Crested Treeswift

The crested treeswift is a large, slender swift about 23cm long, a common resident breeder in the Indian subcontinent and mainland South-east Asia, including China. It was for some time considered the same species as the grey-rumped treeswift, but the two do not interbreed where their ranges overlap. In flight it has long, bowed wings and a deeply forked tail that usually looks narrow and pointed (Wikipedia, general species account).

Most birds live in the lowlands below 1,000m, in small groups flying in wide circles over open forest and occasionally perching on a tall, leafless tree. It lays one blue-grey egg, incubated by both sexes, in a nest so small that the incubating bird may look like a bump on a branch. Young birds have a dark grey head and wings with white-edged feathers and streakier plumage than adults. Roosting can be communal (Wikipedia, general species account).