
Photo: Tisha Mukherjee · CC BY-SA 4.0 (May be cropped or resized)
Cuculus poliocephalus
Range
East Asia and the Himalayas; winters in East Africa and Sri Lanka
The lesser cuckoo is a cuckoo native to East Asia and the Himalayas, which winters in East Africa and Sri Lanka (Wikipedia, general species account).
That one-line account is the only source read for the Bhutan guide. No description, size, call, habitat or breeding information was found, so none is stated, and the entry is kept as short as the evidence allows.