Polynesian sandpiper

Taxobox
name = Polynesian sandpipers
regnum = Animalia
phylum = Chordata
classis = Aves
ordo = Charadriiformes
familia = Scolopacidae
genus = "Prosobonia"
genus_authority = Bonaparte, 1850
subdivision_ranks = Species
subdivision = See text.
synonyms ="Aechmorhynchus" Coues, 1874

The two to four species of Polynesian sandpipers, the only members of the genus "Prosobonia", are small wading birds confined to remote Pacific islands of French Polynesia. Only one species now exist, and it is rare and little known. This bird is sometimes separated in the genus "Aechmorhynchus", restricting the genus to the extinct southern forms.

The Tuamotu Sandpiper, "P. cancellata", is a unique short-billed all-brown wader previously found over a large area of the Pacific, but now confined to a few islands in the Tuamotu archipelago and still declining. Its decline appears to be due to human habitation encroachment and introduced mammals. It feeds on insects, but takes some vegetable material from its coastal haunts. It nests on the ground, and has a soft piping call.

The extinct Tahitian Sandpiper, "P. leucoptera" of Tahiti was similar in size and shape to "P. cancellata". It had brown upperparts, reddish underparts, a white wingbar, and some white on the face and throat. It became extinct in the 19th century, and little is known of it.

There was a similar bird on Moorea which differed in some minor details from "P. leucoptera", notably the larger extent of white in the wing, and has been described as White-winged Sandpiper ("P. ellisi"). However, although two species are generally listed, the question whether they actually did constitute separate species is probably unresolvable as only a single specimen of exists today, apart from some contemporary paintings.

From Mangaia in the Cook Islands, Ua Huka in the Marquesas, and the remote South Pacific Henderson Island (Wragg 1995), subfossil remains of "Prosobonia" have been recovered but not yet named. The first of these was almost certainly more closely related to the Tahiti and Moorea populations than to the Tuamotu Sandpiper, but the exact nature of their relationship is unlikely to be resolved anytime soon. It disappeared in the early-mid 1st millennium AD, probably not long after 300 AD.

The Ua Huka and Henderson forms can be assumed to have been closer to the living species. The latter, a distinct species with long legs and short wings (Wragg & Weisler 1994), became extinct only about 1000 years after the Mangaia form, some time after 1200.

References

* Bonaparte, Charles Lucien Jules Laurent (1850): Note sur plusieurs familles naturelles d'Oiseaux, et descriptions d'espèces nouvelles. "Comptes Rendus Hebdomadaire des Seances de l'Academie des Sciences, Paris" 31: 561-564. [Article in French] [http://gallica.bnf.fr/ark:/12148/bpt6k29887 Fulltext at Gallica]

* Wragg, Graham M. (1995): The fossil birds of Henderson Island, Pitcairn Group: natural turnover and human impact, a synopsis. "Biol. J. Linn. Soc." 56(1-2): 405–414. [http://www.ingentaconnect.com/content/ap/bj/1995/00000056/00000001/art00076 HTML abstract]

* Wragg, Graham M. & Weisler, Graham M. (1994): Extinctions and new records of birds from Henderson Island, Pitcairn group, south Pacific Ocean. "Notornis" 41(1): 60-70. [http://www.notornis.org.nz/free_issues/Notornis_41-1994/Notornis_41_1_61.pdf PDF fulltext]