Visually indistinguishable from Oriental Cuckoo. Adult male is gray above with a black-and-white-barred belly and a dark gray tail; females usually look similar, but some (known as hepatic morph birds) have cinnamon-brown upperparts with black barring throughout. Intermediate in size between Common and Lesser Cuckoos; distinguished from both species by buffy (not white) under-tail feathers and from Lesser Cuckoos by yellow iris. Song is a series of five notes, with the leading note being sharper and more distinct than the four that follow; compare with Oriental Cuckoo’s series of mellow paired notes. Breeds in a wide range of different lowland and hill forests; also more open habitats outside of breeding season.