Coucous & Co. - Dans le nid d'un autre [Documentaire animalier 2018]

Everyone knows his song. But almost no one knows him. The grey cuckoo cultivates discretion, and for a reason. Unseen, he lays his eggs in the nest of other birds, so as not to have to cover them. No wonder he has a flock of enemies. He leaves the care of raising his young to frivolous birds. But the most amazing thing is that the supercultivation is not discovered. Even intelligent birds like the hawks accept without hesitation the presence of a cuckoo in their nest. By what mystery? Recent observations reveal the clever stratagems used by cuckoos and others. A small pond area in northern Germany, bordered by trees and rosebushes. In the spring, the bird population is captured by reproduction. Raising a cuckoo is not a sinecure. No more than building a nest. Especially when you fly above your head. But the hawks do not let themselves be disconcentrated. Once in the world, the birds must be protected, fed, cared for, etc. If he could avoid this corvée. The cuckoo does not worry about building a nest or raising his offspring. No, he parasitizes the nests of other birds. He traveled 5,000 kilometers from Africa to return in the spring to the rosebush where he grew up. A humid area full of insects. He did not come to hunt them. But he knows that where there are insects, there are insectivorous birds. They are the ones who interest him. The rosebush grunt investigates him and confronts him courageously. The cuckoo does not formalize. It is not the grunt that interests him. But birds that look like his adoptive parents. Rousserolles and farvates. His goal is to make an exchange of them. Here, it is too early. The rousserolles are still building their nest. But in this one, the female is already hatching. The ideal timing to fulfill his deal. The rousserolles know how to recognize their eggs. They are gray and fluffy. She would immediately spot an intruder. How to do? The female cuckoo is waiting for the moment when the two adults will leave the nest. Now. She removes an egg and lays two eggs instead. It's done. No witnesses. When they return, the rousserolles will see that there are still four eggs hatched. There are slightly larger than the others. And then? Slight hesitation. The shadow of a doubt, perhaps. Finally, the subterfuge has succeeded. The cuckoo egg has gone unnoticed. Each female cuckoo is specialized in a single species. The pig, squirrel, squirrel, for example. The eggs of the cuckoo always look like those of the other. Finally, more or less. Thus, when the victims are red with white fronds, the cuckoos lay turquoise eggs. The others only see fire. And when the mystification is a bit coarse, like here. This is a nest of rousserolles verderolles. So far, the cuckoo egg has not disturbed its owners. The rousserolles verderolles, which look like their cousins and pharvates, do not nest in the spruce stems, but much lower, in the burrows. They stay in the nest. This is when something unexpected happens. Hearing the cuckoo's cry, the rousserolle seems to come out of its torpor and its gills. You, the cuckoo, you have nothing to do here. The little cuckoo has dismantled the door. But its mistrust is awakened, and it inspects its nest immediately. Indeed, an egg, a little bigger than the others, seems suspicious to it. How to neutralize it? On the top floor, among the rousserolles and pharvates, no one suspects the presence of an impostor in the nest. For its part, the rousserolle verderolle rushes to break the undesirable egg. The shell of the cuckoo's eggs is very thick, but it ends up breaking. What follows may surprise the most alert ornithologists. The rousserolle devours the egg. What should have become a cuckoo ends up as a shell-egg at the bottom of its nest. The life of cuckoos is not a long, peaceful river. The indelicate occupant has been unmasked, then eliminated. The rousserolle verderolle is very gifted at recognizing eggs that are not its own. The cuckoo often plays hide-and-seek with it. Now, everything is back in order in its nest. Who loses, who wins. On one hand, the parasitic birds improve the control of their eggs. On the other, the cuckoo is forced to perfect the mimicry of its own. The rousserolle verderolle is too naive. Unable to examine its eggs with all the rigor required, it welcomes a bomb in its nest late. The cry of the grey cuckoo is far from unanimous, but it has a distant cousin who is very appreciated and even venerated. It lives in Africa, in the forested savannah of Zambia. The birds here seem to like bright colors. Except for one, so discreet that it is almost invisible in the branches. The great indicator does not want to be seen, because, like the cuckoo, it lays its eggs in the nest of another. But for the moment, it is hungry. And it would eat a lot of bee wax, its favorite food. Problem, we have to pass the gate of the guardians at the entrance of the road. The indicator needs reinforcement. And it knows where to find it. It seeks the help of men like Lazaro. It makes some meadows, moves forward a little, and waits for Lazaro to join it. It continues to drive a few hundred meters. Goal achieved. The smoke serves to fatten the bees. Lazaro can then harvest the honeycombs. And all this thanks to the bird pilot. No wonder men love it. Lazaro operates with his bare hands, at a dizzying height. And he will be left for a dozen stings. The man harvests the honey. And the bird? It receives its reward. It is the only bird capable of digesting bee wax. This partner is very keen on equity. If it did not touch its share, it would quickly put an end to their arrangement. A mutual benefit relationship. But in the fall, at the time of the climb, the indicator reveals its dark side. Everywhere in the savannah, we scratch the ground and dig underground nests, connected to the outside by an access gallery. The builders and tenants of these terriers are the tiny guinea pigs. The two parents have briefly left their nests unsupervised to go and feed themselves. From their perch, they watch out for insects. They skillfully intercept them. Before returning underground, they sneak along the path. The nest is plunged into darkness. They cannot see the eggs, only touch them. The lighting is due only to the infrared camera. A priori, the nest is safe. But there it is. There is the great indicator, and its ferocious drawings. It spies on the terriers, and no longer knows where to look, since the entire ground of the savannah is a real grotto. The guinea pigs come in and out without knowing that they are spied on. The female indicator is in a hurry to lay her eggs. The nest of the guinea pig, with its four eggs, would do just fine. It is momentarily unsupervised. This is the moment the indicator was waiting for. The parents are out, the path is clear. Last check. You have to act quickly. The indicator has to flatten to penetrate inside. A fifth egg is added in a few seconds. The guinea pigs may have a bad surprise. Back in Germany, on the territory of the cuckoo. At first sight, not much has changed. The aquatic grass is a little denser, the rosebush more fertile, the life of the family is in full swing. But a drama is brewing. After 12 days of incubation, a first chick comes to the world, in the nest of the guinea pig. The female cannot know that this chick is not hers, nor that it will eat like four. It is not a coincidence that it hatched two days earlier than the others. But for now, it is defenseless and hungry. Instinctively, its adoptive parents feed it. The little one is still naked and blind, but it knows what it wants. Living insects. Adults give it in the beak everything they find. Cockroaches, flies, dragonflies, coleopteres. The goal is for the bird to grow up and gain strength quickly. Which it will do more than once. The female feels such a stir in her belly that she stops cooing. Baby cuckoo is slowly getting rid of the other eggs. He immediately regains his momentum. Rebellious, under the eyes of the female who watches the scene without reacting. The terrible chick throws its brothers and sisters overboard. Two less competitors. Cockroaches and cockroaches understand nothing of what is happening and are fed to feed the little one who is moaning with a deplorable throat. It only weighs three grams. Where will it find the strength to expel the third egg out of the nest? It is blind and has only wings. Explanation. He has a hypersensitive zone on his back. And everything that comes into contact with the skin in this place causes an unbearable pain and is immediately ejected. Baby cuckoo, make a carnage. And it won't stop there. In the wooded savannah of Zambia, the indicator laid its egg at the foot of the guinea pigs. So far, these manigances have gone unnoticed. For days, the guinea pigs have been taking care of their eggs. And for this fifth egg, which they had not seen in the dark. They do their parental duty, heat the eggs and return them. A first chick comes out of its shell. Here too, with a few days in advance. It is the baby indicator. Its croaking beak reminds that of raptors. Which leaves nothing to be desired. The parents act as if nothing had happened. A few days later, another chick hatches. Without strength, blind and without a croaking beak. Instinctively, it seeks refuge with its big brother. Fatal error. It gets lacerated. And ends up succumbing to its wounds. All this, in the total indifference of the parents. They will thus lose all their young. Without seeming to be moved. The usurper will remain alone on board. And alone to feed. It has made a clear place thanks to the small membrane hooks on its beak. Two weeks later, the hook has disappeared. It is no longer useful. When the indicator leaves the darkness of the terrier. It will become a sunny and friendly bird. Who will seek contact with humans. To guide them to the wild bees. It knows where to find them, but can not access it. Men can access it, but do not know where to find them. Who would believe that this bird so useful to slaughter all his brotherhood. In Germany, spring is well settled. The little cuckoo has grown. A week and a half earlier, he made the void in the nest. Now, he fills it entirely. He is a unique child. And the only mouth to feed. But he has an insatiable appetite. How to get more and more? Again, he shows a very sharp tactical sense. He is not content to be noisy. He imitates the cries of a whole nest. The parents, Bernie, bring even more food. The cuckoo is definitely very strong to deceive his world. The size of the chick should not put the chip in the ears of the roosters? If they know how to recognize their eggs from the first nest. Why do not they know what their chicks look like? Because it would be fatal to all species parasitized by the cuckoo. Indeed, all their life, they would consider their own young as strangers, would abandon them and let them starve to death. It is even better to raise an illegitimate chick, whatever its appearance. Parasitic birds have become masters in the art of deceiving, manipulating, deceiving. But they sometimes make mistakes. Including the cunning indicator of the savannah. If the female lays her egg in the wrong place at the wrong time, nothing goes right. This couple of cuckoos has two young in full health. The remaining eggs seem empty or dead. A fairly frequent case. The young have trouble feeding in the dark. They pinch the parental beak and sometimes the mouth remains stuck. The parents are patient and careful to make their life easier. The indicator seems to have spared this nest. But we do not rejoice too quickly. The days go by and at night other species reign. The wind howls with such art. It is also at night that the true owners of these terriers are shown. The porcupines are only sub-inhabitants. The true master of the places is him, the orycterops. It is endowed with powerful claws, essential to dig its underground bunkers. The sun rises on a day that will be rich in rebound. The two little guinea pigs have grown up and manage to take their meal conveniently. Quickly, we go out to go to the supply. Eventually, let's go back. It looks like the young are out of business. But there is this egg, which is neither empty nor dead. Another porcupine breaks the shell. It can not be a killer chick. It would have been closed before the others. But we said, even the indicators can be wrong. The egg was laid much too late. But it is indeed a killer chick. The beak, equipped with a hook, leaves no doubt about it. Barely born, these killer instincts take over. He wildly attacks his adoptive brothers and sisters. Which, fortunately, are big enough to defend themselves. Suddenly, they turn against him. The indicator has no chance. The revenge of the guinea pigs has nothing to envy to the barbarism of their predator. Are the cuckoo birds all monsters and murderers? Not necessarily. In Spain, at the foot of the Pyrenees, a species of cuckoo concluded a non-aggression pact with its adoptive parents. On one side, the black corneas. On the other, the gray cuckoo. It is a little bigger than our gray cuckoo. Its plumage is fuzzy, and its cry is different. Originally from Africa, it migrates to Spain in the spring, as soon as it is sure to find enough food there. It consumes, in particular, bread processing caterpillars. But the first thing it does is to look for a partner to mate. The offspring of the couple will be raised by cranes. Birds known for their strength and intelligence, who rarely leave their nest. Does the cuckoo really make the right choice? It will have to wait at least until the nest is unguarded. It will not fight arm and galley with the cranes. It is aware of everything that could make it save time. A young one is just passing by. Will the cranes fly away to chase it? More botherers. Ornithologists came to inspect the nests. Once the ladder is placed against the trunk, the cranes become wary and go to shelter. The cuckoo takes advantage of the low tide. No question of dragging. Once the egg is laid, it folds back. The cuckoo has taken advantage of the diversion offered by the ornithologists. Unlike its cousin, the grey cuckoo, its cranes will not be guilty of either brutal expulsion or murder. To be convinced of its good intentions, let's observe a neighboring nest. The cranes have hatched and, surprise, the little grey cuckoo rests peacefully with its brothers and sisters. It is fed at the same time as them. It is the one in the foreground with a clear belly. The cleaning service is included. Let's go for the second service. On the menu, a chicken carcass. The black cranes are carotid birds. The cranes fill their gozzi to the brim. It will then be served to its cubs with the regurgitated food. During meals, the cuckoo is not left out. Its incessant chirping pushes the parents to double their efforts. Statistics show that the presence of a grey cuckoo in a nest increases its chances of success. A cuckoo that brings advantages to its parent cranes. Who would have thought? Be careful not to overdo it. A raw egg for breakfast. The grey cuckoo has swallowed the yolk but continues to cry. The male is so under pressure that he forgets that he has dejections in his beak. And he pours them into the beak of the cuckoo. In Germany, baby cuckoo has crossed a new cape. With new challenges to face for him and his parents. He has to hold on to his legs. The nest of the roe deer has become too narrow. And he is about to fall into the water. Even feeding him becomes more complicated. And above all, acrobatic. It may be better with momentum. In stationary flight, in a humming way. Attempt to land on its back. Success. The cuckoo will never see its real parents. But it is to better recognize the appearance and the cry of its adoptive parents. He knows their habitat. He knows that he is weaving their nest between half-heighted roe deer stems. He will become a specialist of the roe deer and cuckoo. And it will be vital for his survival. He will spend the fall and winter in Africa. And when he returns in spring, he will return to the roe deer he saw being born. Even if the sight is not extraordinary, he knows that it is the territory of the ferocious roe deer. They have spotted the cuckoo for a long time and are trying to keep him at a distance with loud cries. Without great success. If he is there, it is to use it as a nurse. Why does the cuckoo not simply build its own nest? It was the case millions of years ago. Today, the male continues to collect materials for the female, like a reminiscence of his old days. But even before, it happened that the cuckoo landed in the nest of another, as many birds did. This practice succeeded him so well that he adopted it definitively. It may be because of the well-willed caterpillars. Adults eat them without problem. But it is likely that the varied diet of adoptive parents improves the growth of the chicks. Anyway, the cuckoo has lost the ability to raise its own offspring. So yes, the cuckoo cheats, cheats, sometimes kills, but he has no choice. His song announces the arrival of spring. But also that of a bird, which for better and for worse, is forced to find parents to replace his children.