Common Cuckoo

The common cuckoo is 32 to 34cm long from bill to tail, with a wingspan of 55 to 60cm. It has a greyish, slender body and a long tail, and in flight looks like a sparrowhawk. During the breeding season it often settles on an open perch with drooped wings and a raised tail. A rufous colour form occurs occasionally in adult females and more often in juveniles (Wikipedia, general species account).

It is a brood parasite, laying its eggs in the nests of other birds, particularly dunnocks, meadow pipits and reed warblers, and the egg matches the host's. The adult mimics a sparrowhawk, which gives the female time to lay without being attacked. The male's song is a two-note goo-ko, usually given from an open perch. The sources opened give nothing specific to Bhutan.