Justification This species was formerly widespread, but is now restricted to predator-free, usually uninhabited islands. It is listed as Endangered because it has a very small range overall, is currently known only from a few locations, and is likely to be undergoing a continuing decline owing to the effects of introduced species, and to a lesser extent, habitat degredation. If predators were to become established on Tenararo and Morane (which hold 80% of the population) the species would warrant uplisting to Critically Endangered.

Family/Sub-family Scolopacidae

Species name author (Gmelin, 1789)

Taxonomic source(s) Sibley and Monroe (1990, 1993)

Synonyms Prosobonia cancellatus Collar and Andrew (1988)

Identification 17 cm. Small sandpiper with very short, sharp bill. Variably mottled and streaked with dull brown, with bold white superciliary stripe. Black bill. Similar spp. Sanderling Calidris alba larger and much paler. Voice High squeaking note.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

1,300

decreasing

110 km²

Yes

Range & population Prosobonia cancellata is endemic to the Tuamotu Archipelago, French Polynesia, where it has declined throughout the last century. It formerly occurred on Kiritimati (= Christmas Island), Kiribati, where the type specimen was collected, though this record may constitute a distinct species¹². Only four islands are now thought to support populations: Tenararo (a minimum of 500 in 2001), Morane (a minimum of 530 in 2003), Reitoru (57 in 2003) and Tahanea (185 in 2003 and 59 in 2007). Elsewhere in the Tuamotu Archipelago one bird was seen on Aratika in 2007¹³, and otherwise small numbers of birds were reported in the 1980s and 1990s, most notably from Fakarava (reports from fishermen in the 1980s) and Anuanuraro (30-40 in 1990) ^{1,2,3,4,5,7,8,10,12}. There have been an increasing number of nil returns when islands where small numbers had been reported are re-surveyed, implying a continued decline correlated with the spread of rats Rattus spp and cats ¹². Consequently, populations on the latter three islands may already be extinct and records of small numbers of individuals elsewhere may refer to visiting (rather than established) birds². It is unlikely that many more populations will be discovered, the population is estimated to be 1300 individuals.

Ecology: It is found on upper beaches of coral rubble and sand amongst dwarf srubs (especially Scaevola, Messerschmidti and Guettarda) and scattered tall shrubs, as well as in adjacent areas of shrubland and interior of forest, especially open forest ^6,12. Dense stands of Pandanus are avoided ¹². The species is regularly reported along atoll shorelines and lagoon edges⁶, but it is thought they only frequent these habitats when attracted out of curiosity to the observers ¹². It is non-migratory but may visit islands where it does not nest⁶. Food, which comprises mainly invertebrates and some plant material, is gleaned from the vegetation of scrubs and trees and also from the surface of the ground ¹².

Threats The introduction of rats, particularly black rat Rattus rattus, and also cats, has probably eliminated the species from all but the most infrequently visited islands in the archipelago ^6,12. The establishment of coconut plantations is thought not to be a threat unless native undergrowth is also cleared ¹². However, the establishment of coconut plantations, and especially coprah plantations, increases the frequency of human visits to islands and consequently the likelihood of predator introduction ¹². Of particular concern is that the two neighbouring islands to Tenararo, where there is coprah, support rats Rattus spp. ¹². An additional concern is that visiting birdwatchers may accidentally introduce rats to Tenararo¹³.

Conservation measures underway Information on this species has been collected as a result of expeditions in 1999 and follow-up work in 2001 and 2003. Te Manu has developed an action plan to eradicate rats on Vahanga (adjacent to Tenararo) with technical support from the New Zealand Department of Conservation, however they are still seeking funding¹³.

Conservation measures proposed Maintain the predator-free status of Morane and Tenararo by restricting access. Eradicate predators from motus (islets) where the species is no longer present on the atolls Tahanea and Reitoru to allow it to re-colonise these naturally. Survey islands where historical records indicate that the species may still persist, particularly Maruta Sud and islands in the Duke of Gloucester Group⁹. Identify suitable islands for translocation, either rat- and cat-free or where eradication is possible⁹. Consider translocating birds to islands on which predators have been eradicated where the species never occurred but which supported now extinct species of Prosobonia. Develop a recovery plan⁹. Involve local people in the implementation of the recovery plan, with the species as its emblem, so that they associate it with increased coprah yields which will result from rat eradication.

References 1. C. Blanvillain in litt. (1999). 2. Blanvillain et al. (2002). 3. Holyoak and Thibault (1984). 4. Lacan and Mougin (1974). 5. Lovegrove et al. (1989). 6. Pratt et al. (1987). 7. P. Raust in litt. (1999). 8. Seitre and Seitre (1991). 9. SPREP (1999). 10. Thibault (1988). 11. P. Raust in litt. (2003). 12. R.J. Pierce and C. Blanvillain (2006). 13. P. Raust in litt. (2007).

Text account compilers Phil Benstead (BirdLife International), C. Blanvillain, Matt Harding (BirdLife International), Simon Mahood (BirdLife International), Andrew O'Brien (BirdLife International), John Pilgrim (BirdLife International), Alison Stattersfield (BirdLife International)

Contributors C. Blanvillain, Philippe Raust (Société d'Ornithologie de Polynésie "Manu")

IUCN Red List evaluators Stuart Butchart (BirdLife International), Simon Mahood (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Prosobonia cancellata. Downloaded from http://www.birdlife.org on 10/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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