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White-rumped Swiftlet - BirdForum Opus

Subspecies A. s. assimilis
Photo © by Matalevu
Pacific Harbour, Fiji, 16 July 2006.

Alternate name: Pacific White-rumped Swiftlet

Aerodramus spodiopygius


Subspecies A. s. assimilis
Photo © by Mat & Cathy
Nadi, Fiji, September 2008.

10–11½ cm(4-4¼ in) A small, polytypic Swiftlet of several islands in the South Pacific. Very similar to Australian Swiftlet, but no range overlap.

  • Tail deeply forked
  • Clear white or pale gray rump, varying geographically in paleness
  • Most subspecies much paler below than Uniform Swiftlet
  • Pale grey lower breast and belly usually merge into darker throat and contrast with darker cap, but sometimes throat is paler.
  • Sooty-brown upperparts

Juvenile has pale fringes on wings.

Similar Species

Plumage, size, wing shape and flight actions are intermediate between Satin Swiftlet and Uniform Swiftlet. Differs from Glossy Swiftlet by pale rump-band, hardly any gloss on upperparts, ill-defined paler lower breast and belly, no white on underwing, no white tail-spots, and shape and flight action. Also differs from Satin Swiftlet on Admiralties by broader white rump, and on Vanuatu and New Caledonia by narrower white rump. From Uniform Swiftlet by broad white rump, blacker upperparts, paler lower breast and belly, and shape and flight action. From Whitehead's Swiftlet by flight action, smaller size, clearer whiter rump-band, often paler lower breast and belly, and deeper-forked tail.


Islands in the South Pacific, west of New Guinea: Bismarck Archipelago, New Ireland, New Britain, Solomon Islands, Vanuatu, New Caledonia, Fiji, Tonga and Samoa.
Common to abundant in most of its range. Vagrant to New Zealand.


Forms a superspecies with Philippine Swiftlet, Moluccan Swiftlet, Mountain Swiftlet and Australian Swiftlet. The last three have been considered to be conspecific with this species. Atiu Swiftlet Aerodramus sawtelli may be another subspecies of this species. Also placed in composite species Aerodramus francicus (Grey-rumped Swiftlet, now only Mascarene Swiftlet). Like other Aerodramus Swiftles this species is often placed in Collocalia.


This is a polytypic species. Eleven subspecies are currently recognized[1].

  • A. s. delichon – Manus I. (Admiralty Islands)
  • A. s. eichhorni – Bismarck Archipelago (Mussau I. in St. Matthias group)
  • A. s. noonaedanae – Bismarck Archipelago (New Ireland and New Britain)
  • A. s. reichenowi – Southern and e Solomon Islands
  • A. s. desolatus – Solomon Islands (Duff, Swallow and Santa Cruz)
  • A. s. epiensis – Banks Islands and n Vanuatu to Epi Islands
  • A. s. ingens – S Vanuatu
  • A. s. leucopygius – Loyalty Is and New Caledonia.
  • A. s. assimilis – Fiji.
  • A. s. townsendi – Tonga.
  • A. s. spodiopygius – Samoa.


Found over a wide range of habitats, from lowlands up to highlands and montane forests.



Feeds insects, taken in flight. Often foraging in big groups, sometimes with other Swiftlets and Swifts.


Breeds in colonies in caves, overhanging rocks, under fallen trees or even in human settlements in cave-like circumstances. Capable of echolocation. Builds a bracket-shaped nest made of vegetable matters hold together with saliva and attached to cliff or wall. Lays one to two eggs.


Echolocates with clicks. Occasional rattling chatter or trill, usually 3–10 notes in a continuously repeated rhythmic phrase.


This species is resident, however a vagrant to New Zealand is recorded.


  1. Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2019. The eBird/Clements Checklist of Birds of the World: v2019. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
  2. Chantler, P. & Boesman, P. (2019). White-rumped Swiftlet (Aerodramus spodiopygius). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/55273 on 13 December 2019).
  3. Chantler, P. & Driessens, G. (1995). Swifts: A Guide to the Swifts and Treeswifts of the World. Pica Press, East Sussex.
  4. Dutson, G. (2011) Birds of Melanesia, Christopher Helm, London.

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