The Asian Koel is a large and long-tailed cuckoo measuring 39-46 cm (15-18 in). The male is glossy bluish-black, with a pale greenish grey bill and the iris is crimson. The female is brownish on the crown and has rufous streaks on the head.
It is recognized as an important seed disperser in Asian forests due to its large gape, which allows the Koel to swallow diverse and large-sized fruits.
A likely resident, its distinctive “Koo-Ooo” call is often heard around the USRC.