Asian Koel

The Asian Koel is a large, long-tailed member of the cuckoo family, far better known by its loud, insistent voice than by sight, since it often stays hidden in dense foliage. The male is glossy blue-black overall with striking crimson-red eyes and a pale greenish-grey bill, while the female is dramatically different: dark brown above liberally spotted with white, and barred and streaked below, providing effective camouflage.

Like many cuckoos, the Asian Koel is a brood parasite, laying its eggs in the nests of crows, which then unwittingly raise the koel chicks, often at the expense of their own young. The male's persistent, rising "ko-el" call, repeated with increasing intensity, is one of the most recognizable sounds of the South Asian pre-monsoon season.

Key field marks

• Male: entirely glossy blue-black plumage, bright red eyes, pale bill
• Female: dark brown above with white spots, buff below with dark streaking and barring
• Long tail; slim, elongated cuckoo shape
• Usually detected by voice before being seen, staying within leafy canopy

Similar species

Male Asian Koels can superficially suggest a crow at a glance, but are slimmer, longer-tailed, and have red (not dark) eyes. The Greater Coucal is larger, has chestnut wings and a heavier build, and does not share the koel's parasitic breeding or loud repeated call.

Asian Koels range across the Indian subcontinent, Sri Lanka, Bangladesh, and through Southeast Asia into southern China, Indonesia, and parts of Australia. They favor wooded gardens, open forest, groves, and urban areas with sufficient tree cover, often near crow populations that serve as their primary host species.

Some populations are resident while others show partial migratory movements, with numbers increasing in many areas during the breeding season.

Voice

The male's far-carrying, repeated "ko-EL, ko-EL" call rises in pitch and intensity and is a signature sound of the pre-monsoon and summer months across South Asia; females give a sharp, chattering "kik-kik-kik" call.

Feeding

Asian Koels feed largely on fruit and berries, especially figs, supplemented with insects and caterpillars, distinguishing their diet from the more insectivorous habits of many other cuckoos.

Nesting and breeding

The species is an obligate brood parasite, with females stealthily laying eggs in the nests of House Crows and Jungle Crows, sometimes after a pair of koels distracts the host crows. The koel chick often hatches and grows quickly, being raised entirely by the unwitting crow foster parents.