Himalayan Swiftlet

This 13–14 cm long swiftlet has swept-back wings that resemble a crescent or a boomerang. The body is slender, and the tail is forked. It is, in many respects, a typical swift, having narrow wings for fast flight, and a wide gape and small beak surrounded by bristles for catching insects in flight. Its legs are very short, preventing the bird from perching, but allowing it to cling to vertical surfaces. It is mainly grey-brown above and paler brown below. It has a pale grey rump and a pale patch above and behind the bill. The sexes are similar, but the juvenile has a less distinct rump. There are five subspecies, differing mainly in the rump tone. A. b. brevirostris breeds in the Himalayas east to Bangladesh, Myanmar and Thailand. This, the nominate race, is an altitudinal migrant, breeding up to above 4,500 m, but wintering between 900 and 2750 m altitude. A. b. innominata breeds in central China, and winters in southwestern Thailand and the Malay Peninsula. The rump is slightly darker grey than nominate brevirostris A. b. inopina breeds in southwestern China. This is the darkest-rumped race. A. b. rogersi the Indochinese swiftlet, breeds in eastern Myanmar, western Thailand and Laos. This is a small, pale-rumped race. A. b. vulcanorum the volcano swiftlet, breeds in Java, Indonesia on volcanic peaks. It has dark underparts and an indistinct pale grey rump. Over much of its range, this is the only swift, but in the south of its breeding area and much of its wintering range it can be very difficult to distinguish this species from other Collocalia swiftlets.