Asian House Martin

The Asian house martin is a migratory swallow of mainly blue-black upperparts and a white rump, with pale grey underparts. The nominate race is 12 cm long, dark steel blue above with a contrasting white rump, grey-washed white underparts and a slightly forked tail; the tail and upperwings are brownish-black and the underwings grey-brown. The legs and feet are brownish-pink and covered with white feathers, and the male is somewhat whiter below than the female, especially in fresh plumage. Its three subspecies breed in the Himalaya and in central and eastern Asia (Wikipedia, general species account).

It breeds in colonies, building mud nests under an overhang on a vertical cliff or a building wall. Both sexes build the nest, incubate the three or four white eggs and feed the chicks. It feeds on small insects taken in flight, usually high in the air, and the presence of terrestrial springtails and Lepidoptera larvae in the diet suggests food is sometimes picked from the ground (Wikipedia, general species account).