Juvenile Common Hawk-Cuckoos

 The Common Hawk-Cuckoo (hierococcyx varius), is a fascinating species with a unique life history as a brood parasite. This means its young are raised not by their biological parents, but by unsuspecting foster parents.

Juvenile Common Hawk-Cuckoos look quite different from the adult birds, and interestingly, they mimic the appearance of immature Shikra (a small bird of prey). This mimicry likely helps them avoid being mobbed by the small birds whose nests they parasitise, allowing them to remain in the host's territory. They are generally browner on the upper-parts than the ashy-grey adults. Their whitish underparts are heavily streaked with brown, particularly on the breast, and they may have large brown chevron marks on the belly. This streaking gives them a raptor-like appearance. Juveniles often have a pale or orange-tinged bill and a less distinct yellow eye-ring compared to the bright yellow of adults. The tail is broadly barred, similar to the adult. The juvenile Common Hawk-Cuckoo's behaviour is entirely shaped by its parasitic nature.

After hatching, the cuckoo chick typically evicts the eggs or young of its host (usually Jungle Babblers or other babbler species) from the nest. This ensures it receives all of the foster parents' attention and food. The cuckoo chick grows rapidly and has an insatiable appetite, demanding constant feeding from its foster parents.