Common Cuckoo - Kүkuк
Cuckoo - a bird of the cuckoo family.
Externally resembles a small hawk. The total length reaches 32-34 cm, wingspan 55-65 cm, weight up to 80-190 g. An adult male has the entire upper side of its body, including the head, colored dark gray. The throat and crop are also gray, but of a lighter ash shade. The belly is white, with dark transverse stripes. The tail feathers have white tips and spots along the shafts.
It lives in light forests and gardens. It is beneficial, feeding on insects and their larvae. It arrives in the second half of April. It usually stays alone, less often in pairs. It does not build nests.
For most of the year, the cuckoo leads a secretive, silent lifestyle. Only in spring and the first half of summer do females and especially males become noticeable and noisy, attracting attention to themselves. The most famous is the male's courtship song — a loud measured call "cu-coo...cu-coo...".
The common cuckoo is one of the most advanced brood parasites, laying its eggs in the nests of other birds. About 150 species of passerine birds serve as foster parents for its chicks. Female common cuckoos are divided into so-called ecological races, also known as lines. Each of these races lays eggs of a specific coloration and seeks to place them in the nests of those birds that lay eggs of a similar color and size.
The cuckoo searches for suitable nests throughout the time its main foster parents are breeding. The most favorable option for the cuckoo is to find a pair during the nest-building phase and determine the location of the nest based on their behavior. This also allows it to lay an egg as one of the first, which guarantees earlier development of the chick. The female can sit motionless on a perch for hours, watching nesting birds, and reacts weakly even in the event of an attack. Once it spots a suitable place, the bird flies away and returns to the same spot when the formed egg is ready to be laid.
In the nest of its victim, the cuckoo usually spends no more than 10-16 seconds, during which time it manages not only to lay its own egg but also to take one of the host's eggs (that is, to make a substitution). The latter is immediately swallowed or carried away in its beak.
Typically, during the breeding season, the cuckoo lays no more than 10 eggs, each time in the nest of a new host.
It happens that two or even more parasite eggs belonging to different females end up in one nest.
The size of the eggs is (20-25)x(15-19) mm. The incubation period for the common cuckoo is 11.5-12.5 days. If the egg was laid at the beginning of incubation, the chick hatches a few days earlier than its nestmates, and this circumstance gives it a significant advantage in the struggle for survival.
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