Although the habit of cuckoos of laying eggs in the nests of other birds may seem alienating or even disgusting to humans, the reason for this is the attempt to produce offspring with as little energy consumption as possible, notes Heiko Kruusi, an education specialist wildlife at Tallinn Zoo.
According to Kruus, about 50 to 60 of the world’s 150 crayfish species lay their eggs in the nests of other birds. “probably some sort of evolutionary wisdom has accumulated there, which allows them to get by more energy efficiently, so to speak. Many things in the world can actually be reduced to simple laws of nature. One of them is always linked to energy. Building a nest, maintaining it, then hatching and caring for the chicks are very energetic things,” said the program specialist “Hommik Anuga”.
So, in his opinion, the fact that this year the Ornithological Society received the bird from the cuckoo should not be looked at sideways. Bird of the Year is not so much an honorific as we have a national bird, the swallow, in high honour. The Ornithological Society wants to draw people’s attention to a particular bird or group of birds and put it in the spotlight for a year. One of the reasons is that little is known about him,” Kruusi underlined.
While probably every person living in Estonia can recognize, for example, a falling cuckoo, it is not known exactly where cuckoos winter in Estonia. Therefore this year it is planned to attach GPS transmitters to five Estonian cuckoos to clarify the issue. “In general, it is known about European cuckoos that they could go south to the Sahara desert, and they can even go there, where most of the world’s cuckoos meet,” the specialist said.
Much more is also known about nest parasitism, which cuckoos employ to procure their offspring. For example, a female cuckoo can lay 20 eggs, some even report 50 eggs during the breeding season. “A characteristic feature of her is that she can keep the egg there for about 24 hours, passing exactly the right moment when it is appropriate to lay it. She broods a little, which is useful for the cuckoo, so that the child is born sooner.” in the litter box,” Kruusi said.
Naturalists have also recorded cases when a raccoon scares birds with its appearance from its woven nest to lay its egg in it. In these cases, sometimes the male cuckoo also lends a hand. Kruusi added that cuckoo eggs are relatively small considering the size of the bird. “It lays its eggs even in a relatively small bird’s nest such as a pine cone,” the specialist pointed out.
However, during the course of evolution, numerous species of birds have developed that are capable of recognizing cuckoo eggs in their nests. Conditionally, the term close relatives is used for them. 10-15 of these species live in Estonia. “If they see something suspicious, in many cases they use their own tactics to keep this cuckoo from hatching,” Kruusi said. They may push the egg off the nest, leave the nest behind, or build a complete nest layer on top of the cuckoo egg.
Despite the species’ living habits, Heiko Kruusi found that cuckoos are relatively beautiful. “Look how beautiful his yellow eyes are, for example. They really shine,” the specialist said. At the same time, it was argued that a certain fraud is also inherent in the appearance of the bird. So, with its yellow eyes, banded belly, long tail and flying silhouette, it resembles a golden eagle.
2024-01-07 08:45:00
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