be their food
competitors and do not encroach on their new dwelling. In colony there are some
empty holes and there is no competition for dwelling; therefore nobody prevents
penguins to live privately. And soon the event happened, that should happen,
though a little bit earlier if events would have developed differently a little:
the penguin female has laid the first egg. It lies in small pit in the bottom
of hole, without any litter, and from the moment of it’s appearing it represents
the subject of gentle care of female. In completed clutch it should be two or
three eggs; therefore female does not begin brooding yet. She feels rotundity
and weight of egg, touching it with feet and stomach, and these sensations start
the program of parental behaviour. Now she is ready to protect clutch and her
relation to world around began to change. Having caught rustle and steps outside,
she at once crept into the gallery and has uttered warning signal. But the familiar
male’s voice has responded her, and female has calmed down at once. There is
no danger now, therefore she has returned to the nest chamber, has passed her
male inside and has enabled him to see (though, to be more exact, only to feel
by touches of feet and body) the first egg in their family.
In two days the female has laid the second egg and after that began to brood
the clutch. Now she depends entirely from the male supplying her with food,
and appears on ground surface for very short time. After successful fishing
male feeds her and leaves again, but if he was unlucky in fishing and his catch
is not enough to feed the female, he simply replaces her on nest, having a rest
and enabling her to hunt herself. Such moments give female an opportunity to
take care of herself. She hobbles to water, stretching the legs which have become
numb from the immovability and dives with pleasure. Female starts to fish not
at once: for any time she simply enjoys an opportunity to swim quickly. Sometimes
she crosses the river up to the opposite bank and even gets out of water there,
and sometimes dives up to the bottom or swims at the surface of water, jumping
out like a dolphin. At such moments the fish caught casually or intentionally
represents, maybe, just an addition to the main feeling, to the pleasure of
freedom of movements. After limbering up the bird catches some fish, satisfying
her famine, and returns to the land. Here the parental behaviour prevails above
other again, and she hastens to the hole to replace her male.
The first week of brooding had passed so – some days similar to each other.
Female and male replaced each other on nest and moved by turns for the food;
their neighbours were not interested in life of penguins, and birds managed
to avoid the predators living in the river. Maybe, if this pair would nest in
the society of congeners, the habitual order of things would be kept further,
but in this case penguins nest in completely unusual conditions, and they will
come to get used to the future changes.
Approximately at the eighth day of brooding female penguin, having returned
to the hole after daily exercise, has noticed, that near the entrance of the
hole the pair of adult waitorekes stays. Beasts do not express any aggression,
but look into the hole and sniff by turns. And from the depth of nesting chamber
the muted hissing is heard – the male has also noticed their presence and is
trying to frighten them off from the dwelling. Having come nearer to the hole
entrance female penguin had also hissed, opening wide its red beak and expressing
by its posture the determination of protecting the house. The waitoreke pair
did not begin to get involved in the conflict – small mammals have simply run
off aside and have disappeared in the nearby bushes. Self-satisfied female has
got into the hole and has replaced on nest her male which has gone for fishing
immediately.
Next day, while brooding eggs, female has heard rustle again, but this time
already much more clearly than earlier. The bird has hissed and has opened beak,
but rustle has not stopped. It guarded the female; she has left from nest and
has moved to protection of precious clutch. Having bent down, she has walked
along the gallery and has seen near the entrance silhouettes of two waitorekes
are clearly visible against the sunlight penetrating inside from the entrance
of the hole. Beasts have hesitated for one second, but nevertheless have jumped
out from hole. Penguin female has not noticed that one wall of gallery was dug
slightly by these beasts, and at the floor of the gallery small hip of mellow
ground lays. Beasts have left, danger to the future posterity is not present
– therefore the bird has returned to the nest and has continued brooding. Monotonous
conditions are soothing, therefore her eyes closed soon, the head lowered and
the tip of beak has touched the ground. Female has dozed off and did not hear
any more that in gallery rustle was heard again: the pair of waitorekes has
returned. Silently and cautiously, trying not to disturb the owner of the hole,
waitorekes have continued their work in gallery – beasts gnaw the ground by
incisors, having biting off bush roots by the way, and throw it to the exit
from the hole by webby hind legs.
Penguin female had been woken by shrill squeak of waitoreke. It happened that
pair of these small beasts, not feeling any resistance from her side, has managed
to dig rather deep side gallery before the male penguin has returned. For him
the occurrence of these strange neighbours appeared a surprise, and he has taken
them as unwelcome guests. Male has loudly hissed and clicked beak, and then
has pinched wool of one beast. Its squeak was just a reason of female’s awakening,
and she crept through the gallery outside to expel the extraneous visitors from
hole. Waitoreke scared by female appeared literally squeezed between two birds
in the underground gallery. To avoid punishment, it has literally stopped at
nothing, having rushed under male penguin. Waitoreke has squeezed literally
under his stomach, having pressed male penguin against wall and ceiling of the
gallery, and having nearly squeezed out the fresh catch from his stomach. It
has got out of the hole quickly and has rushed to bushes where the second animal
of pair had already waited it. Despite of this incident, they are not going
to leave far and are obviously going to continue what they’d started.
The pair of waitorekes expresses direct interest not so much to penguins, but
mainly to their dwelling. The hole dug out by penguins seems very attractive
for the pair of waitorekes, and they would like to settle there also, despite
of resistance on the part of penguins. At first penguins related to this pair
of waitorekes aggressively enough, because these beasts came too close to their
nest. But gradually penguins have got used to the presence of waitorekes near
the entrance of the hole – these animals do not do anything bad and do not disturb
the brooding female. At the appearance of penguins waitorekes simply give them
way to the nest, avoiding the conflicts. This pair of rodents has acted rather
originally: they did not show claims for the whole hole occupied by penguins,
and have only attached at some depth the side entrance from the main gallery
and have engaged in their own building. Rodents dig a hole together, throwing
out the ground outside, and in the gallery leading to the penguin nest heaps
of the mellow ground accumulate. Waitorekes throw out a part of ground, and
penguins involuntarily help them while get out of the hole – birds push out
by breast in front of themselves some ground left by their new neighbours. But
this is an only inconvenience which waitoreke have caused them. When the hole
was ready, and the rests of the ground had been thrown out from it, penguins
have almost ceased to notice the presence of waitorekes. Only sometimes penguins
meet their neighbours at the entrance of the hole, but waitorekes let them pass,
preferring to solve small life problems without conflicts.
From time to time waitorekes try to squeeze into penguin nest chamber, but female
drives them away, hissing and clicking beak. She is still busy with brooding,
and the incubation proceeds successfully. While waitorekes add their tunnel
to the hole of penguins, almost two thirds of incubation term has passed. Less
than one week remained before the hatching of posterity at birds. Till the whole
time male regularly moves to fishing and supplies female with food, and also
replaces her on nest.
To reach the river, male penguin prefers to use convenient pathway worn by waitorekes
and animals do not pay attention to him when he waddles on the track. Some generations
of waitorekes laid this track, and now it is convenient for movement: the track
bends around obstacles and is smooth enough. But near the water the track runs
through rich thickets of coastal plants, therefore the penguin has to slide
on dirt on stomach, pushing by wings and legs. The penguin moves to feeding
not alone: some waitoreke beasts of various sizes and ages hasten to the river
side by side with him, mincing paws and having raised flat leathery tails above
the ground. When the penguin has reached the edge of thickets, water became
deep already; therefore the penguin has simply pushed by wings and paws against
the bottom and plants, and has swam. Following the bird, his shaggy companions
have almost silently dived into water.
Under water the penguin at once tries to leave thickets. It has already studied
places of feeding and has remembered some escape ways in a case of predator’s
attack. He also remembers the predators living in the river. Sometimes the penguin
had to see large neohanasaki swimming through underwater thickets, and once
only speed of swimming and responsiveness have saved him from an attack of one
of such giants (maybe even, from the same one which he saw – penguins do not
distinguish such predators “personally”, it is simply not necessary for them).
And more recently the sunlight flash on scales betrayed the presence of huge
‘ika-taikaha – a monstrous fish with wide and toothed mouth and eternally insatiable
famine. The penguin saw this fish only from apart, but it was a terrible reminder
on presence of dangerous animals in water. Therefore the penguin began to behave
much more cautiously, than at first.
While the penguin should leave from the riverbank for hunting, waitorekes do
not make distant sorties, preferring to search for food in coastal thickets.
Waitorekes dive not too deep, but it does not cause them any inconveniences.
They eat mainly invertebrates – snails and insect larvae. And such forage can
be found also in shallow water. Moreover, such animals usually do not differ
in great speed of movement; therefore for waitoreke the skill of diving for
a longer time has much greater value, than depth of diving.
Keeping in shallow water during the feeding, waitorekes avoid a set of troubles.
Usually river predators live in deep water, and only neohanasaki can threaten
these beasts when lies down on the bottom for a long time, mimicking the piece
of driftwood and waiting while careless waitoreke will swim up closer, not noticing
danger.
Male penguin has gone fishing once again. He managed to catch several small
fishes, and had a rest, swimming on the surface of water. The sky above him
is clean, and only voices of New Zealand false ravens and hoarse call of eagle
kea somewhere in the distance are heard. Having inhaled full lungs of air, the
penguin has dived. The school of small fishes has rushed in all directions when
he has swum along the thickets, searching for the pass leading to the land.
Waitorekes used it for many generations, and plants expand worse in this place
– they are in regular way pulled out or simply beat by paws and tails. Some
more minutes, and he will get out on land. The penguin has very good underwater
vision, and he notices how here and there above thickets air bubbles raise –
waitorekes are searching for food. The usual picture, which he has already got
used to observe, has a little bit dulled perception of the bird, therefore the
penguin not at once has noticed something else – also well familiar, but for
absolutely different reason.
Among plants the scaly back of large creature with tall fin has flashed, and
from movements of tail thickets waved as if in strong current, and on surface
some plants has emerged, being pulled out by tail of this creature. Cross-striped
colouring of sides does not leave any doubts: it is the adult ‘ika-taikaha.
The huge fish usually hunts in deep water, but, possibly, it had been involved
by waitorekes swimming among plants. Presence of the monster has forced the
penguin to rush to land. Forcing the way through thickets and dropping from
itself long leaves of the plants twisting wings and paws, the penguin has got
out on land somewhere aside from the track and has rushed away from water. His
panic was seen only by one waitoreke which had uttered loud whistle – warning
signal which penguins have learnt well, living near to waitorekes. Some animals,
having heard this signal, have got out of water and began looking around and
trying to find a reason of danger; but some animals being under water at this
time, have continued search of food. Animals did not see danger and did not
know where to look, and warning signal was single and was supported with nothing.
Therefore, not having felt a smell of predator and not having seen a silhouette
of predatory bird on trees, some waitorekes have made the great mistake: they
returned in water again. And only one of the beasts, appeared, probably, more
cautious than the others, has remained on land. And it had become an eyewitness
of awful scene.
Among thickets the scaly back has appeared, shining in sunlight. A certain creature
many times larger compared to waitoreke has made a rush, moving plant thickets
apart by head. Strong tail splashed water, and the creature turned around in
thickets, showing its cross-striped side. For one second the head of the underwater
giant appeared, large yellow eye has flashed in sunlight and struggling body
of waitoreke caught by fish has flashed. Some more impacts of tail followed,
and the monster have got out of thickets. Only its back fin has struck the surface
of water, and from river bed the cloud of silt has risen, marking the way of
fish. Everything had last for some seconds only, but waitorekes scared by appearing
of huge fish have not soon dared enter water. Adult ‘ika-taikaha fishes seldom
appear in shallow water thickets, but their juveniles frequently appear objects
of hunting from the side of waitorekes. Maybe, the beasts pursuing and devouring
small striped fishes in underwater thickets, do not guess, that these creatures
and the giant fear installing in them belong to the same kind, and, probably,
represent its progeny. But laws of a nature are those, that for the sake of
occurrence of one adult ‘ika-taikaha hundreds of its relatives should perish,
especially at early age.
Spring is most favorable time to bear the progeny, and almost at all water inhabitants
there comes breeding season in spring – at some ones it takes place earlier,
at others later. Light day becomes longer, and fresh water rich in oxygen entering
the lake from the mountain rivers stimulates changes in appearance and behaviour
of neohanasaki males. One male of this species has chosen for courtship games
a site of the lake shore overgrown with aquatic plants, near the place of confluence
of small wood stream. Neohanasaki does not mark borders of its territory with
specific smell or visual marks – it simply patrols borders of individual territory,
furiously driving away possible competitors. Within several days its appearance
gradually changes: the stomach turns bright yellow color with dark spots scattered
on it, and on skin plica bordering tail fin peaked jags appear. The outlines
of the male swimming near the surface of water in sunlight look very much recognizably
and represent thus the warning for others males which would decide to intrude
to its spawning area. Attracting the female, male is not hidden, as it behaves
during the hunting, but swims at the place covered by the sun, from time to
time plopping by tail on water surface. If on his site the female would come,
as a sign of submission she would keep in depth, and would appreciate the colouring
of male’s belly. And male will make everything for her to be impressed by his
magnificence and force. But frequently the magnificent display involves another
male instead of female, and his intentions appear rather aggressive.
Neohanasaki male swims in circles above thickets of pondweed with long stems.
From time to time he dives to bottom and with the help of flat head pulls out
any bush of plant, which seems to him as superfluous in his territory. Some
bunches of grass already float on the surface of water, and male moves them
away by head, because it prevents him to display himself. Occupied with cares
of the territory, it does not notice, how above the bottom the oblong brown
creature with flat head and short paws – its congener – is moving. Having driven
away the bush floating at the surface of water by muzzle, male has begun its
courtship display – it turned around and has swum along borders of its territory,
rising to the surface and churning the water with movements of its tail. He
has swum some meters when has felt, that his tail as if has got in a vice: the
competitor which has made a way secretively to his territory and hidden for
any time at the bottom has seized his tail from below and has hung down on it.
The moment for attack was chosen very successfully – impressive display of the
owner of territory was interrupted at the most improper moment. The owner has
made an effort, having dodged sharply, and his tail escaped from competitor’s
jaws. Now they appeared face to face on equal terms. Stranger male is almost
equal in size to the owner of territory, is obviously full of ambitions and
is not going to recede. Therefore the owner of territory has made the only true
decision – he has immediately attacked this stranger. He has seized skin on
one side of stranger male and at the same moment turned its body in parallel
to contender’s body, to avoid its bite. The attacked competitor has swum to
the surface of water, and the owner of territory has hung on its skin, seizing
its jaws. The skin of neohanasaki hangs from each side of its body in soft plicae;
therefore it hardly can be injured. But the might of jaws at neohanasaki is
great, and the bitten male all the same feels an acute pain. Trying to dump
from itself the furious owner of territory, it began rolling as if a spindle,
at the surface of water, plopping by tail. But the owner of territory does not
hurry up to unclench its jaws at all: the stranger has not taken to flight yet.
Continuing keeping the attacked contender, he scratches by short paws its skin
and beats the contender’s tail by its one. Fight proceeds about twenty minutes;
from time to time both amphibians lay motionless at the surface of water, twisting
their bodies around each other’s, but then fight proceeds with renewed vigour,
being accompanied by splashes and tail plops. At last, there comes an outcome:
stranger male gets away, having dived to the bottom. The owner of territory
pursues it only formally: blood and the killing of the contender are not the
purposes of the combat; therefore the flight of the contender is quite enough
for him.
Wounds at the winner male are minimal, and he continues the interrupted courtship
display, swimming forth and back above the thickets brightly covered by the
sun. At last, there comes the moment for the sake of which it works so hard:
near the border of his territory the female appears. She behaves peacefully,
displaying humility in all features of behaviour: she moves above the bottom,
stopping when male appears near her. She swims ahead closer and closer to the
center of male’s territory where he continues displaying himself. His stomach
is brightly coloured, and this colouring as if fascinates the female when male
swims right above her. Male touches the female by its stomach for some times,
swimming above her, and then cautiously bites her skin on back. Female endures
the pain, showing her humility, but male bites her skin only slightly and not
for long – it is not a combat, and he has no desire to banish the female.
Female has remained at the male’s territory for night, and in the morning right
after the sunrise courtship games of huge amphibians have begun. Neohanasakis
spawn far away from the coastal zone covered with decomposed corpses of rangitahi
frogs. They prefer spawning eggs in clean water among plants. At the sunrise
male began to show its force to the female: he began closing the way to her,
turning the side to her and shuddering with the whole body. When female turns
away from him, male again swims forward and stops, crossing her way by his tail.
At last, female has ceased avoiding him and has remained where she was. It became
the stimulus for the second part of courtship games. Male has emerged to the
surface of water and began to swim above the female in circles, loudly plopping
by tail on water and displaying its bright belly. Having dived, male has gathered
speed, rising to the surface, has jumped up, having put out from water almost
half of his body, and then has plopped in water sideways. His activity became
the stimulus for female which has also joined the race. Neohanasaki male and
female began swimming in circles together, touching each other by sides. After
several circles in thickness of water male has suddenly replaced a direction
of movement and has rushed to the bottom. He was lowered into the thickets of
aquatic plants, has cautiously crept among stalks, moving them apart by body,
and then has crept out and has emerged above plants. The nest for posterity
is ready. Having swam some times above the nest, neohanasaki male began pushing
female to it, hooking her under stomach by wide head. He has cautiously brought
female to thickets, has pushed her inside of thickets, has swam after her and
has clasped her body with short legs, seizing by fingers skin plicae on her
sides. Female has felt his touches and trembled by the whole body. She has strained
and has spawned among plants the large portion of the eggs capsuled in slime
cords like at frogs, their ancestors. Male has slipped to one side of female
and has immediately fertilized eggs, and then female has spawned one more portion.
While she spawned eggs, male did not let her off, but as soon as she has stopped
it, male began pushing her aside from the clutch, driving out from thickets.
When it seemed to him, that female leaves the nest insufficiently quickly, male
has strongly pushed her by side, and then has bitten tip of her tail, having
forced to retire. Female has played her role in breeding and now should move
away. And male’s parental duties have just begun.
Male has remained to guard the clutch which gradually absorbs water and turns
to the inflated slimy mass laying among stalks of pondweed bush chosen by parents.
At this time male eats of nothing, having devoted itself entirely to protection
of the future posterity. The fishes swimming nearby now become not prey, but
enemies: if neohanasaki male will lose vigilance, the clutch would be destroyed
by them less than in one hour. Therefore male has no right to leave from the
nest within several days to come, and even for longer time. However, having
slow metabolism characteristic for amphibians, neohanasaki male will not suffer
at all: the age of this individual is over forty years, and he protected the
progeny many times in succession.
Some days represent very short time for long-living neohanasaki, which age may
reach 90 years. In fact, the large individual, since the certain size, has no
enemies, and the animal can live as much time, as its organism is able to function,
fading away from natural old age. But for those ones which only prepare to get
in this world, such time may appear crucial. The small creature already from
the entering the world has numerous enemies; therefore the parental care is
a quite good help even for the future large predator. At the entering the world
its length is hardly more than length of finger of its own father. It is just
a real size of newly emerged neohanasaki tadpoles – they are small and helpless
creatures which can be eaten by almost any fish in this lake. The slimy mass
shrouding eggs is gradually dissolving, and the developed tadpoles get out of
it and hang on leaves and stalks in pondweed bush in which eggs had been spawned.
Near to this bush male is on duty. It has felt by smell that there is an important
event for which he waited during all last few days, and in reply to smell of
hatched tadpoles in his organism the important changes have started to proceed.
Tadpoles will spend the first day, hanging motionlessly on the plant and absorbing
stocks of yolk from resolving yolk sac, but then they become to move actively
and for them another food is required. And neohanasaki male has engaged in manufacture
of baby food in literal sense.
In the evening neohanasaki male had cautiously got into the bush of pondweed
and has felt easy touches to his skin. And in the next morning the whole brood
of tadpoles is already moved on his back and sides. And it has served as stimulus
for the next phase of parental behaviour at this huge amphibian. The skin on
back and sides of neohanasaki male began swell, and its top layer began to exfoliate,
being mixed with plentifully secreting slime. But while earlier slime served
only for greasing at movement in water and as protection against parasites and
infections, now when hundreds small mouths pinch skin, it has got temporarily
some nutritious properties. The male’s organism spends its own nutrients for
manufacturing of food for posterity, and this is a quite favourable adaptation
allowing lowering of the dependence of survival of neohanasaki tadpoles from
presence and abundance of food in the most difficult first days of their life.
Tadpoles attach to father’s skin by sucker-like mouths and scrape off the top
layer of skin. They do not leave from the male and surround him like bee swarm.
If there will be a necessity, male will protect them against almost any danger.
Spring is the time of occurrence of new life. Birds in forest are occupied with
brooding eggs or bringing up of nestlings, and in waitoreke colony some females
have already given birth. In life of the penguins settled in waitoreke colony
important changes also take place. A little more than one month has passed in
total from the moment when the pair of penguins had been expelled from the colony
of congeners. Maybe, the breeding instinct has forced this pair to settle in
waitoreke colony, and there comes a new stage of coexistence of two kinds of
animals simultaneously similar to and different from each other. At last, the
most important day in life of this pair has come. Even yesterday female had
heard how from eggs thin voices of the chicks ready to hatch sound. And now
she feels that changes come to the nearest minutes. Tiny beak began to punch
shell from within. After the first blows on shell little crack has appeared,
which becomes longer and longer with each new pecking. At last, from one egg
the triangular piece of shell breaks away, and in the aperture formed in twilight
of nest female sees a beak of the chick punching for itself the road to the
wide world. The second egg also rocks, and inside it the second chick tries
to peck through the shell. Female does not interfere with a natural course of
chicks hatching, and only rows up eggs under her sides by wings. She feels how
chicks became more active in heat and have started to hollow shell stronger.
At last, approximately in three hours after occurrence of the first opening
in shell, female has felt, as the egg-shell has broken in two parts, and something
has nestled against her side – something soft, warm and wet. Now it has healthy
and strong penguin chick, which cannot stand on legs yet and requires heat.
Female has cautiously taken from under her side broken egg shells and has split
them by impacts of beak, and then began to eat the pieces. Small stones in her
stomach will pound shell to powder. She feels how the second chick also tries
to get out from shell: the second egg moves under her side. Approximately in
half an hour its efforts also hade crowned with success, and female has felt
touches of both of her chicks.
When male has returned, he has felt at once, that something has changed in nest.
Even while moving in gallery he has heard absolutely new sound which female
utters – a silent guttural cackle. And the most important is that he has heard
also two squeaky voices answered her. And when female has risen from the ground
at his approach, male has seen even in darkness of nest against the background
of white plumage of female’s stomach two chicks having dark down.
Somewhere in gallery rustle was heard. Changes in home life have drawn attention
of neighbours of penguins – of waitoreke pair. One of beasts has cautiously
gone down to penguins, but it was met not with the hearty welcome – both adult
birds have hissed and clicked beaks. Fairly being afraid of the annoyed birds,
waitoreke has rushed up the gallery and has disappeared in their part of a common
hole.
The parental care is an important advantage which is received by neohanasaki
tadpoles compared to larvae of many other kinds of New Zealand amphibians. The
survival rate of posterity at this kind is very low – too much time passes up
to the sexual maturity, but even at this time full safety is not guaranteed
to young animal. And young tadpoles of the first days of life are very vulnerable
in general – not only almost any fish, but even the water beetle can eat them.
And father gives them both food and protection.
Protection never happens absolute: despite of presence of the adult neohanasaki
male, predators do not miss an opportunity to attack his posterity. The huge
amphibian is strong, but too sluggish, therefore having a certain measure of
dexterity it is possible to try to attack its posterity and to leave unpunished.
And one of lake predators tries to attack neohanasaki tadpoles – it is large
live-bearing fish ‘ika-kaihopu, a sort of “pike” of the New Zealand rivers.
It is able to mask dexterously and to attack quickly. And the help in masking
to it is rendered, strangely enough, by neohanasaki male. Preparing the place
for spawning, the amphibian has torn out from the bottom some bushes of pondweed,
and now one of them floats at a surface of the water, being carried by wind.
But this bush is floating not alone – near to it adult ‘ika-kaihopu slowly moves.
The wind drives pondweed bush at the some distance from neohanasaki male looking
after posterity, and fish would have an occasion to leave shelter for an attack.
But now it is coming nearer to the male under covering of the plant. Danger
for neohanasaki juveniles is quite real – this fish feeds on animals of just
their size and is capable to swallow a tadpole easily. But the wind gradually
drives drifting pondweed bush aside, and the fish is compelled to leave it.
It simply stays where it was when the plant floats away. ‘Ika-kaihopu moves
very cautiously, trying to not give out its presence. Its colouring has turned
much paler, and the body is almost completely motionless: one pectoral fin on
the side turned to opposite side from neohanasaki male with posterity works
only. The fish even breathes very cautiously, having slightly opened its mouth
and slightly moving with branchiate covers. It comes nearer to neohanasaki brood
very slowly, keeping its eyes on tadpoles scurrying carelessly above the male’s
back. The distance between predator and prey is gradually reduced.
Movement of tail of neohanasaki has lifted a cloud of sand and silt from the
bottom, having pulled out thus one more bush of aquatic plant, and frightened
tadpoles have rushed in all directions and have disappeared among plants. Neohanasaki
male has noticed the danger coming nearer right in proper time and has made
the true decision – to attack first. Maybe, he could not catch ‘ika-kaihopu
at the moment of its attack, but now the predator has made for his posterity
much more. When clubs of silt began to dissipate, and sand fallen down to the
bottom, the tadpoles scared by sharp movement of neohanasaki male, began to
come back to his safe back. Their father lies among pondweed thickets as before,
but now there is one essential difference: he holds convulsively moving fish
in its mouth. This time speed has lost to brute force, and life abandons a body
‘ika-kaihopu in clouds of its blood. Involved with a smell of blood of prey,
neohanasaki tadpoles swim right near the father’s jaws, forcing him to wait
with dinner swallowing. At last, male is bothered with it. He shakes his head,
frightening tadpoles away, and squeezes jaws. The bite smashes head of predatory
fish, and under water weak crash is heard. Having slightly opened jaws, neohanasaki
male turns prey head to him and swallows it entirely.
The predator is defeated, and this time the posterity is saved. In some days
the male’s parental instinct will fade and posterity will be given to itself.
But now, while male protects posterity, any animal in which he would see any
threat for tadpoles will not come nearer to them. On the other hand, if to find
the correct approach, it is possible not to be afraid even of such monster.
Neohanasaki male does not see anything suspicious in rotten leaflet with strongly
destroyed edges floating closer to him. He has bad sight, and he simply does
not distinguish this leaflet from some more ones floating on the surface of
water. The lake is surrounded with forests, and there are lots of fallen leaves
in water. But the giant does not suspect at all, that it has become a victim
of the dexterous deceit. The rotten leaflet to which he has not paid any attention,
is actually not floating at will of current, but is swimming actively and its
final aim is back or side of this neohanasaki. Tadpoles also do not differ neither
in visual acuity, nor in ingenuity; therefore they are not noticing that the
stranger, even harmless, is swimming to them. The edges of leaf begun to rot
represent only the illusion, a pattern of dark brown spots on bright green background
of body of small fish with deep body strongly compressed from sides. It is a
tiny viviparous fish ‘ika-‘iti, or leaf-mimic live-bearer. Masking is its only
protection against enemies, and at this kind it is brought to perfection. Transparent
fins do not break the accuracy of leaf imitation, allowing fish to move cautiously
to smaller prey, and if necessary to imitate plausibly the rotten leaf of tree.
Neohanasaki tadpoles are too large for it to be its prey, and ‘ika-‘iti is not
going to attack them. It is interested with food of other kind: of skin secretions
of neohanasaki male. ‘Ika-‘iti is an omnivorous fish, and it willingly uses
a gratuitous entertainment in case of opportunity. The thing impossible to make
to large predator is easily succeeded by small peaceful fish: it cautiously
swims up to the huge amphibian lying among plants, and moves into the school
of neohanasaki tadpoles. Tadpoles creep on skin of their father, scratching
out nutritious skin secretions, and cautious ‘ika-‘iti shares their meal. Its
mouth is capable to extend like a tube: the distant relative of this kind is
predatory ‘ika-kaihopu. But, using its tiny size and masking, makes things inaccessible
for ‘ika-kaihopu: having “standing on head”, it pinches accurately flakes of
nutritious slime from skin of the amphibian. The predator does not notice a
stranger among its own posterity and cannot distinguish its own progeny from
strangers. And if he would manage to distinguish them, how would he separate
the own progeny from strangers? For him ‘ika-‘iti feasting among tadpoles is
only a small leaf. It is good that ‘ika-‘iti does not represent any direct danger
to neohanasaki tadpoles. And they will be protected by father from the other
troubles.
Not all tadpoles have the same luck with parental care. Rangitahi tadpoles initially
lack of parental care – features of biology of this species are those. The only
things that parents could make for them are to protect, as far as possible,
developing eggs and… to fertilize shoalinesses with their own bodies. And they
have fertilized water with organic substances so strongly, that in some gulfs
it even became yellowish and muddy. Decomposed bodies of rangitahi frogs have
caused plentiful development of microorganisms, and after them also of microscopic
crustaceans and worms turning to food for larger inhabitants of lake including
rangitahi tadpoles. Tiny, almost threadlike tadpoles hide in great numbers among
plants. They scrape stalks and leaves of underwater plants, and also bones of,
maybe, their own parents. Sometimes tadpoles rush to thickness of water, seize
infusorians, crustaceans or worms floating by, and then hide in shelters again.
They are numerous, but too vulnerable for predators – many inhabitants of lake
would like to diversify their diet with these soft and defenseless creatures.
Therefore their escape is in being careful. But there are predators which succeed
to lull the vigilance of rangitahi tadpoles.
‘Ika-‘iti is an expert in masking. One fish of this kind has hidden under thickets
of floating Azolla fern which is driven by the wind on the surface of water.
Having masked, is swimming above shoaliness which has served both as nuptial
bed and a tomb for rangitahi frogs during some weeks passed. Among plants numerous
thin translucent tadpoles swim, being hardly distinct in thickness of water.
They quickly hide, when near them small fishes or water beetles swim by. Care
saved their lives more than once, and still will save many more times. But all
the same some of them will lose the life to any predator which would appear
more successful, quicker, more cautious, or… more imperceptible. Azolla thickets
involve tadpoles. This plant gives shadow which helps them to hide from enemies,
and on the bottom surface of plants it is possible to find many edible microscopic
animals. Tadpoles at lightning speed cross the distance of some centimeters
between thickets of plants at the bottom and floating islet of Azolla fern.
They at once attach by mouths to roots of fern and begin scraping the cover
of microscopic animals, not paying attention to the thing looking simply like
the leaf begun to rot from sides. They obviously do not notice a danger which
is quite real. ‘Ika-‘iti stays motionless among roots of plant hanging down
in water, slightly moving its fins. Its masking is perfect enough to deceive
even sharp-sighted predators. And rangitahi tadpoles with their bad sight are
easy to deceit.
One small tadpole has swum up to the head of the hidden fish. ‘Ika-‘iti lays
in pose unnatural for fish, on one side, head turned downwards. The tadpole
has cautiously touched its skin by lips and gathered from it the stuck particles
of vegetative dust. ‘Ika-‘iti is motionless; only its eye slightly turns, watching
the tadpole. When nothing suspecting rangitahi tadpole appeared near to its
head, ‘ika-‘iti has opened its mouth, having extended its like a tube, and has
soaked it up in single fast movement. Other tadpoles scurrying among Azolla
roots have not noticed disappearance of their relative, and have continued so
careless feeding… disappearing imperceptibly in ‘ika-‘iti’s mouth. The fish
has had time to be sated before tadpoles have felt the threat emanating from
it. And when it was moved carelessly, the scared tadpoles have rushed downwards
and have disappeared in silt and among plants.
But protection which plants and silt give is not also absolute. The rivers and
lakes of archipelago are inhabited by various species of fishes adapted to different
ways of food getting. Therefore, having disappeared from ‘ika-‘iti, tadpoles
of rangitahi frog appear vulnerable for another inhabitant of lake. Small fish
with narrow and lengthened body comes up from shelter representing small hole
which walls are stuck by slime. It is not able to swim quickly, but slides and
wriggles among plants dexterously. It has small eyes, and in sides of its mouth
the pair of short wattles grows. It keeps very cautiously, disappearing in silt
and vegetative dust at the slightest signs of danger. It is rahirahi galaxia,
one of few truly New Zealand kinds of fishes. The significant part of rahirahi
galaxia population inhabits the rivers, and in lake this species lives mainly
near the shore, avoiding its deep-water areas.
Due to the sensitive cells concentrated in short wattles rahirahi galaxia feels
the presence of the tadpoles dug in silt even if it does not see them directly.
But rangitahi tadpoles are so numerous, that to a fish is enough to stick its
head into silt in any casual place to find out a tadpole. Rahirahi galaxia swims
above the bottom, shaking head in sides, and its wattles at this time strike
on the top layer of silt. Suddenly fish rushes violently headfirst into the
silt in a little cloud of silt. Its long spotty body wriggles in silt and one
second later its head flashes; the struggling tail of rangitahi tadpole sticks
out from its mouth. Galaxia quickly swallows it and then continues search for
prey.
Some tadpoles did not feel any parental care from the moment of coming into
the world, and others will lose it very soon and will be compelled to struggle
for the existence alone. Parental cares of neohanasaki male come to an end.
For some times he drove away from the posterity certain predatory fishes, and
once even too curious penguin. His tadpoles have appreciably grown up, feeding
on plentiful food the male had gave them during all these days, and their number
has almost not changed, but for the death of several individuals weak from birth
and casual victims of small predators like water beetles from which the male
cannot protect the posterity. The giant lies among plants, resembling externally
a mossy log. His skin has turned pale, and in some places its top layer exfoliates
like rags from under which the new smooth skin is visible. Male lies motionlessly,
from time to time scratching body by short paws. One hind leg has seized skin
plica on one side and has pulled it. The peeled layer of epidermis has easily
slipped off, exposing bright brown skin. Neohanasaki male has bad vision now
– the skin on its head also flakes off and exfoliates, closing its naturally
small eyes. Having jerked, male has scared away tadpoles which still surround
him looking like a bee swarm. The skin on his jaws exfoliated, and he has waggled
the forward part of its body, trying to free from rags of skin. At last male
has simply crept forward through rich thickets of pondweed. Tatters of skin
were hooked against the plant, and the large amphibian has continued movement,
feeling as old epidermis peels off from him as an entire layer. Tadpoles follow
the father as they always did in their life so short yet, but now he does not
pay attention to them anymore. Male jerks some more time, and then waves its
tail and swims forward. His old skin has remained among thickets, and after
the moulting his parental cares come to an end. Now he can live his own life
till the next spring. Moving its tail, neohanasaki male has disappeared in greenish
depth of lake, and only among pondweed thickets his old skin sways as white
translucent tatter. As if trying to take everything that father can give them,
tadpoles scrape his peeled off skin, gathering the rests of “baby food” produced
by the organism of male protected them. When this food will be over, they must
come to live independently, relying only to their own abilities.
In colony of New Zealand mountain penguins located in forest at the lake shore
numerous chicks had hatched: almost at each pair of adults two chicks have appeared.
At some birds one of chicks has already had time to dies, and they bring up
the only offspring. However, if the pair of birds not amicable or has insufficient
experience in chick rearing, the death of one chick lets them bringing up the
second one successfully. But the experienced pair of birds easily copes with
bringing up of two chicks at once. But now it is too early to talk about success
or failure of any pair in bringing up the posterity – their chicks have just
got out of holes. And now, maybe, only absolutely deaf predator would not find
a colony of penguins. Demanding their portion of food, chicks cry loudly. Having
seen their parent coming back from fishing, they run towards it and inevitably
get on another’s territory, causing displeasure of its owners. Borders of territories
at this time are broken at least every some minutes, and to calls of chicks
craving for food voices of displeased neighbours, banishing strangers from their
territory, join also. Some chicks living at the edge of the colony and closer
to the paths leading to the lake prefer to wait for parents and other colony
members right at the path, under fronds of ferns grown up appreciably from the
beginning of spring. Noticing any congener hurrying up to get home after successful
fishing, chicks one by one or in pairs rush to it, scrounging food actively.
Sometimes the effect of suddenness works: the penguin belches the caught fish
before it understands that not its own chicks are fed now. Frequently chicks
get pokes and pecks, but sometimes they succeed to profit by gratuitous food.
In addition it is possible to have a sleep in shadow under ferns in relative
rest from other members of colony.
The location of penguin colony is well familiar to ruacapangi – large predatory
bird controlling this part of forest. In second half of spring eagle kea, the
assistant and the informer of this feathery predator, is busy with its own private
life, and ruacapangi hunts alone. However, even without the assistant ruacapangi
hunts successfully enough. In spring in forest it is possible to find lots of
young animals of various species, and ruacapangi does not miss an opportunity
to attack the inexperienced animals not capable to repulse.
Wet rotten foliage, soft moss and sappy shoots of grass muffle steps of ruacapangi.
The bird has heard voices of penguins from apart and has decided to push its
luck. Ruacapangi creeps to penguin colony cautiously, bending down and standing
motionless for a long time. It is able to be patient and chooses the proper
moment for an attack. Ruacapangi steps very cautiously, trying to not make superfluous
noise: bird has a wide experience of hunting, and it is able to prey even cautious
animals. Low-sized penguins do not notice ruacapangi, and it allows this bird
to come close enough to their colony. And when one of birds has noticed this
predator nevertheless, it was too late.
Ruacapangi has rushed to penguin colony and in some strides appeared almost
in its center. Warning signal was late hopelessly, and not all penguins managed
to hide in their holes. Some of them, saving their lives, have rushed to another’s
holes, but at this time they have not met repulse from the part of owners which
also have preferred to squeeze deeper and to keep silence, hoping, that the
predator will pass by. The worst of all was the situation of several chicks
lived at the edge of the colony: they simply had not time to reach holes, and
now are compelled to hide from bird’s sight among ferns surrounding them. And
it is rather risky occupation – to deceive ruacapangi, it is necessary to have
considerable self-restrain. Not any forest inhabitant can keep an absolute immovability
and hold its breath when this ruthless predator, having also acute hearing,
passes by. Penguin chicks are simply not able to hide from the enemy in forest;
therefore they are threatened with real danger.
Ruacapangi walks in colony of penguins, listening and looking in sides. Birds
were squeezed deep in holes; therefore ruacapangi hardly can get them, even
if it will push head into the hole. And this bird also has not enough forces
to dig out a hole – stones near to which penguins arrange entrances to the holes
prevent this predator to do it. Nevertheless, the bird does not hurry up to
leave a colony of penguins – it walks across it, listening carefully. And then
it walks along the edge of a colony turned to lake, where tracks, on which birds
return home, come to an end.
Penguin chicks look in horror at huge bird wandering across the colony. At the
instinctive level they understand, that it is a dangerous creature: in general,
every animal larger, than the penguin, may represent any danger for it. And
this bird expresses obvious interest to holes of penguins, and its appearing
had been connected to an alarm signal. Chicks have remembered this lesson, but
they do not know the most important thing – how to avoid danger which this monster
represents. The best way to protect against ruacapangi would be a complete immovability:
having nestled against the fern or even having slightly dug in wood litter,
penguin chick would be imperceptible for this bird. The black down of chicks
would help them literally to dissolve among forest shadows. But they still have
not enough experience to play such games with fatally dangerous predator.
One chick has not sustained a tension: when ruacapangi has gone along the edge
of colony, it has rushed ahead, hoping to escape from the predator in forest.
Predator’s reaction had been instant: ruacapangi has turned around, has made
long jump, has picked up an escaping chick, has thrown it up, has caught and
has swallowed entirely. But this tragic event has helped several another penguin
chicks to escape: when ruacapangi has run for that chick, they managed to reach
the nearest holes and to hide there. Of course, these were another’s holes,
but in the face of real danger, all members of colony are equal and it frequently
saves their lives in the dangerous world these islands turned to after the ending
of human epoch.
Waitoreke colony, in which penguins left from a colony of relatives have settled,
is also not a quiet place. Waitoreke themselves behave peacefully enough relatively
to each other and between them the conflicts connected to quarrels for territory
or food flash much less often. But in waitoreke colony there are specific problems.
These small mammals have a lot of enemies from which it is necessary to defend
themselves.
Predators observe of waitoreke colony from the tree. The pair of New Zealand
false ravens is going to hunt these animals. Birds, usually noisy and appreciable,
behave silently and cautiously, trying to hide in branches. This tactics paid
back for many times: usually waitorekes trust smells and sounds, and their sight
is insufficiently keen to distinguish a raven among branches, and additionally
at the great height. But now there are not only waitorekes in colony and the
pair of ravens did not consider this important circumstance. While the penguin
female is fishing at the river, male keeps in touch with the situation. His
attention was not escaped by small black down feather whirling in air. Having
raised head upwards, the penguin has seen how among branches the large black
bird cautiously moves, and on next branch one more bird perches. The shape of
these birds is very recognizable, and the penguin, having uttered a short alarm
signal, has rushed to the hole. He has pushed two curious chicks deeper inside
the nest chamber, and turned around head to the entrance, ready to give fight
to any enemy which would want to enter the hole.
The alarm of the penguin was noticed by his neighbours in proper time. Having
seen how the penguin has absolutely unexpectedly rushed to the hole, one waitoreke
beast has uttered warning whistle and has disappeared in hole. Some more animals
repeated its signal, and from the river, as if an echo, congeners have responded.
The waitoreke colony, full of life even few seconds ago, as if became deserted.
Beasts, not having understood at all, from where the danger comes, have warned
about it their relatives and have hidden.
New Zealand false ravens have flied down from tree to waitoreke colony. They
had been noticed, therefore now birds have no sense to hide. Vigilance of the
penguin has complicated their hunting, but has not made it completely impossible:
ravens have in reserve many ways of food getting. But at first birds want to
look round and to define what tactics can be used. Two ravens wander on the
ground, look around and poke beaks into holes. Some holes are empty, and other
ones are too deep to make possible for them to discern something inside. It
does not stop ravens: they compensate absence of any opportunities with the
ability of using of objects of world around for their purposes. Birds of this
kind have skills of use of simple tools – various objects found in nature. The
experience of tool using is transferring from parents to posterity, and individual
skills of tool use are improved within the all further life. New Zealand false
raven female has looked round, and then has walked to the edge of waitoreke
colony. She has found out in bush a dry stick fallen from the tree growing beside.
The bird has pulled out this stick from bush, having broken thus a twig on its
side. It is easy for making – stick is dry and fragile. Moving back, bird had
dragged the stick to the place between holes free from bushes. Having taken
it for thicker end, raven female has clumsily approached to one hole and has
put it into the hole by sharp movement. The answer was a squeak from depths
of hole – this waitoreke was at home. Raven female has put stick even deeper,
and squeak has repeated. The bird has dragged stick from the hole and has glanced
inside with one eye again. Having discerned of nothing, she has used the stick
again, but this time the silence was an answer to her actions. Raven female
has moved stick in hole, and then has put it inside of hole so deep, that her
head and neck appeared in hole up to shoulders level. But it appeared ineffectual.
Waitorekes also have some tricks in reserve. If the hole would have only one
exit, it would become a trap for its owner; therefore some neighbouring holes
of waitorekes are necessarily connected by tunnels. When raven female has taken
stick out from the hole, she has made a mistake: she has simply allowed the
beast to escape in the next hole. While the pair of ravens walks in waitoreke
colony, beasts prefer to stay in holes. They only cautiously observe of birds,
having put out from holes only noses, and instantly hide when ravens only take
a look in their side. The penguin, staying in the hole, also does not hurry
up to get out outside. Maybe, if these ravens would have decided to engage in
robbery in colony of penguins instead of waitorekes, the population of the colony
would render them worthy repulse. But local inhabitants obviously prefer the
different tactics of protection; therefore the penguin left alone to protection
of the dwelling, would look rather strange and would subject itself to real
danger, not having any support from among waitorekes. Therefore he also has
preferred to hide in hole while enemies wander in the colony.
Penguin chicks hatched in waitoreke colony gradually grow up. Waitorekes perceive
them as members of the colony, therefore penguin chicks are in safety though
waitorekes frequently rob, eating chicks of ducks and other waterfowl. Penguin
chicks are already bored to stay in dark hole, and they wish to get acquainted
of the world around. Curiosity takes top above care, and every next day chicks
move closer to an exit from the hole. Light and the sounds getting into the
gallery from an entrance draw their attention.
The first members of colony which penguin chicks have got acquainted closer
are their neighbours – breeding pair of waitoreke attached their hole to the
hole of penguins. When penguin chicks impelled by curiosity began creeping up
the gallery, they had found on their way the entrance to waitoreke hole. One
of penguin chicks has cautiously glanced into the hole and has immediately recoiled
back. From the hole the whiskered muzzle of waitoreke female appeared. Chicks
had been frightened a lot – they had never seen these animals so close before.
But waitoreke female has only sniffed at them, showing its large incisors with
yellowish enamel. Chicks smell the same as adult penguins to which smell waitorekes
have got used. Therefore after the short acquaintance with penguin chicks waitoreke
female has moved back, turned around and disappeared in depth of its hole. And
there, above, literally in ten penguin steps, the huge world is stretched, attracting
by its novelty. Penguin chicks make some more steps towards to this new world,
but… The acquaintance of it is delayed for any time: waitoreke male has returned
home. It was also interested with two creatures that seem to be covered with
black wool, which stand in gallery right at its way. Waitoreke male has taken
a view, and then has smelt them. Its caution is evident: they are the first
chicks of New Zealand mountain penguin which it happens to see in the life and
so closely in addition. But the familiar smell coming from them has calmed it
and has removed the mistrust. Having looked at chicks once again, waitoreke
male has made some steps towards them. Chicks have delayed, and it had to stick
nearest of them with head in order to force it to recede back. Pushing them
step by step, waitoreke male has reached an entrance to its hole and has disappeared
there. And chicks have cautiously hobbled to meet the world around.
Not having got out from the hole yet, chicks have already felt a diversity of
the world in which they should live. Sun beams penetrate tree crones, the foliage
rustles in wind, and somewhere in height strange and unfamiliar sounds – calls
of local birds – are heard. Branches of bush under which the hole is dug out,
partly close their field of view, but even the small part of things seen by
chicks from the hole impressed them a lot. They cautiously move to the exit,
looking around and listening to sounds of world around. Some more steps – and
chicks already stand at the edge of the hole. They extend necks and take a look
from the hole for the first time. The world around strongly differs from the
nest chamber which seems now so close to them. Above their heads branches of
bush stretch, hiding an entrance to the hole from curious sights of some forest
inhabitants. Chicks inhale the fresh air strongly differing from air in their
hole smelling as ammonia. Their eyes gradually get used to the variety of colours
of world around, but chicks still behave very cautiously and do not dare to
depart even to a single step from the hole.
Behind backs of chicks footfall of small paws was heard followed by dissatisfied
puffing. Waitoreke pair has left their hole and has decided to go to the river
to have a meal. And penguin chicks standing at an entrance of the hole obviously
prevent them to pass. Waitoreke female wants to get out from the hole the first.
She cautiously pushes penguin chicks by head, but they do not hurry up to let
her pass. Not seeing what is happening, waitoreke male has simply bitten female’s
hip in order to stimulate her to move quicker, and the female, having screamed,
has pushed penguin chicks away and has got outside. After her male has got out
from the hole and both beasts have run on the track leading to the river. And
chicks have quickly returned to the entrance of hole. Now the world around seems
to them too obscure and frightening. But one sound has forced them to quicken:
from the side of track the voice of their mother coming back with full stomach
of small fine fish and tadpoles was heard. Chicks began to look around and to
cry loudly, calling the mother to them. In reply to their calls the voice of
mother is heard all closer and closer. At last, chicks have seen how mother
squeezes to them under branches of bush and have rushed to her together, loudly
asking for food.
Due to plentiful feed penguin chicks grow quickly. In waitoreke colony they
do not have competitors, because penguins and waitorekes eat different animals
and hunt in different places of the river. Besides young waitorekes have no
habit to take away each other’s food, therefore nobody of them encroaches on
food which brought to chicks by parents. Only occasionally young waitorekes
watch how penguin chicks get food from mouths of their parents, but do not make
attempts to take it away as it would happen by all means in the colony of penguins.
Gradually young penguins turn brave and begin to walk off from the hole, being
interested in life of waitorekes. They do not see relatives around of themselves,
therefore prefer to keep side by side and frequently even nestle against each
other by sides. Now their age is about one month, and they have considerably
grown in comparison with the moment when they just hatched. Life of penguin
chicks without coevals would be boring, but young waitorekes add some diversity
in it. Waitoreke cubs constantly scurry beside, busy with games and learning
the world around. They caper, having raised flattened tails, run one after another
or struggle, scratching and slightly biting the contender. Sometimes in struggle
some cubs take part at once; they form a live fluffy heap, pushing and biting
their game partners. And then from under heap thin squeak of the cub appeared
at the very bottom and pressed down by the others is heard. Chicks do not get
involved in waitoreke cub games, but sometimes they should take part in them
without their will. Waitoreke cubs like to creep behind very much silently,
then to attack and to seize penguin chick’s tail, causing it to shrill loudly.
Nothing threatens to chicks – waitoreke cubs like to play so with each other.
If near them any adult penguin appears, waitoreke cub prefers not to continue
this game – some most courageous ones of them have already received from birds
strong impacts of beaks. But if parents are not present nearby, penguin chicks
are compelled to protect themselves by their own means.
One young waitoreke has decided to enter the game with penguin chicks. Two penguin
chicks stand on the ground, being heated in rays of sunlight penetrating through
forest canopy. Their dark down allows them to get warm quickly, and they sunbath
with pleasure. Warm and rest incline to dream, and eyes of chicks begin to close
gradually. One of chicks still tries to struggle with dream, moving head up
and forcing to open eyes, and the second one has already fallen asleep, having
placed its beak in down on chest. At this moment young waitoreke has crept to
them from behind and has seized tail of one penguin chick. Having squeaked with
pain, penguin chick has rushed forward and has fallen down the ground, and young
waitoreke has continued to pull and to slabber down on its tail. And then the
second penguin chick has made an unexpected step: it has seized young waitoreke’s
tail and has pulled it with effort to itself. Its beak has strongly seized tail
of small waitoreke, and hind legs of tiny beast have come off the ground and
have jerked in air: its forepaws keep for the ground, and teeth still bite a
tail of another penguin chick. Having seized the moment, seized penguin chick
has torn its tail out from teeth of waitoreke and has run off to some steps.
And the second penguin chick has continued to keep young waitoreke by the tail.
Feeling pain, seized beast has begun to squeak desperately, and others waitoreke
cubs, having heard its voice, have stopped the games and have looked in its
side. Seized cub has pulled out its tail from the beak of penguin chick with
some efforts and has rushed to the hole, cheeping resentfully. The others cubs
have gradually returned to their games and penguin chick have found again the
place on the ground covered by sunlight and began to bask, waiting for parents
with food. Now their life became little bit quieter: they have found a way to
repulse too importunate neighbours, and they, in turn, became less importunate
relatively to their feathery neighbours.
Waitorekes are not the unique mammals inhabiting forest, and are far from being
the largest ones there. The waitoreke colony should frequently face with larger
inhabitants of New Zealand forests. More often these are peaceful herbivorous
beasts, but even from them it is possible for small beasts to wait for troubles,
at least casual.
In spring at ultradama does fawns are born. Almost right after birth they are
capable to follow mother, but all the same are vulnerable for such predators,
as marsupial pardus and ruacapangi. Therefore does with fawns prefer to gather
in small herd to protect them in common. Due to large size it succeeds for them
easily to drive away small predators or to hold them at the safe distance from
posterity.
In the forest a group of ultradamas moves slowly – it includes five adult does
with fawns born approximately one month ago. The wool both at does and at fawns
is covered with white spots on reddish-brown background. When different does
and their posterity meet each other, individual distinctions in colour of wool
of these animals become appreciable: at one doe wool is light brown with yellowish
shade, and such color was inherited by both of her fawns. And at another doe,
on the contrary, background colouring of wool has darker shade. Ultradama doe
usually gives birth to two fawns, and only one young doe in this group takes
care to the only fawn – it’s first-born one. The next year, having got stronger,
it can give birth to twins, as usually takes place at this species.
Ultradama doe behave thoughtlessly and carelessly, arranging games and chasing
each other among ferns and sickly bushes in underbrush. Adult does behave much
more cautiously: there is an important reason to do so. Away from herd, observing
a safe distance, ruacapangi follows – an adult bird, male in the prime of life.
It has recently left its female and chicks of last year’s brood, and now, being
not burdened with cares of posterity, presumes to itself to “shepherd” the herd
of herbivorous beasts, waiting for an opportunity for an attack. Ultradama does
smell it and sometimes see its brown plumage flashing among bushes. Therefore
adult ultradama does try to keep between this bird and fawns to repulse in proper
time a probable attack. Ruacapangi male is not going to attack them – of course,
ultradama fawn has good taste, but now it cannot be preyed without meeting its
mother ready to protect it. And crushing blows of hooves of its front legs can
kill adult ruacapangi on the spot. The predatory bird is involved with another
circumstance: at their movement in forest large animals disturb and frighten
small animals which usually hide well, especially if they notice a predator.
And such prey draws attention of ruacapangi.
Ultradamas go down to the river, and their way passes directly across waitoreke
colony. Massive animals do not pay attention to smaller forest inhabitants and
their occurrence in waitoreke colony is comparable in destructive power to act
of nature. Some waitoreke holes appear caved in by hooves of these deer. The
only thing that waitorekes can make is to run away from under hooves of large
beasts, uttering loud alarm signals. Penguin hicks had never seen yet such large
beasts so close, and they were very much frightened by ultradamas in spite of
the fact that these animals are herbivores. They had time to disappear in hole
and are only listening as hard blows of hooves of these animals sound through
the ground. Many waitorekes also have preferred to hide in holes, but several
animals in a colony simply have no place to hide in – their holes are destroyed,
and they will need to dig out an entrance and to throw out from holes the crumbled
ground.
Ultradamas had stopped for a while in waitoreke colony, feeding on bushes. Fawns
half-heartedly taste food of adult animals, and then begin to play, chasing
one another in the thickets of ferns surrounding the colony. But things, which
seem to only a game to them, bring lots of inconveniences to inhabitants of
the colony. Waitorekes are compelled to seek safety in flight from under legs
of these unbidden visitors.
Occurrence of ruacapangi was fast and unexpected. The bird has rushed directly
to playing ultradama fawns. They did not interest ruacapangi male by themselves,
but their game has frightened away several young waitorekes noticed by feathery
predator. Scared by the appearing of ruacapangi, ultradama fawns have rushed
away with plaintive low, and their voices have forced adult does to take alarm.
Large ultradama doe has rushed across the way to ruacapangi, forcing the bird
to do sharp turn and jump. Ruacapangi managed to avoid a meeting with ultradama
doe, but it has reared up and has made a leap in its side, ready if necessary
to bring down killing hooves of front legs on it. Ruacapangi male had to recede
– hit of hooves of ultradama would easily break its backbone or flatten out
its skull. And this female is followed two more ultradamas also attacking ruacapangi.
Forces are obviously unequal; therefore ruacapangi male has preferred to disappear
in bush.
While giants are at war, small creatures are compelled to seek safety in flight.
The majority of waitorekes managed to hide in holes, and some individuals are
compelled to hide among ferns and under roots of trees. One waitoreke has rushed
to the bush where the hole of penguins is located. Having seen an entrance of
penguin holes, it crept inside and freeze. Penguin chicks see how unfamiliar
waitoreke had shielded weak light penetrating into the nest chamber. They have
got into the most distant corner of the hole and have calmed down. In fact,
they have nothing to be afraid of – the stone under which the hole is made is
also a ceiling of the hole and protects their dwelling reliably from caving-in.
And even ruacapangi can’t dig out their hole.
Ultradamas have herded fawns together and have continued the descent to water.
Waitorekes fed in the river, and also adult penguins have seen, how these majestic
animals were left from the forest. Adult ultradamas have lowered heads to water
and began to drink by long gulps, from time to time raising heads, looking around
and smelling air. Fawns have finished drinking much faster and began to race
at the shoaliness, raising legs high at each jump. Scared by their occurrence,
one waitoreke has emerged and has uttered loud disturbing whistle. Ultradama
fawns have shuddered with unexpectedness when near to them its loud voice was
resounded, but have calmed down, when tiny beast has swam away and has dived.
One adult doe has stepped in water and has moved through thickets, lifting sand
and silt from the bottom. Long leaves of water plants represent the favourite
food for these herbivores, and they frequently come to small rivers to regale
themselves with sappy greens. Adult doe has grasped by lips and has pulled out
from water the whole bunch of plants. Having shaken it up, deer began to chew
soft greens. Fawns, seeing what it does, also have wanted to taste this delicacy.
But they hadn’t manage yet to get these plants as dexterously, as adults do
it: one fawn has lowered head in water too deep and began to sneeze, when water
has got into its nose, and the second one managed to pinch off some leaflets.
But their taste appeared good for it, and fawn began browse the leaves waving
on surface of water.
Ruacapangi male also has gone down to the river at the distance from ultradama
herd. It sees large adult ultradamas and is not going to attack on fawns. Nevertheless,
at its presence one doe has walked along the riverbank, keeping between the
bird and fawns, and the doe walked in the river stopped feeding and has made
some jumps in water in its direction, making a cloud of splashes. Both females
show the intention to protect juveniles: they utter loud low and stamp front
legs. Ruacapangi male has stepped back from water and has disappeared in bush,
and deer have continued feeding in shallow water. It seems their appetite may
destroy fodder areas of waitorekes, but in fact it does not occur: deer thin
thickets of aquatic plants, enabling fresh greens to appear and interfering
with accumulation of silt near the riverbank. Therefore their presence is only
an annoying obstacle for waitorekes’ normal life, but nothing more. Consequences
of their stay will only improve conditions of life for these beasts.
Spring gradually finishes. Every next day becomes hotter, and soon there will
come humid New Zealand summer. Life of underwater inhabitants takes its normal
course, and there are important changes in it. Neohanasaki juveniles hatched
this year gradually grow up. Many neohanasaki tadpoles were lost after males
have ceased to care of them, but it is quite natural loss of posterity. And
neohanasaki adults also have contributed in extermination of their own posterity.
Survived tadpoles of this kind do not remain in lake – for the period of growth
they migrate to the small forest rivers where there are no adult relatives representing
considerable danger for them. These creatures already differ from tadpoles of
frogs in larger sizes and the lengthened body. Small neohanasaki at this age
already differs considerably from the creature just released from fatherly trusteeship.
At this one legs already develop gradually; at first hind legs develop, and
it gives out the relationship of New Zealand false salamanders with tailless
amphibians. Front legs represent now only lumps covered with thin skin. But
already in such early age neohanasaki tadpoles are predators, and due to the
diet they grow quickly. Their task is as soon as possible to pass a dimensional
category in which they are vulnerable for the majority of predators of fresh
waters of New Zealand.
The small tadpole neohanasaki arranged an ambush in shallow water under roots
of the tree fallen across the forest stream. The roots sticking out in water
are partly ground off by snails and crustaceans, but form good shelter for this
animal: alternation of light and shadow completely hides this tadpole. Having
clung by hinder legs to one root, it simply waits while prey of suitable size
will swim up close enough to be seized. Small eyes of neohanasaki tadpole look
upwards and partly in sides – from shadow it watches a site of surface of the
water covered by sunlight penetrating through forest canopy. Here microscopic
crustaceans swim like smallest dots, and fish fry hunt them. The tadpole should
not emerge to surface of water for air – while it breathes using internal gills
which completely provide its requirements for oxygen. It needs to wait only.
Small fish fry form large shoals. Most likely, this is posterity of any kind
of galaxias or cyprinoid fishes descended from any species introduced by people.
They rush near the surface of water, from time to time sparkling by silvery
sides. Fry eat, among others, small insects falling in water, therefore everything
that the river carries causes interest in them. But some insects can hunt fishes.
The neohanasaki tadpole sees how sparkling shoal of fry suddenly rushes in all
directions, and on their place the oval silhouette of the clumsy water beetle
appears. When the insect swims away, fry shoal gathers again – at first separate
individuals, but then shoal gathers again approximately in the same number.
When fry have continued search of food, small neohanasaki has cautiously let
off a root, for which it kept, and slides smoothly to fry shoal. Its movements
are slow and cautious, therefore fry have suspected of nothing. Colouring hides
neohanasaki tadpole on the background of the flooded tree, therefore its attack
on fry was unexpected, and therefore successful. The neohanasaki tadpole managed
to seize one fish juvenile, and the small predator has immediately swallowed
it entirely. While it should be content with small prey, but in due course of
growth prey will become larger also. Though now the tadpole neohanasaki is so
small, that it may become easily anybody’s prey itself. At early age the tadpole
neohanasaki has more chances to be lost than to survive: up to an adult condition
only separate individuals from many tens of them survive.
Having swallowed fry, neohanasaki tadpole has returned to an ambush. It has
hooked by rear paw against root to have a rest and to digest prey… but near
it the wide mouth opened wide, current of water has torn off a tadpole from
the root and young neohanasaki from last year’s hatch had literally soaked up
its smaller relative entirely and has closed mouth. Tip of prey’s tail sticking
out of its mouth still twitched, but then has disappeared. This creature already
resembles adult individuals in greater degree: both pairs of its legs are advanced,
and the body gradually gets the shape characteristic for adult individuals of
this kind, though its stomach is still convex, as at a tadpole. Length of this
young neohanasaki is only about 15 centimeters. Such creature has much more
opportunities for survival, though it is also necessary for it to be cautious
and to keep in depth not to fall casual prey for any predator.
Young neohanasaki has swum down under tree trunk, and has simply lain on bottom
in shadow. Now it is difficult for making out from surface of water, and other
inhabitants of the river are perfectly visible to it. If it will be lucky enough,
in some years it will return in lake and will can take part in courtship games.
But for this purpose it needs not to leave a safe channel of the river for some
years.
Rangitahi tadpoles have considerably grown up and have got a recognizable appearance
characteristic for this species. They have slightly lengthened cylindrical body,
very big tail bordered by fin plica and strong sucker-like mouth. They eat algal
films and sedentary animals, and during the rest hang on stalks and floating
leaves of plants. In case of danger they are able to seek safety in flight and
dexterously bury themselves in silt. But their behaviour begins to change gradually:
if earlier they were hidden in warm gulfs and did not avoid water stagnant and
poor in oxygen, now rangitahi tadpoles leave their native places and keep in
sites of lake with cool and clean water. They gradually have “reassessment of
values” in relation to choice of habitats: they have grown up and prepare for
the first migration in their life, therefore previous forms of behaviour fade,
and the next ones are expressed clearer. Now they are involved with a smell
of river water and current. At this age rangitahi tadpoles already prefer to
keep in parts of lake where current of the rivers running into it is felt. Some
tadpoles by mistake swim in forest rivers and cannot get out of them, following
instincts blindly, and soon perish, becoming prey of river predators. But the
most part of rangitahi tadpoles finds the aim correctly: shoals of these creatures
gather in thickets of underwater plants in mouth of the river flowing from mountains.
It has returned into the channel a long time ago, and its current became smooth
again. Now the river became convenient way for travel, and tadpoles move in
mountains – in place where they will spend almost all further life to return
for the short time to native lake to give life to new generation and to die.
The smell of water of the mountain rivers involves tadpoles, and positive rheotaxis
forces them to move against current. Primitive reactions to conditions of an
environment help them to make long and difficult travel. At the whole extent
of the way they will come to overcome current and to avoid meetings with predators.
Rangitahi tadpoles are very fine; therefore they have a lot of enemies. They
are saved in part only by their large number and skill to disappear in narrow
cracks, from where the predator will not get them.
For a way to upper course of the rivers small rangitahi tadpoles should swim
through places where native thick-lipped carps live. By the end of spring these
fishes already spawned eggs and new generation of thick-lipped carps grows up
in secluded places among stones where adult individuals will not reach. Young
thick-lipped carps also win to themselves fodder territories from relatives
and express aggression to everyone leading a way of life similar to them.
Rangitahi tadpoles migrate upstream, keeping coastal shallow sites. Here current
is not such strong, and it is easier for them to swim. But here young thick-lipped
carps gather and between them and tadpoles conflicts for territory flash. Tadpoles
are only temporary visitors of these places, and fishes do not understand it;
therefore they defend the tiny fodder sites as actively, as adult individuals.
But rangitahi tadpoles move above the bottom in numerous shoals. The distance
between separate individuals sometimes happens shorter than the length of the
tadpole. Along the column of tadpoles as if run waves: forward lines of tadpoles
almost synchronously come off the bottom and make a forward rush, and then fall
on the bottom again and attach to stones by sucker to have a rest and to scrape
off anything edible. The individuals staying in back lines repeat their movements
with some delay, and it creates an effect of the wave running along the column.
While the individuals moving in rear-guard of the shoal finish their movement,
the avant guarde of shoal already prepares for a new forward rush.
Young thick-lipped carps break the coordinated movement of the column, attacking
on tadpoles. They behave like adult individuals, exposing to tadpoles the stretched
fins though they have not got adult colouring. Signals of fishes mean of nothing
to tadpoles, therefore they continue the movement, indifferently swimming past.
Some of young thick-lipped carps scare them away with impacts of heads, but
the live stream of rangitahi tadpoles only parts on safe distance from aggressors
and continues movement.
Rapids in upper courses of mountain rivers appear more serious obstacle for
small travelers. Rangitahi tadpoles feel smell of water of the mountain rivers
attractive to them and also strong current, and it serves for them as powerful
stimulus for moving ahead. In the beginning of spring the same rapids became
an obstacle for shoals of eversmolts moving to spawning areas, but fishes have
overcome them though have wasted many efforts for it and have left behind the
rapids some weakened, wounded and perished individuals. For rangitahi tadpoles
thresholds represent the even greater obstacle: they are too small and weak
to overcome such obstacle with jumps. But the kin of rangitahi frogs does not
interrupt, as tadpoles use different tactics for overcoming river rapids. The
thing which in other cases becomes a source of troubles helps them in this hard
work: it is the small size. Eversmolts overcome rapids by moving in places where
the fish of their size can swim. But in these places, as a rule, the current
is strongest. Rangitahi tadpoles act differently: they squeeze into narrow cracks
between stones where current can be not such strong, and sometimes simply bypass
rapids at the edge, moving on wet stones and having exposed backs from water.
The big advantage at this stage of travel is strongly extended body shape lowering
the resistance to stream of water in which it is necessary to move, and allowing
squeezing in the narrowest cracks between stones. In some places tadpoles slowly
creep on surface of stone, attaching by oral sucker and moving ahead by short
lunges alternating to the long periods of rest. Not all of them succeed to resist
the current: the stream of water tears off some tadpoles and carries them downstream,
forcing to overcome an obstacle from the very beginning. Some tadpoles are floating
downstream, helplessly tumbling in water: they were stunned by impact against
stones and cannot resist to the stream of water. Some of them cannot rise over
rapids anymore and, most likely, will become victims of river predators. Others,
however, quickly “come to the senses”, rush on bottom, hide between stones and
have a rest. Sometimes they succeed even have to have some meal. But then they
swim again to rapids and desperately attack this obstacle. Rise over rapids
is a serious test for small tadpoles, but sooner or later the obstacle appears
behind, and there comes the final stage of travel.
Not all rangitahi tadpoles can reach places where will spend almost all their
further life. The part of them perishes at rise over rapids; another part receives
wounds and further dies from infectious diseases. And someone becomes simply
a victim of predators. Too small rangitahi tadpoles will hardly become prey
of New Zealand false raven or other carnivorous bird. But they may be easily
eaten by dragonfly larvae or water beetles, let alone fishes.
In the mountain rivers of New Zealand there are not so many species of fishes,
but the most typical representatives of local ichthyophauna are eversmolts.
River forms of eversmolts differ from lake ones in features of colouring and
in smaller size, but frequently in their schools separate representatives of
the lake form stay. These fishes for various reasons are late in the river after
spawning. Usually these are individuals which have received wounds during the
migration to spawning areas and have simply remained in cleaner river water,
waiting while wounds will be healed. On sides of such fishes there are visible
healed scars or the places covered with deformed scales – these are consequences
of rough spawning or unsuccessful attempts to overcome river rapids. Now fishes
restore forces, and feeding on tadpoles promotes it very much. Large rangitahi
tadpoles, that are ready to a metamorphosis, can be larger, than adult eversmolt
is, but each of such lucky beggars managed to survive and to bring up is paid
by tens individuals becoming victims of predators.
In upper courses of rivers rangitahi tadpoles travel not in numerous shoals
as in the beginning of the travel, but in small groups. Different schools of
tadpoles choose for life the different rivers and streams, and from the numerous
congestions gradually the groups numbering only of some tens or hundreds of
individuals rest. Having reached the streams, they settle in a channel, choosing
for themselves suitable shelters and fodder territories. They should be afraid
of larger relatives who can easily swallow them, therefore, when the large rangitahi
tadpole is swimming in stream, smaller individuals are ready to vanish literally:
they are hidden at the bottom and squeeze into cracks between stones, where
they are difficult for getting.
Spring comes to an end. Days are already warm as in summer – as far as the winds
blowing from ocean allow it. And one more creature, obeying its instincts, aspires
to give life to new generation of the kind.
The flat scaly head has seemed from under water among thickets of water plants.
It has only touched a surface of water with a tip of snout as skin valves above
nostrils were slightly opened, letting air out with silent hissing. Having made
a breath, the animal has dived and among plants its body of grey color with
thin white cross strips slides. Female of marshland aotearophis has felt that
there comes time to lay eggs. Now its task is to choose a place for nest where
eggs would be protected from casual predators and would successfully pass the
incubation.
The reptile easily slides in thickets of water plants. It does not hunt, therefore
does not pay attention to waitoreke body flashed among plants. But for these
beasts such creatures represent obvious danger – it happens, that some
local reptiles visit waitoreke colonies for hunting for their juveniles.
One more waitoreke has noticed the snake swimming to the riverbank. It was put
out from water and has whistled sharply. Its voice had been listening by some
more individuals, which at once have disappeared in coastal thickets.
Female of marshland aotearophis does not hear voices of waitorekes, but feels
waves which spread in water at the movement of these animals, and also feels
their smell. It is not going to hunt them – waitorekes are not included into
its diet. In addition now the feeding behaviour of this reptile is suppressed
– it searches for a place for egg laying. The snake, wriggling its body, slides
at the shoaliness near the surface of water. It has weak sight; therefore it
cannot notice in time the predators attacking from above. On land, and also
at the distance from a reservoir, female of marshland aotearophis would become
easy prey for such birds, as eagle kea, ruacapangi or New Zealand false raven.
It can protect itself from them with the help of poison, but speed of reaction
of bird frequently predetermines the success in such duel. Now its problem is
to be imperceptible. Dim colouring helps this reptile to hide, and the snake
creeps out on land among thickets of coastal plants to remain for shorter time
at the open place. Having got warm at the shoaliness, the reptile has cautiously
got out on the firm ground and has crept to the nearest thickets which it vaguely
distinguishes in front of head. Now it does not feel yet the vibrations of the
ground indicating the presence of large animals, and continues creeping farther
from water.
Having gone deep in forest, the reptile prefers to hide under the cover of fern
fronds and among bushes. It creeps cautiously, frequently raising head and putting
out the doubled tongue to catch a smell of the probable enemy. But it does not
notice how it comes nearer to waitoreke colony. The smell of waitoreke is familiar
to this reptile – it more than once met these beasts at the river, and waitorekes
preferred to let it pass, being afraid of aggression on the part of the snake.
Therefore the smell of waitoreke colony does not seem dangerous for snake, and
it safely creeps to the territory populated with these small beasts. It has
crept near one of holes, and receptors have informed it that the smell emitting
therefrom is not similar to usual smell of waitoreke. The snake stopped for
a moment, testing the smells emanating from this hole; it has caught a strange
smell of an unfamiliar creature to which the strong smell of fish of different
degrees of freshness is added. Not having felt anything dangerous to it, the
reptile has crept forward – in direction from where the distinct smell of waitoreke
was felt.
Penguin chicks already have almost reached the size of adult birds. New Zealand
mountain penguins are birds of the small size, therefore development of chicks
at them is much faster, than at the kinds lived on the Earth in human epoch.
Juveniles behave very actively – they will become adults soon, and it is a proper
time to them to get acquainted with world around much closer. While parents
fish at the river, juveniles wander over waitoreke colony, looking into the
holes of their neighbours. If grown up waitoreke cubs try to seize their tails,
continuing the games, young penguins repulse them: they chase for young waitorekes,
having stretched wings wide and screaming loudly, and have not always time to
stop, if their way is crossed by adult waitoreke not going to enter their game
at all. Waitorekes got acquainted to penguins for a long time and do not perceive
them as enemies: they simply relate neutrally to their presence. But the playful
young penguins risk receiving repulse from an adult animal: the adult waitoreke
dissatisfied with too rough games displays its incisors, and this expression
of displeasure forces penguins and young waitorekes to stop their noisy games.
Female of marshland aotearophis has crept to the territory of waitoreke colony,
and its occurrence was noticed at once by one of adult beasts. It has uttered
shrill whistle, warning its relatives about danger, and all animals remaining
on the ground surface have disappeared in holes. It was far from being best
tactics of protection somewhere at the continent where snakes can eat rodents.
But aotearophis is a herpethophagous species and it may represent any danger
for waitoreke only when it would not possible for two animals to miss each other.
The alarm signal has found young penguins too far from a native hole. They well
know what does such sound mean, therefore, having heard it, they have rushed
to the hole in which were always hidden in case of danger. But on their way
there was a strange creature which they are seeing for the first time in their
lives – it is long, coloured grey with white cross strips. It is absolutely
legless, but thus can move on the ground and can bend. Having noticed young
penguins, this creature has raised head and has opened mouth in which the set
of the thin recurved teeth sticks out. It has hissed and began making fast jerks
by head aside birds, having forced them to move back.
Aotearophis female has unexpectedly faced a new obstacle. These two creatures
which so suddenly appeared at its way are unfamiliar to the reptile – it seldom
faced with New Zealand mountain penguins, and even less often with their juveniles
which have not replaced yet the down dress to adult plumage. But their smell
is very similar to what the reptile has felt while crawling by one of holes.
These creatures are not going to attack it and make way to it, but make it too
slowly. The reptile crawled into ball, continuing to display its opened mouth
to them, and then has made a rush and has poked with its muzzle into one of
these creatures.
After the poke the young penguin was tumbled down on the ground, and the second
chick has rushed to run. The fallen chick has loudly shrilled and began pulling
legs and wings, trying to turn over and to stand again. And the snake, seeing
jerky movements, has apprehended them as aggression and has hissed. It was ready
to put the second impact when has felt an acute pain in body.
Mother of juveniles appeared there just in time. It has run up to snake from
behind and has strongly pinched it by beak. When the reptile was turned around
to her, the penguin female has run off aside, and at this time the fallen chick
has stood up, has run off aside and has hidden behind the root of tree. Penguin
female has remained face to face with the large reptile, which haves deadly
poison in addition. The snake is too sluggish now, and is not going to hunt.
Therefore the penguin female at certain dexterity can escape even during the
conflict to such dangerous enemy. But she does not know about it and is not
going to estimate its own opportunities: it comes to her posterity, and the
parental instinct stimulates her to protect her chicks from the reptile. Therefore
she has simply run off aside and has rushed to the snake again, putting it the
impacts by beak. Attacking the snake, the penguin female shrills loudly – she
acts the same way as her relatives act during the joint attack on any predator
like New Zealand unbadger. But now she does it alone and can expect only for
herself. However, her force so is strong, that the reptile has to recede. The
snake does not hear bird’s calls, but feels pain in body from impact of her
beak, and it forces reptile to pull after each impact.
Penguin female is obviously tired – she breathes deeply and reels. But the enemy
is still here, and she is obliged to continue to drive it away, even being alone.
Her voice loudly sounds in waitoreke colony became silent of fear, and soon
she has heard well familiar answer to her voice – male had returned from fishing.
His occurrence appeared very appositely – female’s forces are already close
to exhaustion, and the snake creeps away too slowly. When the reptile has once
again turned head to penguin female, it has suddenly felt a pain with fresh
force – male had literally seized its scaly skin by beak and has sharply pulled
it. Having turned to the new opponent, the reptile appeared vulnerable for penguin
female, and she at once has pecked it in turn. Advantage appears on the side
of penguins. Birds are adjusted resolutely, and it pays off: the pair of penguins
in common banishes the snake from territory of the colony.
Birds have won. They stand among waitoreke holes, panting and looking around.
And somewhere at the distant edge of the colony the snake’s tail disappears
among ferns. When it was gone from the field of view, female has uttered short
inviting signal, and two young penguins, pushing each other and waddling, has
run up to parents. The enemy has left, peace life proceeds, and now it is just
a proper time for chicks to have a meal. They shrill impatiently, and both parents
widely open beaks, enabling juveniles to regale themselves on the fish brought
for them.
At this time from holes waitorekes begin to appear. First they only look out
and smell air cautiously. But gradually waitorekes turn brave and get out of
holes. Some young animals smell the ground on which the snake crawled – they
remember a smell of the enemy to distinguish and to avoid it in the future.
Danger was passed and waitoreke colony comes to life again. It seems that penguins
are not so bad neighbours though they are not similar to waitorekes.
Marshland aotearophis female is wounded – in one place its skin is broken off
by beak of male penguin. This wound hurts, but it seems it is the only one.
In other places the pain of beak impacts gradually fades. The parental instinct
has prevailed again, and the snake began to search for a place for the future
clutch. It captiously tastes air with tongue, trying to find the best place
for the future progeny. The reptile creeps by the stony sites of the ground,
preventing to dig out the nest, and by the big stones which only cool ground
with their mass. After long searches it has found out such place – it is under
roots of the large tree. The ground at its bottom is covered with a layer of
fallen foliage and is mellow – it is ideal for the nest arranging. It is difficult
for legless reptile to dig out a hole, and aotearophis female should work hard
to make it. By movements of front part of body it began to rake off the layer
of foliage and the ground, and soon wide hole of suitable depth was formed.
During its work female stops some times to have a rest, and then continues the
work. From time to time it crawls back and tries the smell of the dug out ground
by tongue. When it seemed to it that everything is ready, it turned to the ball
at the bottom of hole and began to lay eggs. One by one in the ground six eggs
with soft leathery shell have fallen. Having got free of them, the snake has
felt much more freely. It began to creep around of the clutch, raking up the
ground and foliage atop of the clutch with lateral movements of its body. This
work had taken from it about half an hour. Having finished it, the reptile has
simply crept away in bushes and began to search for a way back to the river.
The destiny of the laid eggs does not interest it any more. Maybe, one more
female will lay eggs in the same place, even having dug out another’s clutch,
and it is possible, that any predator would simply find a clutch and would destroy
it in hour, day or week. It does not interest the snake any more: it has made
everything that the parental instinct needed from it.
After the meeting of penguins with the snake about one week passed. Young penguins
have matured enough to leave for the first time a colony which represented the
whole world familiar to them before. In addition some days ago they have started
to shed down, and now became more similar to parents. At them black juvenile
down had already moulted almost completely, and instead of it they have smooth
plumage now, white on stomach and brown on back. Only on shoulders and neck
of young birds there are appreciable fragments black down, and their beaks are
not such bright yet, as at adult birds. In the rest young birds are completely
similar to parents. Waitorekes are not confused at all with such change in shape
of young birds: their smell has remained the same, and waitorekes trust the
sense of smell more, than sight.
When adult penguins have gone to the river at that significant day, one of young
penguins has simply followed them. The second chick wanted to remain in the
colony, but, having seen, that the first young bird leaves, it has cried, has
waved wings and has rushed after it. Parents have not paid attention to actions
of their posterity: they always returned to the colony, and chicks always waited
for them there. But now, having casually turned back halfway to the river, female
has seen that both young penguins follow her, waddling and keeping balance by
means of wings. Female has only waited for them a little, and when young birds
have overtaken her, she has continued a way to the river.
Young penguins look around curiously: the world appeared much larger than one
to which they have got used, constantly staying in a colony. They curiously
look at tops of trees, try to peck small beetles creeping in grass, or pluck
off small white flowers blossoming in shadow under fern fronds. Keen on knowledge
of world around, they have not noticed, how have left to the riverbank, and
have understood it only then when the track turned downwards sharply and they
have slid on it, not having kept balance, almost to the edge of sandy beach.
Parents have waited while young birds stand, and then have come in water and
have confidently swum along the pass in the thickets made by waitoreke. Young
birds do not hurry up to follow them. One chick has cautiously stepped into
the water, but almost at once has run back and began to shake off. The second
juvenile has also tried to enter the river and has returned to land, and then
has put beak in water and has sneezed, when water has got to its nostrils. They
are not ready yet to follow parents, and they still need to learn not to be
afraid of water and to feel like confidently in this element new to them. While
young birds wander on the land, forcing their way through thickets of marsh
plants.
While some inhabitants of the river make the first shy steps in water, others,
on the contrary, leave it and master for a short time the elements which will
never be subdued to penguins. Day when young penguins have seen the river for
the first time is absolutely special – it happens once a year only. Tens of
thousands of tiny six-legged creatures have left the former habitats at the
bottom of the river and have gathered in thickets of coastal plants. These are
mayfly larvae preparing for the first and last air dance in their life. Waitorekes
which has had the luck to appear at the riverbank at this time, snatch greedily
easy and defenseless prey which, it seems, creeps in their mouths itself. And
under water from the river bed silt rises – fishes swim up to the coast, gathering
mayfly larvae creeping on the bottom. Sometimes the silvery side of the fish,
which have swum up almost to the edge of water in attempt to overtake prey creeping
away, sparkles in muddy water. But all the same larvae are numerous. Their number
is too great to be exterminated by all predators taken together. In addition
they appear from their shelters simultaneously, and predators will not manage
to exterminate all of them.
Brownish creatures creep out on leaves and stalks of plants, and hang there,
keeping for a support only with tips of legs. They undergo a magic transformation:
brownish skin bursts on back, and bright green translucent creature with two
pairs of wrinkled appendages on back gets out of crack. It hardly makes some
steps, leaving its old shell, and hangs on plant, undergoing new transformations.
The wrinkled appendages on its back get smoothed back and turn to wings – back
ones are short and rounded, and front ones are much larger and lengthened, with
rounded tips. At the tip of abdomen three thin threads, which length appears
approximately equal to the length of body of an insect, fall out at this time.
The first moult is followed at once by the second one: it is a tribute to an
ancient origin of mayflies, which has remained also in Neocene epoch. And only
after that winged creatures rise in air to meet each other and to die up to
a sunset.
Mayfly flight at the river is the almost fantastic show showing the actual scale
of productivity of such ecosystem. At first in air only tens insects flit, and
some wood birds fly by above the river, seizing them right in flight. But with
each hour there are more and more mayflies: simultaneously above riverbanks
hundreds of thousands and millions of insects fly up. The blizzard of insects
literally storms in air, despite of birds piercing it like arrows. At each mayfly
only tips of wings touch each other slightly, but insects are so numerous, that
a rustle of millions of wings softly, but reliably muffles all other sounds
around. After pairing mayfly males literally fall down: they have executed their
duty to the species, and now they are waited with old age and death promptly
coming nearer. And females scatter above water incalculable set of eggs, giving
life to new generation of insects which in two-three years will also perform
an air dance of love and death above the native river.
The feast of predators takes place not only in air, but also on the ground and
in water. Dying mayflies cover with their bodies land and surface of water.
Young penguins walk on the riverbank and peck greedy the fallen insects. Near
to them on land waitorekes run and small birds of various species hop, and somewhere
in the distance the pair of New Zealand false ravens fills stomachs hasty with
a gratuitous entertainment.
Everywhere at the surface of the river under the live cloud of mayflies hovering
in air water splashes: fishes also take part in feast. Schools of small fishes
seize the insects fallen in water and drag them in various sides, gradually
tearing them off, and larger fishes swallow mayflies entirely. The striped or
spotty back flashes, a small whirlpool appears on the surface of water, and
the insect disappears without any trace. And other fishes show their acrobatic
abilities: adult ‘ika-kaihopu live-bearers jump out from water to the height
of one meter, dexterously seizing mayflies right at flight. And among thickets
of water plants long spotty bodies of small fishes from time to time flash:
rahirahi galaxias also eat mayflies. They do not come up in open water, but
dexterously move among leaves and stalks of plants, turning upside down and
seizing from below the insects floating on the surface of water.
Young penguins approach to edge of waters and gather dead mayflies. One of them
has pecked up several insects too hasty and has had a fit of coughing, having
choked with their thin dry wings. It may not hurry up: the amount of entertainments
would be obviously enough for everybody. But even being at such feast it is
better not to forget about care: the nature always reminds, that the enemy may
hide somewhere beside. On surface of water the big fin has struck, and then
from under water the huge head with the big yellow eyes and widely opened mouth
has put out – the adult ‘ika-taikaha also has taken part in eating of gratuitous
entertainment. As soon as this creature has marked its presence, some waitorekes
from the riverbank uttered alarm whistles, and some more beasts appeared in
water, have immediately got out on firm land. Young penguins see this underwater
monster for the first time, but disturbing voices of waitorekes are well familiar
to them, therefore birds also run off the edge of water and cautiously look
at the surface of water.
Adult penguins come back from fishing, having filled stomachs with small fish.
They emerged on the surface of water for some times and had seen how above the
river the huge cloud of mayflies hovers. They also met the fishes swimming near
the surface of water and engulfing the insects fallen in water with loud smack.
But they have found out the presence of huge ‘ika-taikaha even earlier, than
waitorekes swimming near the riverbank. Penguins saw how this fish directed
to coastal thickets and have decided to get out on land in the other place.
The huge fish swimming at the shoaliness represents a real danger to such small
penguins.
Not all inhabitants of the river have apprehended the appearing of ‘ika-taikaha
as a threat. Dexterous and mobile ‘ika-kaihopu live-bearer continues to catch
insects, jumping out for them from water. Almost each jump of fish appears remunerated
by prey, and sometimes it succeeds to seize even two insects in one jump. Successful
hunting has dulled care of this fish: it is not known, what can take place while
the fish is in jump. And during the next jump of ‘ika-kaihopu for prey below
it from water the huge head of ‘ika-taikaha has appeared. The predator has only
opened mouth wide, and ‘ika-kaihopu has fallen down into its teeth. Jaws closed
immediately and very strongly, the striped back of predator has flashed among
water plants and the strong tail has splashed on water. The huge fish left on
the depth, pacified by temporary feeling of satiety.
The live cloud of mayflies still hovers above the river, but the culmination
of breeding flight of insects has already passed. On surface of water thousands
of dying insects float, and the river bed and underwater plants are covered
with a cover of the smallest eggs of these insects. Lots of eggs and larvae
of mayflies will be lost during the next days and months, but in two-three years
survived larvae will turn to imago and will also perform their last dance above
the river.
Hobbling clumsily, adult penguins come back to their chicks which have stayed
on the riverbank. Would these birds have more emotions, they could be surprised
to that young penguins do not run to them and do not ask for food. Juveniles
are glad to returning of parents, but only one of them has languidly asked for
fish at female. The second one has not taken a look at this fish at all: its
stomach is filled with mayflies which they managed to peck up at the riverbank.
Perhaps, it is the first day from the moment of their hatching when adult birds
could be full.
The last mayflies have finished their flight shortly before a sunset.
Rainy New Zealand summer has come. Young penguins have gradually lost fear of
the water and have begun to master this element new to them actively. They have
completely left their juvenile down and only dimmer colouring of beaks shows
that they are not adults yet. They are not afraid of water any more, as earlier,
but now still prefer to swim along the riverbank to have an opportunity to leave
water at once in case of danger. They are already familiar with local species
of fishes and try to gather from bottom insect larvae, looking at waitorekes.
From time to time young penguins follow adult birds and swim to the middle of
the river channel, but nevertheless feel like not so confidently yet and quickly
turn to land. The first hunting successes of young penguins are still modest,
but these birds already succeed to catch young ‘ika-taikaha fishes hiding in
thickets and even to chase small fishes in thickness of water. Parents already
feed them less, and soon they will come to rely on themselves only.
Famine is a good teacher; therefore in two weeks after the young penguins appeared
for the first time at the river, they began to provide themselves with food
independently. Their connection with parents turned weaker considerably – now
they perceive their parents exclusively as congeners to which society it is
necessary to adhere. Young penguins did not begin to leave from waitoreke colony,
but one by one they have left parental hole and have dug out their own dwellings
nearby.
Many inhabitants of the rivers and lakes of New Zealand breed in spring. Incentives
for this purpose are the increase of length of light day and thawing of snow
in the mountains, and also changing of chemical compound of water. But some
inhabitants of New Zealand rivers submit to other stimulus: the rhythm of their
life is set by the Moon. Shortly before the beginning of syzygial tide the migration
of rahirahi galaxias to spawning areas begins. These fishes live in many rivers
of islands, but they live in fresh water not the whole life: the first months
of their life pass in the seas washing the coast of archipelago.
If migrations of eversmolts or rangitahi tadpoles are difficult for not seeing,
rahirahi galaxias migrate for spawning very silently and imperceptibly. These
fishes do not like to remain visible for long – many predators apply for prey
of just such size. And their migrations take place at night. Small schools of
fishes move in the river channel, choosing deep and dark places where they are
more difficult for noticing. In case of danger fishes instantly hide in sand
and silt, or squeeze in cracks between stones. The rivers of New Zealand are
short; therefore they reach the sea only for one or two nights. There these
fishes will wait for high syzygial tide, when the wave will cover sandy shallows
in rivers mouths. In these places hardly covered with a tidal wave, rahirahi
galaxias will dig in sand by tails vertically and will spawn eggs, leaving them
in safety up to the next inflow. And the posterity of these fishes will appear
in the rivers only in the beginning of winter, if they will survive for some
months in the sea.
In waitoreke colony young penguins have perfectly accustomed with all difficulties
of adult life. While they do not have occasion to leave this colony and to search
for new places for life – the river provides their needs for food, and here
it is less number of large predators compared to lake upstream. Young penguins
are acquainted with ‘ika-taikaha monsters and prefer to swim far away from places
where these fishes hide. Now they succeed to avoid meetings with these predators,
but it is not known what may happen the next day, therefore the survival of
this group of penguins without contact to the main colony hangs by a thread.
It is enough to perish even to single birds, and the survival of this population
of penguins would appear in doubt, and unexpected natural experiment with formation
of a colony of two species of animals would be interrupted. But penguins, as
well as waitorekes, live only by the present moment, not thinking about the
future.
Every day young penguins swim downstream farther and farther. They have learned
to use a watercourse to reach places of fishing, and have learned to choose
places to swim against current, spending as small additional efforts as possible.
They have obviously accustomed in the river better than their parents, and hunt
more successfully. Distant excursions bring one more benefit: fishing areas
are not exhausted and penguins always have food. But there are days when stay
at the distant fishing areas brings something greater than simply full stomach
of fish.
Young penguins dive for fish together. Using current and force of their own
wings, they gather the great speed under water, pursuing school of silvery fishes.
It is not so convenient to drive schooling fishes and to keep them far from
shelters when there are only two hunters. Birds should pursue each fish which
they want to eat. But it is costs of their small number which should be taken
for granted. Penguins, however, get out of this difficulty, compensating the
small number in the speed and dexterity. They do not give fish school to come
nearer to the riverbank where they can hide among plants, and seize fishes one
by one. Their tactics bears the fruits, but suddenly fish school swims off in
all directions and many fishes managed to escape from the chasers. The panic
of fishes has forced penguins to interrupt hunting and to look round. They at
once have seen the originator of a fright of fishes. It does not hide, but also
does not attack: it is not a predator, but the congener. But it is not anyone
of parents of these birds, but absolutely unfamiliar bird, the male. The stranger
does not try to swim away and does not show any aggression – it obviously wants
to remain with young penguins. Its beak already gradually began to get red colouring
characteristic for beaks of adult individuals. This single is a “tramp” moved
from the colony living in other mountain valley. It has simply abandoned the
valley and has gone down the river and then spent a long time in wanderings
in searches of congeners. When two young penguins have swum to the colony, it
has followed them, trying to keep abreast and not to lose track of them. When
birds have come nearer to the colony, the first ones they have met were some
waitorekes searching for food at the shoaliness overgrown with plants. Old residents
of a colony have not paid any attention to them: they have got used to the society
of these beasts from their hatching. And the newcomer, being older compared
to them, has cautiously related to these beasts. But it has seen how its congeners
have got out on land and after small hesitation has followed them and also has
left water. Birds have walked three together on one of the footpaths leading
to the colony. When they met one waitoreke, young birds have simply passed by
it, and the newcomer has slightly bent down forward, has extended neck, has
spread wings and has opened its beak wide. Waitoreke has shuddered and has made
way for unusually aggressive creature. When the penguin has passed by, it has
smelt its traces and was directed further to the river. It has already got used
to strange biped neighbours and knows that these display acts usually have no
continuation.
Penguins have reached a colony. Young birds have at once disappeared in the
holes, having left the newcomer alone. It has looked round and has seen numerous
holes, as in the colony of congeners which it has abandoned once. But it has
shuddered with unexpectedness when from the nearest hole waitoreke has got out
and has safely approached to it to smell. This penguin had never met waitorekes
so close, and their presence here, and moreover in a plenty, disturbs it. But
from one hole at the edge of the colony the voice of one more penguin suddenly
was heard, and two its relatives have got one by one out of the hole under bush
– they are a pair from which this strange union of penguins and waitorekes began.
These old residents waddle to get acquainted with a new member of the colony.
Their presence has reconciled a little the new male to waitoreke neighbourhood:
if there are congeners here, it means that it is possible to live in this colony,
even if the majority of it is made with the strange shaggy beasts looking unlike
penguins. This male will learn to coexist with waitorekes in the future, but
the main event for it is a meeting of congeners. If it will be possible for
birds to coexist further with waitorekes successfully, it will give rise not
only to new colony, but also to new relations with neighbours in common habitat.
And it is quite possible, that it will be a new step in evolution of not only
one, but of two species of animals at once.
Bestiary |
New
Zealand mountain penguin (Microsphenicius pusillus)
Order: Penguins (Spheniciformes)
Family: Penguins (Sphenicidae)
Habitat: New Zealand, rivers and mountain lakes.
Picture by Alexander Smyslov
Change of epoch is negatively reflected in sea fauna and species
of large animals connected to it. The plankton – the basis of food chains of
ocean, and also community where various sea inhabitants spend a part of life
– is very sensitive to natural accidents. During changes in climate and geography
of planet its amount reduces sharply, that results in mass extinction of sea
fauna. Such situation had taken place at the boundary of Holocene and Neocene
when the rigorous and long ice age had changed shape and climate of planet for
a long time. Numerous species of sea animals had died out, but some ones managed
to survive, having “hidden” in fresh waters.
Among freshwater “fugitives” from plankton accident there were basically various
species of fishes and at islands of New Zealand the relic species of penguins
had lodged – it is one of last species in varied and ancient by origin order.
The New Zealand mountain penguin had kept in fresh waters of New Zealand, isolated
from typical oceanic fauna. It had adapted to life in cool lakes and rapid rivers
of islands, eating the various animals living in them. Less productive, but
more stable ecosystems had permitted to these birds to survive.
Island isolation and scarcity of food resources had an effect at appearance
of the mountain penguin: it has strongly decreased in size, having turned to
the bird about 20 cm tall. Instead of the strict black-and-white attire this
bird had got spotty gray-brown coloring of back – it is easier to the mountain
penguin to mask among a non-uniform landscape of the new native land. Stomach
is white with black cross strip on throat. Strong and muscled fin-like wings
now help not only at swimming, but also at movement on land. On the edge of
wing feathers had turned to flat corneous spikes similar to nails. They help
mobile and dexterous bird to climb on stones and to rake pebble in searches
of invertebrates. Sometimes New Zealand mountain penguin even escapes from predators,
climbing on trees with inclined enough trunk. Thus it clings against bark by
paws and wings.
Shining red beak arrests attention like bright spot on dim background of this
penguin feathering. Besides for it the bird has narrow rings of naked skin around
of eyes. In their colouring the sexual dimorphism is shown: at males “glasses”
are pink, at females – grey. Beak of the mountain penguin is short and thick.
In maxilla two short sharp tooth-like outgrowths jut out. They are using for
killing of small vertebrates containing the food of this bird.
New Zealand mountain penguin catch fish in lakes and rivers of islands, and
besides it eats water invertebrates – crayfishes and snails. As against sea
congeners of Holocene epoch, this bird had expanded a diet and eats also ground
animals – on land mountain penguin pecks insects, snails and small vertebrates
(lizards, rodents).
Similarly to all representatives of the family, New Zealand mountain penguin
nests in colonies. The size of colony depends on efficiency of habitats: near
big lakes number of colony can reach hundreds of individuals, near big rivers
up to several tens, and near small wood streams this bird nests in settlements
numbering only few breeding pairs. If fodder resources of habitats are exhausted,
birds having no nests can abandon the colony and search for new places for life.
They are able to survive in wood or to overcome watersheds in searches of new
place for life.
This penguin arranges nests in holes which it digs independently in river coast,
under protection of large stones and roots of trees. In each hole with long
common “corridor” some pairs of adult birds occupying separate nesting chambers
nest. Pairs at this species keep till all life. Nesting partners pay attention
to each other, in common equip the nesting hole and protect it from competitors.
New Zealand mountain penguins nest once a year, in spring. In clutch there are
2 – 3 large white eggs, both parents hatch them alternately within 18 days.
Eggs are laid in small hole serving as the nest, without any litter. Nestlings
hatch rather advanced, with opened eyes, covered with rich black down. Beak
at them is also black: it will gradually change color when the bird becomes
adult. Till first weeks of life nestlings sit in the nesting chamber; growing
up, they leave it and wait for parents on ground surface. At danger nestlings
and adult birds hide in hole and actively protect themselves from enemies, biting.
Young birds become able to breeding at four-year-old age, and general life expectancy
makes till 25 years.
The idea of existence of this species had been supposed by Simon, the forum member.
New
Zealand false raven (Notocorax novaezealandiae)
Order: Passerine birds (Passeriformes)
Family: Corvids (Corvidae)
Habitat: New Zealand, various landscapes.
Picture by Alexey Tatarinov
The avifauna of New Zealand in human epoch was extremely diverse,
but some families, being widespread in other parts of the world, did not live
there. One of them was corvid family. Two species of this family, Corvus antipodum
and Corvus moriorum, inhabited the main islands of New Zealand and Chatham Islands
accordingly, but have died out before the arrival of European colonists there.
However Europeans “have filled this blank”, having acclimatized rook (Corvus
frugilegus) in New Zealand. Rooks survived in epoch of ecological crisis between
Holocene and Neocene, and in Neocene the descendants of this bird, representing
the corvid family in New Zealand, occupy various ecological niches at the islands.
The largest descendants of rooks are the species of genus Notocorax, or southern
ravens.
New Zealand false raven reaches weight 2-2,5 kg at wingspan up to 170 cm. Such
size makes this kind larger than any passerine bird of human epoch, but at the
background of such Neocene giants as eagleravens it looks almost dwarf one.
At first sight New Zealand false raven resembles slightly enlarged copy of Euroasian
raven of Holocene, but there are certain differences in its appearance. Rather
long beak of this bird has conic shape without small hump above and at adult
individuals it is colored white. Birds of the first and second years of life
have beaks of black color. “Family feature” inherited from rooks is a site of
featherless skin at the basis of beak – at false ravens it is colored black
and is almost not distinguished on the background of plumage. Plumage of these
birds is black with violet shine, legs are also black. False ravens use various
sounds, but more often it is hoarse croak.
New Zealand false raven inhabits various types of landscapes – mountains, light
forests, sea coasts; it cannot be met only in dense forests. The food of these
birds is rather diverse: menu of false ravens includes carrion, invertebrates,
smaller vertebrates and vegetative food. Being mainly gatherers, false ravens
spend a lot of time, looking out for food in soaring flight or wandering on
the ground, though sometimes they purposefully hunt smaller animals. In searches
of food these birds show a high degree of ingenuity: for example, to break mollusks
shells, they can drop them on stones.
New Zealand false ravens nest on old trees. They live in rookeries numbering
no more than ten nests. Rookeries may exist for decades, but birds not always
return there in nesting season. Social life allows false ravens to protect themselves
against predators successfully, but also bears the certain inconveniences: neighbours
frequently quarrel and steal nest materials at each other.
These birds are monodins, but pairs are formed more often only to one breeding
season. Pairs are formed at the end of winter (in August or in the beginning
of September); in September rookeries are already occupied by tenants. First
of all birds renew old nests, and then begin egg laying. In clutch it may be
up to 7 eggs, 5 ones are more often. Only female is hatching, but male feeds
her. After young birds become independent (it takes place 1,5-2 months after
egg laying), rookeries quickly become empty. In non-nesting time false ravens
live solitarily or migrate in small flocks.
New Zealand false raven belongs to the number of long-livers: this bird can
live up to 40-45 years.
At Chatham Islands the close species lives – Chatham
false raven (Notocorax chathamensis). It is a little bit larger than its
New Zealand relative (weight up to 3 kg), and in its meal seafood prevails.
Some individuals of this species fly far to the south, to subantarctic islands.
They can nest there, but have not formed a constant steady population. More
often these birds fly back to Chatham before the beginning of winter.
These species of birds were discovered by Simon, the forum member.
Waitoreke
(Waitoreke potamophilus)
Order: Rodents (Rodentia)
Family: Mice and Rats (Muridae)
Habitat: various reservoirs of New Zealand – lakes, streams and rivers.
Picture by Alexey Tatarinov
Waitoreke is a creature equal to black rat in size, but much
more graceful. This rodent is the descendant of black rat introduced to New
Zealand by ancestors of Maori – aboriginals of archipelago. Waitoreke is named
after certain river animal (“otter”) of local legends. In many respects it resembles
this animal which remained a mystery for official science.
The wool of waitoreke is colored grey tone: back and head are dark grey, and
the bottom part of body is ash-grey. The tail of waitoreke is black, flattened,
covered with hairless skin, resembling beaver tail in outlines. Forepaws are
shorter then rear legs and have well advanced fingers. Around of eyes of mammal
there are white “glasses”. Its muzzle resembles muzzle of rat, with well advanced
vibrissa. With the help of vibrissa touches this animal can search for food
even in muddy water. Eyes of waitoreke are large, and ears are small, rounded
and almost unnoticeable in wool.
Waitoreke is skillful fisher, and this fact has leaved a mark on its appearance:
this little mammal has small ears, strong webby hind legs and waterproof fur
like an otter. Secretions of special glands give to waitoreke’s fur necessary
water-repellent properties. Due to greasing the animal gets out of water almost
dry – it needs only to shake some drops of water from itself. Such adaptation
helps this animal to keep heat even at life in cold mountain lakes and streams.
The special valve closes an acoustic duct when animal dives.
This little mammal lives in coastal zone of rivers, streams, lakes of both islands
of New Zealand. Waitoreke prefers to live in woody area, but also settles in
plain areas. It eats various aquatic animals: snails, frogs, aquatic insects
and fishes. Sometimes waitoreke catches nestlings of waterfowl, snatching them
from under water or stealing from nests. Animal catches prey by forepaws and
kills by bite of strong incisors. Waitoreke hunts large fishes in packs.
Waitorekes live in rallied colonies resembling a colony of meerkats. The colony
represents some tens of holes dug near to water edge of reservoir. In each hole
one couple of adult beasts lives. One couple is dominant – their hole is located
in the center of colony, and at lack of forage dominants can take food away
at other animals of a colony. But at danger the dominants attack enemy the first.
When in the morning all animals go to the search of food, some “sentinels” stay
in colony. They notify relatives on danger by loud whistle, and if necessary,
protect cubs actively. The enemy of waitoreke is antipods’
unotter (Xenolutra antipodorum) which lives in a lower reaches of New Zealand
rivers. Herons and large predatory fishes, and also neohanasaki
(Neohanasaki aotearoae), large species of amphibians, may eat adult animals
and cubs.
These animals form pairs to all further life. Courtship period at waitoreke
takes place in spring (October in Southern Hemisphere), and posterity is born
in the beginning of summer. The second litter is born at the end of summer.
In spring litter of this animal numbers up to five cubs though usually it is
less, in summer – no more than three ones. Cubs are born at all couples capable
to breed, and not just at the dominant couple. However in dominant’s litter
cubs are larger, and on the average, the litter numbers one cub more, than at
other couples. Young animals become sexually mature at the age of 6 – 7 months.
At this time young animals leave parental colony and form their own colony,
or join one of existing waitoreke colonies.
This species of mammals was discovered by Simon, the forum member.
Marshland
aotearophis (Aotearophis paludicola)
Order: Squamates (Squamata), suborder Snakes (Serpentes)
Family: New Zealand snakes (Aotearophidae)
Habitat: New Zealand, coasts of freshwater reservoirs.
New Zealand, being separated from the continents many millions years ago, had
unique fauna before human colonization. At the great variety of endemic birds
there was a minute quantity of species of amphibians and mammals here. The specific
variety of reptiles was also low – this class was represented at the islands
only by lizards and tuataras. Crocodiles, tortoises and snakes had never lived
in New Zealand. But in Neocene the situation has cardinally changed. Mammals
and frogs introduced by people have occupied the archipelago, and during millions
years of evolution they changed into new species. Also snakes had occupied New
Zealand. However, as against many other species, these reptiles colonized this
area independently, without the help of people and later after human extinction.
Neocene New Zealand snakes descend from sea kraits (Laticauda), the most primitive
ones among sea snakes that had kept strong connection to land areas. Low specialization
and absence of competitors have permitted them to settle at the islands lack
of snakes earlier. Possible, the colonization of New Zealand by snakes had taken
place after the end of the ice age bordering Holocene and Neocene. Three species
of New Zealand snakes represent two genera of family Aotearophidae close to
elapids. The name of these reptiles is formed as a sum of words “Ao-Tea-Roa”
(Maori name of New Zealand) and “Ophis” (snake).
Evolution of these reptiles is directed to occurrence of land forms having a
diet differing from each other. More primitive forms are closer connected to
aquatic habitats and are ichthyo- and herpethophags to what their high degree
of poisonness is connected. More advanced forms eat warm-blooded animals, and
activity of their poison is much less: in bodies of mammals and birds having
faster metabolism poison has faster effect. In anatomy of even the most specialized
species ancestral features are traced – these are tail slightly compressed from
sides and nostrils shifted to the top part of head.
All aotearophids are egg-laying reptiles. They lay a small number of eggs (usually
less than ten ones) in heaps of vegetative dust or in wet ground. In the convenient
and protected places collective clutches are possible. Parents do not care of
posterity in any way. The first time newly hatched young snakes eat invertebrates,
and then pass to hunt for small vertebrates. The young snakes of aquatic species
eat fish fry and tadpoles.
Large birds and mammals are enemies of New Zealand snakes. Despite of presence
of strong poison, aotearophids almost do not use it for self-defense. They had
inherited peaceful behaviour of ancestors and in case of danger seek safety
in flight, trying to hide in grass or in water.
Marshland aotearophis represents the transitive form between primitive and more
advanced species of family. It is still attached to damp habitats, preferring
to settle near water – in marshes and at the riverbanks. This snake swims perfectly,
however it hunts almost always on land. Marshland aotearophis is specialized
herpetophagus. Lizards and amphibians from among false
salamanders, local group of neotenic tree frog larvae, become its prey more
often. At this species cases of cannibalism are possible. Poison of this snake
is still strong enough, as it hunts cold-blooded animals. The body length of
marshland aotearophis reaches 1.5 meters. Colouring of this animal is dark grey;
on body thin white cross strips stretch.
Two close species of New Zealand snakes display other stages of evolution of
this group.
Forest
aotearophis (Aotearophis sylvestris) is the most evolutionally advanced
New Zealand snake. This reptile inhabits forests of New Zealand. It is almost
not connected to water, but prefers wet places. Representatives of the present
species swim not so good; also they are not capable to climb up trees. In anatomy
of forest aotearophis only few ancestral features are kept: these are tail slightly
compressed from sides and the nostrils located in the top part of head. The
largest individuals reach the length of 2 meters; usual length is about 1.75
meters. This snake has olive color with which numerous thin rings of black color
contrast. Food of forest aotearophis includes small mammals and birds. Poison
of this snake is weakest of all New Zealand snakes, but is strong enough to
kill fast small warm-blooded animal.
Aquatic
aotearophis (Preaotearophis ichthyophagus) is the most primitive species
of family. It keeps many features characteristic for sea snakes – for example,
it is capable to absorb the oxygen dissolved in water by mucous membrane of
mouth. However it already lacks salt-secreting glands characteristic for sea
snakes. Representatives of the present species inhabit the rivers and lakes
at the plains of both large islands of archipelago. Sometimes they may be met
in sea near rivers mouths – these snakes frequently settle along the coast of
islands, therefore islands are inhabited by only one species without subspecies.
Aquatic aotearophises eat mainly fishes, occasionally hunting also larvae of
amphibians and aquatic invertebrates. Egg laying takes place on land. This snake
is about 1 meter long; its tail is strongly compressed from sides and serves
as body of movement in water. Colouring of this reptile is contrast: the whole
body is covered with alternating cross strips of silver-gray and dark brown
colors.
These species of reptiles were discovered by Simon, the forum member.
Rangitahi
(Rangitahi ephemera)
Order: Tailless amphibians (Anura)
Family: Tree frogs (Hylidae)
Habitat: New Zealand, mountain rivers and lakes. Breeding in reservoirs in lower
reaches of the rivers.
Picture by Alexey Tatarinov
In human epoch Australian green tree frog Litoria caerulea
was introduced to New Zealand. It survived during the mass extinction at the
boundary of Holocene and Neocene, and its descendants in due course of evolution
have occupied set of island habitats. One direction of evolution of Litoria
descendants was the prolongation of larval stage of development down to occurrence
of the separate group of neotenic amphibians – New Zealand false salamanders.
It was promoted by poverty if island ichthyofauna. Also among New Zealand species
of tailless amphibians there are some species displaying various stages of transition
to complete neoteny. One of such species is rangitahi – a special kind of frogs
which had a complete redistribution of roles of larval and adult stages of development.
At this species larval stage lasts up to 4-5 years. Rangitahi tadpole lives
in cool mountain streams where feeds on algal films and sedentary larvae of
insects. Its shape is adapted to life in current – rangitahi tadpole has strongly
lengthened body about 30 cm long, scraping mouth looking like a sucker, elastic
lips covered with set of corneous fibers. Tail of tadpole is very large and
muscled – it makes more than 2/3 of the general size of tadpole and is bordered
by skinny fin plica. It not only swimming structure, but also a stock of nutrients
for metamorphosis. Body of tadpole of this frog is brownish with lighter belly
and black longitudinal strip stretching from muzzle across the eye up to the
tip of tail.
Tadpoles grown up to maximal size gather to schools and migrate downstream to
lakes where water is warmed better. Here they undergo very fast metamorphosis
and turn to adult individuals. During the time of metamorphosis rangitahi tadpoles
gather in schools numbering up to several hundreds of individuals. In school
metamorphosis proceeds more speedily due to pheromones secreting in water and
synchronizing this process.
Rangitahi frog has contrast black-and-white color – the bottom part of body,
fingers, toes and spots on sides are white, and back, sides and the top side
of extremities are coal-black. During the metamorphosis at rangitahi frog tail
is resorbing, therefore the adult individual of this kind has length about 10-12
cm. At the same time the rough ripening of reproductive products takes place.
The adult stage at these amphibians serves only for breeding and is simply not
adapted to long existence. It has the reduced tail without the bones, remained
from the stage of tadpole. The intestines at rangitahi frog are reduced in great
degree and nonfunctional, and frequently the cavity of intestines is filled
with connecting tissue. The adult individual of rangitahi lives exclusively
due to stocks of the nutrients saved up during the larval stage. Ephemerity
of adult stage of this species is shown in the name of the species: the word
“rangitahi” in Maori language means something instant, short-term, and existing
not for long.
Courtship ritual at this species is very rough. It begins synchronously and
involves all individuals gathered at the certain area of the coast – it provides
guaranteed success in breeding. Loud calls of this frog resemble sharp abrupt
whistling. When males call in unison, the sound turns out painful for hearing.
In clutch of rangitahi there is up to 300 small eggs surrounded by individual
capsules of slime. The whole clutch is friable and spherical, floating at the
surface of water. Adult individuals do not leave clutch and eggs up to hatching
of tadpoles, and actually to their own death. Frogs protecting eggs are easily
excitable and ready to seize death grip any enemy which has encroached on eggs,
and even their own relative appeared nearby casually.
Incubation lasts for about one week. Hatching of tadpoles is followed by fast
degradation of the organism of adult animal. Stocks of nutrients are already
exhausted to this moment, then fast tissue necrosis follows, and frog perishes
within several days. Tadpoles hatched from eggs hide at the bottom and among
aquatic plants. They gradually migrate to the rivers and reach up to cold streams
in upper reaches, where their feeding and maturing proceed. At the tadpole stage
the settling of this species takes place.
New
Zealand eversmolt (Salmini novazealandiae)
Order: Salmons (Salmoniformes)
Family: Salmons (Salmonidae)
Habitat: mountain rivers of New Zealand.
In human epoch the ichthyofauna of New Zealand differed in certain poverty and
high degree of endemism. This archipelago had separated from continents in Mesozoic
era when typical groups of freshwater fishes had not evolved yet. In Holocene
freshwater fishes of New Zealand were presented by descendants of sea and euryhaline
species. But later the situation had sharply changed. People had introduced
to New Zealand various freshwater fishes descended from other continents, and
had caused irreparable damage to local fauna by this action. After extinction
of mankind newcomer species had quickly developed new habitats, having superseded
the majority of survived native species, and development of ecosystems of archipelago
had proceeded in absolutely another direction.
Climate of New Zealand in Neocene is typical subtropical, and in the south it
is warm-temperate. But the significant part of archipelago is presented by mountain
areas where the cool climate dominates. And at high tops of mountains the most
part of year snow and ice lays. Short cool rivers of islands originate here.
In upper courses of rivers, in crystal-clear and ice-cold water the small fish
keeping by large schools on current is found. From time to time these fishes
jump from water, trying to seize any insect flying above water. It is one of
fishes appeared due to activity of human had missed for millions of years before
epoch of Neocene. This fish is New Zealand eversmolt, dwarf descendant of trout
introduced to New Zealand. Actually it is simply dwarf variety of trout quickly
maturing, keeping in adult condition juvenile attributes, and living not for
long.
New Zealand eversmolt has kept characteristic for trouts propensity to live
in cool and rich in oxygen water. The torpedo-like shape of body with pointed
snout helps this fish to resist to current successfully. Fins of New Zealand
eversmolt are peaked; tail fin is high and crescent. These are attributes of
quickly swimming fish: actually, these fishes all the day struggle with current
only to remain at the same place – near the chosen stone or bush of aquatic
moss. Body length of New Zealand eversmolt is about 12 cm; the female is larger
and approximately 25 % heavier, than male.
Colouring of this fish in details is similar to coloring of its ancestor, brook
trout (the river form of Salmo trutta). Out of spawning season male and female
are coloured similarly: black and red spots on the body form marble pattern
on silvery-green background. At this fish there are large silvery eyes: New
Zealand eversmolt hunts mainly with the help of sight.
The mouth of fish opens widely; on tips of jaws well advanced sharp teeth grow.
Usually this fish keeps in schools in current near water surface. New Zealand
eversmolt eats basically flying insects – dragonflies and May flies. Hunting
fish waits for insects, keeping near stones or leaves of water plants fluttering
in current in order to be not too appreciable at sight from above. When above
surface of water an insect flies, fish catches it right in air in well-aimed
jump. Planning jump, fish instinctively makes the amendment to refraction of
water, and on average each third jump appears successful. Occasionally fish
gathers insects from surface of water and catches aquatic larvae of dragonflies
and May flies between stones.
The courtship season at New Zealand eversmolt begins in spring (in Southern
hemisphere it is October – November) when mountain snows thaw. At this time
males get more saturated colouring: they turn velvety-black with silvery eyes
and red spots on the body. Only on stomach and near anal fin they keep sites
of silvery background colouring. Females, on the contrary, brighten, and their
colouring becomes almost completely silvery with dark grey back and speckled
anal fin. Similarly to salmons of Holocene epoch, New Zealand eversmolt spawns
on current, on sites of bottom covered with fine pebblestone. On spawning places
these fishes gather to schools numbering up to hundred individuals and stay
there within several days. These fishes dig eggs in pebble where clutch is reliably
kept from the majority of predators.
Spawning act of New Zealand eversmolt takes place in the morning. At this time
schools of fishes approach to riverbank, and keep in shallow water. From water
fins of males behaving rather aggressively relatively to each other stick up.
Males combat with each other for place more convenient for spawning, and gradually
the school breaks up to separate groups. The appearing of females at spawning
place results in excitation at males. Their colouring turns brighter, and they
by two or three chase females when they swim near to male groups. Gradually
each female chooses the certain site of bottom, and males surround her. During
the spawning female digs a hole for eggs by lateral movements of stomach and
tail, and after it one or two males throw ground in sides. At the following
attempt female throws up eggs in made furrow, and males immediately fertilize
them. After that fishes dig eggs in ground and do not care of it more. Spawned
individuals are very weak, and at this time various aquatic and ground predators
actively hunt for them. Fishes keep on sites of rivers with slower current,
and sometimes hide in cracks between stones and have a long rest there. The
most part of fishes spawns eggs no more than three times per life.
Eggs develop among pebblestone within approximately three weeks. For this time
part of it perishes from various predators – mainly from worms and larvae of
insects. Fry hatch translucent and helpless, and start to swim at week age.
Up to this moment the significant part of fry perishes, but the number of survived
ones is enough to keep the stable populations of species. The maturity of New
Zealand eversmolt comes at 2-nd year of life, and life expectancy makes up to
5 – 6 years.
Rahirahi
galaxia (Serpogalaxias umbreocollum)
Order: Galaxiiforms (Galaxiiformes)
Family: Galaxiids (Galaxiidae)
Habitat: New Zealand, rivers and lakes, spawning in river estuaries.
Picture by Carlos Pizcueta, colorization by Biolog
Initial picture by Carlos Pizcueta |
Galaxiid fishes are very characteristic for fresh waters of
Southern hemisphere. Before the introducing of various freshwater fishes by
people they represented the dominant group of freshwater fishes of New Zealand.
In Neocene the positions of these fishes in island ecosystems were substantially
lost – descendants of nonnative fishes have occupied the most part of ecological
niches. In New Zealand ichthyofaunal there are no large kinds of galaxiid fishes,
but there is a plenty of smaller kinds. One of them is rahirahi galaxia similar
to loach and occupying a similar ecological niche.
Rahirahi galaxia is a medium-sized species of fishes: body length of an adult
individual is about 8 cm. It is a fish with thin, lengthened (“rahirahi” in
Maori language means “long”) and flexible body, inhabiting benthonic layers
of water. Skin of rahirahi galaxia is naked and slimy; the seized fish secrets
a plenty of slime and tries to escape from predator’s jaws by strong movements
of body. Background colouring is beige with pinkish shade, on body the set of
dark and rounded spots is scattered. In forward part of body large saddle-like
spot covering the area of gill covers, nape and forward part of back is present.
Fins of fish are transparent, but edges of paired fins have narrow black border.
Also the small crescent spot is present in the basis of tail fin. For this species
the variability of colouring depending on time of day is characteristic: at
night the fish becomes pale, white-pink, and dark marks almost vanish.
Fins are short and wide, back and anal fins are shifted to the back part of
body. Tail fin is trapezoid, with small cut in the middle of back edge. This
fish swims in benthonic layers of water and keeps close to shelters - usually
among driftwood and plants in coastal zone. In case of danger it is dug in in
sand or silt dexterously, and at attempt to seize it only buries even deeper.
Rahirahi galaxia eats larvae of insects, catches small tadpoles and digging
crustaceans. For search of prey on the top jaw of this fish in corners of mouth
the pair of wide lobe-like wattles supplied with set of sensitive cells grows.
It is catadromous species of fishes, which life cycle proceeds in part in sea
water. In the beginning of years rahirahi galaxias gather to small schools and
move downstream to river mouths. In estuaries during the high inflow these fishes
spawn eggs at sandy shoalinesses, not reached by tidal waves in the rest of
the time. For this purpose fishes gather in close groups of 10-20 individuals
and bury in sand back parts of their body. At this moment females lay eggs,
and males impregnate them. When fishes get out of sand, eggs appear dug at the
depth of several centimeters. Parents do not care of posterity anymore and return
to the rivers shortly before outflow. Clutch numbers only 100-120 rather large
eggs containing large stock of yolk. Within 28 days, before the next high inflow,
eggs develop, but the significant part of this term is spent by fry in a condition
of rest. During the inflow fry crawl through the thickness of sand to the surface
and swim off to the sea with outflow.
Young fishes will spend in sea for about half-year. They live in thickets of
seaweed in shallow water, and to the beginning of winter migrate to freshened
water of river mouths, move upstream the rivers in spring and settle in habitats
typical for their parents. Sexual maturity comes at the age of 2 years; life
expectancy is up to 8 years.
The idea about the existance of this species is proposed by Carlos Pizcueta
Native
thick-lipped carp (Labiocyprinus indigenus)
Order: Cyprinoid fishes (Cypriniformes)
Family: Cyprinids (Cyprinidae)
Habitat: rivers of New Zealand.
Before the human arrival to New Zealand the freshwater ichthyofauna of this
archipelago was rather poor. People have changed a course of evolution when
have introduced to New Zealand various freshwater fishes from other continents,
and carp – a domestic kind of fishes – among them. After the extinction of mankind
descendants of carp settled widely in freshwater habitats of archipelago, having
formed a lot of life forms – from tiny up to large ones, from swamp dwellers
up to inhabitants of crystal-clear ice-cold water of the mountain rivers.
Thick-lipped carp lives in rivers of New Zealand, preferring moderate current
and clear water. It is especially numerous in foothills where the rivers are
not so fast, but have not grown turbid yet from soil suspension. The length
of native thick-lipped carp reaches 40 cm, though usually these fishes are smaller.
Native thick-lipped carp belongs to omnivorous fishes, and eats algal layers
and sedentary animals living on stones. The mouth of this fish is transformed
to sucker and is shifted downwards. Lower jaw is shorter compared to upper one
and consequently the mouth of fish is constantly open. Thick lips of native
thick-lipped carp are covered with fleecy corneous outgrowths helping scraping
of algal film from stones more effectively. Upper lip is separated to two mobile
halves which can move independently from each other. The frontal edge of muzzle
of this fish is covered with corneous “callouses” helping in ground digging
in searches of forage in case of need. Mouth of fish is surrounded by eight
short wattles – two ones stick forward, two are directed in sides, and four
are turned back. Wattles are covered with various receptors, including taste
and tactile ones. They provide fish with adequate information on world around.
Eyes of native thick-lipped carp are directed upwards and in sides.
Thick-lipped carp has a convergent similarity to Labeo and other fishes living
in fast flowing water. Body of this fish is triangular in cross-section, with
wide flat stomach. Back of fish colored brown, sides are greenish, and stomach
and the bottom side of head are white. Fins of fish are grey with dark spots
in the basis. Out of spawning season male and female at this fish are practically
indiscernible in colouring. Fish spends the most part of time at the bottom;
therefore the swimming bladder at native thick-lipped carp is reduced and represents
a simple tissue taenia filled with fat. Caudal peduncle is short; tail is strong,
equipped with wide two-lobed fin. On the top blade of male’s tail fin the long
“thread” is advanced – some extended and flexible fin rays connected with membrane.
“Thread” has a pattern of cross black strips.
All fishes living at the current face with the common problem, the necessity
to keep on the same place. Thick-lipped carp has left this difficulty, having
developed “clawed” fins: tips of thick forward rays of pectoral and abdominal
fins stick out from edges of fin membrane and are slightly bent downwards. They
allow fish clinging against smooth stones and to keep firmly even in strong
current. Usually each fish has some favourite places of rest – small holes in
river bottom, where it is almost not necessary to cling by fins.
In way of life native thick-lipped carp represents solitary territorial fish.
Each individual occupies a territory of about twenty square meters, extended
along the watercourse. At the areas poor in food territories of these fishes
can be even larger. Borders of territory are well-known to each individual,
and it is ready to die in the last ditch, protecting the possession against
congeners.
In spawning season male gets very bright colouring – its body becomes emerald-green
with iridescent shine, and fins get red colouring. “Thread” on its tail fin
becomes more contrast in colouring and well appreciable. Male ready to spawning
begins “singing” – with the help of pharyngeal teeth it utters loud clicks.
This way it warns other males about its rights to this territory and involves
females to the place of spawning.
These fishes spawn in pair and lay eggs in simple hole dug out in the river
bottom near to riverbank. After spawning male fills hole up and protects the
territory, where the nest is located, against congeners and even against other
fishes of rather large size. It attacks newcomers aggressively, striking them
impacts by strong snout. But at the same time in fact it does not pay attention
to small animals; therefore aquatic invertebrates – insects and freshwater crabs
– cause great damage to posterity of this fish.
Young thick-lipped carps since the first days of life are given to themselves.
Death rate among young fishes of this species is very great, and at times only
1-2% of the number of the brood survives until the second year of life. But
life expectancy of these fishes may reach 100 years and more. From 4-years age
young native thick-lipped carps can take part in spawning, and to 8-9 years
they reach the size characteristic for adult fish of this species.
Ika-taikaha
(Perca taikaha)
Order: Percoid fishes (Perciformes)
Family: Perches (Percidae)
Habitat: rivers and lakes of New Zealand.
Picture by FanboyPhilosopher
Human epoch has left a significant mark in ichthyofauna of
New Zealand. The intentional introduction of various kinds of European fishes
has resulted in extinction or sharp reduction of number of native species of
fishes. But introduced species have shown perfect adaptive opportunities, and
New Zealand ichthyofauna of Neocene epoch is submitted mainly by their descendants.
Among them one of the main predators is ‘ika-taikaha, very large kind of perches,
the descendant of the introduced European perch (Perca fluviatilis). Translated
from Maori language, the word “taikaha” means “furious”, and this name is attributed
to fish occupying the top of food pyramid in rivers and lakes of archipelago.
‘Ika-taikaha in fact is only a huge version of ancestral form. Because of absence
of competition it has changed a little, having only increased in size. Body
length of adult individual is about 100-120 cm. Fish has deep body, rising like
a “hump” right after head and covered with characteristic rough ctenoid scales.
Adult fishes prefer to live in deep water far from land and occupy mainly the
central part of lake or river channel. Due to it body colouring of adult individual
is bluish with white stomach and dark grey vertical strips and back. Large eyes
have yellow color. Spiny back fin includes 15-16 strong prickles. At adult fishes
soft back fin has black base and pinkish border. Tail fin is two-lobed.
Mouth may be widely opened and pushed forward a little; it is supplied with
pointed teeth. ‘Ika-taikaha is a predator and eats any animals it is able to
catch and to swallow entirely – fishes, frogs, false salamanders. Young fish
eats mainly insect larvae and fish fry. Adult ‘ika-taikaha frequently attacks
chicks of waterfowl, mountain penguins and also waitoreke – local aquatic rodent.
Spawning occurs at the end of spring in shallow water – more often near lake
shores or in shallow backwaters with slow current. In courtship dress colouring
of male becomes azure-blue, and strips and back get velvety-black colouring.
Head is colored black, and yellow eyes look especially impressively against
this background. Soft back fin and anal fin of male in courtship dress get orange-red
colouring. During the spawning pair of fishes splashes noisily at the surface
of water, and male chases female and bites its caudal peduncle. Clutch of this
species represents the mucous tape strongly inflating in water and containing
some tens of thousands of eggs. Fishes leave clutch to the mercy of fate. Egg
development lasts about two weeks. For ‘ika-taikaha cannibalism is characteristic
at all stages of development. Sexual maturity comes at the age of 5-6 years,
life expectancy makes more than 60 years. Intensive growth proceeds until reaching
the age of 10 years, when fish reaches the length of about 60 cm.
‘Ika-kaihopu
(Kaihopu esocinus)
Order: Toothcarps (Cyprinodontiformes)
Family: Live-bearers (Poeciliidae)
Habitat: rivers and lakes of New Zealand (Southern Island).
From the point of view of biogeography human epoch was an epoch of blurring
of borders between biogeographical realms – at this time mass introduction of
representatives of various groups of live organisms to habitats unusual for
them had taken place. Among fishes such immigrants represented mainly food fishes,
but one species – mosquitofish (Gambusia affinis) – had been settled to various
continents and islands for struggle against larvae of blood-sucking insects.
Gambusia had survived the time of human extinction and its descendants live
in many places where it had been introduced. In New Zealand the competition
to local fish species was insignificant, and one descendant of Gambusia has
turned to active predator.
‘Ika-kaihopu is a large viviparous fish of fresh waters of New Zealand. Its
length reaches 30-40 cm (female is larger and heavier than male). The head of
fish is lengthened, with extended jaws and wide mouth which opens and extends
forward like a tube, permitting fish to suck prey in. Body shape allows ‘ika-kaihopu
to swim under the surface of water – back and head of fish form almost straight
line. Eyes of fish are large, slightly shifted above the top edge of head. Back
and anal fins are shifted back; caudal peduncle is short and thick, with fanlike
tail fin. ‘Ika-kaihopu prefers to swim slowly near the water surface, making
fast rushes only to catch prey. Stomach of fish is strongly convex and may stretch
considerably. On male’s anal fin forward beams form gonopodium – the mobile
copulating structure.
Colouring of back of ‘ika-kaihopu is green with brown “marble” pattern stretching
to sides. Background colouring of sides is yellowish-green, stomach is white.
Male’s colouring is more sated, than female’s, and the marble pattern is present
only on the top part of back. Fins of fish are transparent, only in the basis
of back fin there is a brown spot, and at male there are also brown speckles
on anal fin.
It is exclusively predatory fish that is reflected in its name: in Maori language
“kaihopu” means “hunter”. Small fishes, frogs and false salamander larvae, and
also large aquatic insects form a diet of this species.
Breeding of ‘ika-kaihopu lasts for all year, though in winter it proceeds less
intensively. Approximately once in 2-3 weeks female gives rise to several large
juveniles of brownish colouring with silvery sides. Length of young individual
at birth is about 3 cm. In winter the interval between delivery acts is increased
and the number of young fishes is reduced up to 1-2 at once, but winter-born
fry has length up to 5 cm at birth. Male chases the female ready to breeding,
trying to keep as cautiously, as possible – female is capable to attack it,
and even to eat smaller male. If female does not display aggression, male nestles
against its side, quickly impregnates it and swims out immediately. Young fish
reaches sexual maturity at the age of 1 year, and life expectancy makes about
10 years.
‘Ika-‘iti,
leaf-mimic live-bearer (Paragambusia foliomima)
Order: Toothcarps (Cyprinodontiformes)
Family: Live-bearers (Poeciliidae)
Habitat: rivers and lakes of New Zealand (Southern Island).
In historical time people had introduced some species of live-bearing fishes
to New Zealand, but in due course of evolution descendants of Gambusia appeared
the champions on speciation; these ones formed a significant number of species
differing in shape and ecology in reservoirs of archipelago. Some species have
turned to large predators, and others have remained smaller creatures.
One of small species of live-bearing fishes lives in lakes of Southern island
– it is ‘ika-‘iti, or leaf-mimic live-bearer. It is a small fish about 4 cm
long, but usually even smaller (the word ‘iti in Maori language means “small”),
eating insects and their larvae. It has deep body compressed from sides, leathery
keel on the bottom side of body from throat up to anus, short head with small
eyes and wide mouth capable to extend like a tube. Fins of this species are
short, rounded and transparent.
Colouring of ‘ika-‘iti is very original. In it two contrast colors are combined:
light green background and dark, blackish-brown color with reddish blotches.
Dark blotches on body form a pattern with irregular edges, resembling strongly
destroyed rotten plant leaf, hence the another name of this species. In case
of danger ‘ika-‘iti freezes motionlessly and floats near the surface of water,
imitating dead leaf. Thus one fin hidden from predator by body of fish continues
movement and fish swims away slowly. In it the convergent similarity of this
fish to some representatives of Nandidae family is shown. But, while Nandidae
are predators, leaf-mimic live-bearer needs such masking for protection. If
the attack proceeds, fish seeks safety in flight. Thus it alternates the directions
of movement sharply and due to narrow body squeezes easily into thickets of
aquatic plants.
Habitats of this species include rivers with slow current, lakes overgrown with
plants and coastal zone of large reservoirs. ‘Ika-‘iti swims rather slowly and
is able only to short rushes during feeding. The main food of this species includes
insect larvae and other small invertebrates, including snails newly hatched
from eggs. ‘Ika-‘iti keeps more often in thickets of coastal plants and under
groups of floating plants.
Male differs from female in smaller size, less expressed belly keel and large
gonopodium. In 2 weeks after pairing female gives rise up to 20 tiny young fishes,
which hide in thickets of floating plants. The subsequent litters differ in
lesser number of fry. For this kind cannibalism is characteristic.