Common Hawk-Cuckoo

The common hawk-cuckoo, popularly the brainfever bird, is a pigeon-sized cuckoo about 34cm long, ashy grey above and whitish below with brown cross-barring, a broadly barred tail and a distinctive yellow eye-ring. The sexes are alike, though males tend to be larger. It closely resembles the shikra, even in its flap-and-glide flight, and small birds and squirrels may raise the alarm as if it were a hawk. The large hawk-cuckoo is similar but has dark streaks on the throat and breast (Wikipedia, general species account).

It is a brood parasite that lays its eggs mainly in babblers' nests. In summer, before the monsoon, males give loud, repeated three-note calls rendered as brain-fever, rising to a crescendo and ending abruptly, sometimes through the day and well into the night. It is arboreal and rarely comes to the ground (Wikipedia, general species account).