The koel bird is also called nightingale in India because of the melodious call of the Koel. The Asian Koel is a large-long tailed, cuckoo, which is forty-five centimeters in length. The male is bluish black in colour with a pale green bill, rich red eyes and grey legs and feet. The female has a brownish upper part and the lower parts are whitish in colour. The females have an olive or green beak and red eyes. It is a brood parasite, which lays its single egg in the nests of a variety of birds, which includes the Jungle Crow and the House Crow.
Koels are very vocal and make different types of calls. The Asian Koel is omnivorous, which consumes a variety of insects, caterpillars, eggs and small vertebrates. The adult Koel largely consumes fruits. It occasionally consumes eggs of small birds.