Himalayan swiftlet
| Himalayan swiftlet | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Apodiformes |
| Family: | Apodidae |
| Genus: | Aerodramus |
| Species: | A. brevirostris |
| Binomial name | |
|
Aerodramus brevirostris (Horsfield, 1840) |
|
| Synonyms | |
|
Collocalia brevirostris Deignan, 1955 |
|
Collocalia brevirostris Deignan, 1955
The Himalayan swiftlet (Aerodramus brevirostris) is a small swift. It is a common colonial breeder in the Himalayas and Southeast Asia. Some populations are migratory.
This swiftlet was formerly placed in the genus Collocalia. Two of its five subspecies are frequently given full species status, A. b. rogersi as the Indochinese swiftlet, Aerodramus rogersi, and the isolated Javan form A. b. vulcanorum as the volcano swiftlet, Aerodramus vulcanorum.
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.
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.
The Himalayan swiftlet has a twittering chit-chit roosting call, and also has a piercing teeree-teeree-teeree call.
What distinguishes many, but not all, swiftlet species from other swifts and indeed almost all other birds( the Oilbird being an exception) is their ability to use a simple but effective form of echolocation to navigate in through the darkness of the caves where they roost at night and breed. With the present species, at least vulcanorum is known to echolocate.
Unlike bats, the swiftlets make clicking noises for echolocation that are well within the human range of hearing. Two broadband pulses are separated by a slight pause. The length of the pause shortens as light becomes poorer. The clicks are followed by the twittering call when the bird is approaching its nest.
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Wikipedia