Case Summary for:

Submission No 235: House Swift Apus affinis, Crab Creek River Mouth, Roebuck Bay, WA. 8 February 1998. Submitted by: D. Rogers.

Verdict: Accepted

A record that concerns the sighting of two swifts for a period of several minutes at the Crab Creek river mouth close to the Broome bird observatory in Roebuck Bay, WA. Observations were made in good light conditions only moments after sightings of Fork-tailed Swift Apus pacificus. It was estimated that the birds were about 40m above at a distance ranging from 30 to 60m.

An excellent account of the circumstances behind the sighting has been provided to the committee along with field notes from both observers (D. Rogers & P. Battley). The sketches taken at the time of the sighting highlight the excellent views obtained and are particularly convincing. Key features that eliminate other swifts and swallows include:

  • Square, broad tail with no trace of a fork (and no sign of moult).
  • Extensive white throat, rather cleanly cut at lower boundary.
  • Clean white rump-band.
  • More thickset build than Fork-tailed Swift (including shorter / blunter wings).
  • Lack of buff scaling to underparts.

The only Australian specimen of A. affinis is referable to the subspecies subfurcatus, which falls within the A. nipalensis group of Sibley & Munroe (1990). It would therefore seem likely that other Australian records such as this one would also fall into this group. Present Australian taxonomy treats the matter as unresolved and follows A. affinis (Christidis & Boles 1994). The committee has no hesitation in unanimously accepting this record as A affinis. which represents only the 3rd record of this species to be accepted by the committee.

References and Bibliography

  • Christidis, L & Boles, W.E. 1994. The Taxonomy and Species of Birds of Australia and its Territories. R.A.O.U. Monograph 2. RAOU, Hawthorn East.
  • Robertson, D.G. 1980. First record of the House Swift Apus affinis in Australia. Australian Birdwatcher 8, 239 - 242.
  • Sibley, C.G. & Munroe, B.L., Jr. 1990. Distribution and Taxonomy of Birds of the World. Yale University Press, New Haven.

Tony Palliser
Chairman Birds Australia Rarities Committee (BARC)