Memorandum to:                     The Director of Birds Australia

 

 

From:                                       Birds Australia Rarities Committee (BARC)

 

 

Date:                                        25th January 2007

 

 

Voting Members:                     Tony Palliser                 Glenn Holmes

Rohan Clarke                 Danny Rogers

                                                John Hatch                    Andrew Silcocks

                                                Jamie Matthew              Mike Carter

 

cc:                                            Keith Brandwood

 

 

 

Submission No 481: American Golden Plover Pluvialis dominica, Shoalhaven, NSW, 1st April 2006.

 

 

Verdict:  Not Accepted

 

 

This case concerns the observation of a plover considered by the observer to be a possible American Golden Plover Pluvialis dominica. The bird was seen at the Shoalhaven estuary, Comerong Island, NSW in association with Pacific Golden Plover P. fulva and was moulting into alternate (summer) plumage.

 

Comparing this individual directly with P. fulva the observer noted a bulkier appearance, with seemingly shorter legs and a stubbier, perhaps shorter bill. Additionally bulging white sides on the breast differed from the similar plumaged fulva present and these features alerted the observer to the possibility of dominica. The wings and upperparts had progressed extensively into alternate plumage, revealing a fresh golden appearance speckled with black and white.  The primary projection was observed to fall well beyond the tail tip and appeared longer than associated birds. The primary extension beyond the tertials was not determined exactly. The observer admitted that plumage variation and known overlap of features between the two species makes identification extremely difficult. However, the above features do deserve consideration and provide the groundwork for careful scrutiny of Golden Plover in Australia.

 

This submission is professionally researched and the submission promising in many respects. However following careful consideration members felt that the “rear-end” was not seen in sufficient detail to clench the primary projection, and without this character, there is nothing in the submission that could be classed as completely diagnostic. Although other features certainly suggest dominica.

 

Notes on particular aspects of the submission:

 

  • General appearance: Good for dominica, but rather subjective, especially in April when Pacific Golden Plovers are undertaking pre-migratory mass gain and can look plump and the rear end can look proportionately skinny because unlike the body, it is invariant in bulk (no subcutaneous fat under the feathers).

 

  • Bill length relative to head size– fits dominica better than fulva, but overlap has been thoroughly documented in the paper by Johnson & Johnson (2004).

 

 

  • White forehead and sides (and possibly undertail coverts) – None of these features are completely diagnostic in themselves, as there is plumage overlap. Nevertheless, the fact that all of these characters fitted dominica better than fulva is the most convincing aspect of the submission. But there is just too much overlap in these characters to be confident; HANZAB suggest as many as 10% of male fulva may have essentially black flanks and undertail coverts.

 

  • Upperparts – Again, looks better for dominica, but too much overlap in this character to be confident that fulva can be ruled out.

 

  • Wing length – From the photographs, the wings do not look remarkably long for fulva and the bird appears to lack the characteristic elegance to the rear end. Nevertheless, the observer paid a lot of attention to this character, and his assessment was that the tail fell well short of the primary tips. It’s hard to imagine that this assessment would have been influenced by moult, as in the austral autumn and late in pre-alternate moult, both primaries and tail should be fully grown.

 

  • The difference in projection of primaries beyond tail tip in dominica (12 – 22 mm) can be quite close to that in the longest-winged fulva (0-9 mm) and there isn’t sufficient detail to tell how extensive the projection was.

 

To date there remains only one confirmed record of this species for Australia, that being a worn and faded juvenile seen and photographed at Byron Bay, NSW on 8 November 1994 (BARC case no. 189). Detailed field notes and photographs were invaluable in confirming the identification of that individual.

 

References and Bibliography

  • Barter, M., (1988), ‘Biometrics and moult of Lesser Golden Plover Pluvialis dominica fulva in Victoria’, The Stilt 13: 15-19.
  • Chandler, R.J., (1989), The Macmillan Field Guide to North Atlantic Shorebirds, Macmillan, London.
  • Golley, M & Stoddart, A., (1991), ‘Identification of American and Pacific Golden Plovers’, Birding World: 4: 195-204

·         HANZAB; Marchant, S. & Higgins, P.J. (Eds.) (1993), Handbook of Australian, New Zealand & Antarctic Birds Vol. 2, Raptors to Lapwings, Oxford, Melbourne. (Note: the only currently available ID info written from an Australian/southern hemisphere perspective).

  • Hayman, P., Marchant, J. & Prater, T. (1986), Shorebirds; an Identification Guide to the Waders of the World, Croom Helm, Sydney.
  • Johnson, O.W. and Johnson, P.M., (2004), ‘Morphometric features of Pacific and American Golden-Plovers with comments on field identification’, Wader Study Group Bulletin 103: 42-49.
  • Lewington I, Alstrom P. & Colston P., (1991), A Field Guide to the Rare Birds of Britain and Europe, HarperCollinsPublishers, Great Britain.
  • Paulson, D. (2005), Shorebirds of North America, The Photographic Guide, Christopher Helm, London
  • Rosair D. & Cottridge D., (1995), Photographic Guide to Waders of the World. Hamlyn, Great Britain.
  • Stoddard, A., (1989), ‘Pacific Golden Plover in Norfolk’, Birding World 2: 244-247

 

 

Tony Palliser

Chairman, Birds Australia Rarities Committee