Current Status of the Endangered Tuamotu Sandpiper Or Titi Prosobonia Cancellata and Recommended Actions for Its Recovery
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Current status of the endangered Tuamotu Sandpiper or Titi Prosobonia cancellata and recommended actions for its recovery R.J. PIERCE • & C. BLANVILLAIN 2 WildlandConsultants, PO Box 1305, Whangarei,New Zealand. raypierce@xtra. co. nz 2Soci•t• d'Omithologiede Polyn•sieFrancaise, BP 21098, Papeete,Tahiti Pierce,R.J. & Blanvillain, C. 2004. Current statusof the endangeredTuamotu Sandpiper or Titi Prosobonia cancellataand recommendedactions for its recovery.Wader StudyGroup Bull. 105: 93-100. The TuamotuSandpiper or Titi is the only survivingmember of the Tribe Prosoboniiniand is confinedto easternPolynesia. Formerly distributedthroughout the Tuamotu Archipelago,it has been decimatedby mammalianpredators which now occuron nearlyall atollsof the archipelago.Isolated sandpiper populations are currentlyknown from only four uninhabitedatolls in the Tuamotu.Only two of theseare currentlyfree of mammalianpredators, such as cats and rats, and the risks of rat invasionon themare high. This paper outlines tasksnecessary in the shortterm (within five years)to securethe species,together with longerterm actions neededfor its recovery.Short-term actions include increasing the securityof existingpopulations, surveying for otherpotential populations, eradicating mammalian predators on key atolls,monitoring key populations, and preparing a recovery plan for the species. Longer term actions necessaryfor recovery include reintroductions,advocacy and research programmes. INTRODUCTION ecologyof the TuamotuSandpiper as completelyas is cur- rently known, assessesthe threatsto its continuedsurvival, The TuamotuSandpiper or Titi Prosoboniacancellata is a and outlinesactions needed for its recovery. little-knownshorebird endemic to theTuamotu Archipelago. It is uniqueamongst sandpipers in that it is largely a seden- FORMER DISTRIBUTION OF PROSOBONIIDS tarybird of tropicalcoral atolls where it frequentsforest and shrublandhabitats. It hasno closeaffinities with otherliving The genusProsobonia contains one extantand many extinct speciesand is placedin its owntribe, the Prosoboniini, within taxa restrictedto easternPolynesia. The taxonomyof pro- the subfamily Tringinae or shanks (Zusi & Jehl 1970, soboniidsis not straightforwardand someworkers consider Piersma et al. 1996). All other speciesof prosoboniids, the Tuamotu SandpiperP. cancellata (parvirostris) to be includingflightless species, have become extinct during the distinct from the type specimenwhich is thought to have past 1,000 years(Wragg & Weisler 1994, Steadman1995, been collected at Kiritimati in the Line Islands in 1778 (see Steadman& Rollet 1996). Walters 1993 for discussion).Table 1 summarisesexisting Formerly widespreadthroughout the archipelago,the taxonomicinformation on the genusProsobonia. TuamotuSandpiper is now confinedto a small numberof The Kiritimati birds (Prosoboniacancellata, type local- islandsin theTuamotu, and is consideredan endangeredspe- ity), aswell asP. leucopteraof Tahiti andP. ellisi of Moorea cies (Birdlife International2000). Resultsof recentsurveys werelast seen alive in the 18thcentury and probably died out suggesta totalpopulation of little morethan 1,000 individu- then or soon after (Piersma et al. 1996). The Henderson als (Blanvillain et al. 2002, Pierce et al. 2003). There are no islandbirds died outbetween 1200 AD andthe 18thcentury recentdata on populationtrends. (Wragg & Weisler 1994). It is likely that the Marquesan This paper summarisesthe distribution,abundance and taxon alsodied out early in the settlementof thoseislands. Table 1. Extinct and living prosoboniidtaxa. Taxon Distribution Status Reference P. cancellata (type specimen) Consideredto have been collected Extinct c. 18th century Walters 1993 from Kiritimati (Line Islands) in 1778. P. cancellata (parvirostris) TuamotuArchipelago Confined to a small number of atolls Walters 1993, (Tuamotu Sandpiper) Piersma et al. 1996 P. leucoptera(Tahitian Sandpiper) Tahiti Extinct c. 18th century Piersma et al. 1996 P. ellisi (white-winged sandpiper) Moorea Extinct c. 18th century Walters 1991 P. new species HendersonIsland, Pitcairn Group Subfossil, extinct Wragg & Weisler 1994 P. new species MarquesasIslands Subfossil, extinct Steadman & Rollet 1996 P. new species Mangaia, Cook Islands Subfossil, extinct Steadman 1995 93 Bulletin 105 December 2004 94 Wader Study Group Bulletin TUAMOTU A RCHiPEL A GO * I•k• .Puk• :!5' 15' •N•$•ARO• • :•TENARUNC.• 20' Du• of gloo• GROUP• ß., ACTEON . N • • •ruteo '•*•9 t •M.n•r• Morane , CAPRICORN GAMBIER IS:LANDS 150' 145' Fig. 1. Map of the Tuamotu Archipelago(modified from Blanvillainet al. (2002)). FORMER DISTRIBUTION OF TUAMOTU SANDPIPER was seenduring a long stayon Tenarunga,two birdsduring a brief visit to Vahanga,none during a brief visit to Matu- Althoughall otherprosoboniids were extinctby the end of reivavao, but many hundredswere presenton Tenararao. the 19th century, the Tuamotu Sandpiperwas still wide- Maria was not visited during this trip, but local people spreadin the TuamotuArchipelago with recordsextending reportedseeing none in 1986 (Blainvillain et al. 2002). If the from Tepoto (north-westof Napuka) in the north (14øS) to Tuamotu Sandpiperhas disappeared from Matureivavao,it the Gambiersand Morane (about23øS) in the south(Fig. 1). hasdone so in recentyears only, as the specieswas consid- In the 1920s,Tuamotu Sandpipers were presentand breed- ered quite common in 1966 (Lacan & Mougin 1974) and ing in the Raevski Group (betweenTahanea and Hao) and they were also presentin 1970 and 1982 (Birdlife Interna- they were commonor abundanton four of the five atollsin tional 2000). Morane supported 150-200 birds in 1990 the Acteon Group centred on 21øS (Beck & Quayle in (Birdlife Intemational 2000). Holyoak & Thibault 1984). The Acteon Group atolls were Elsewherein the TuamotuArchipelago, only smallnum- Tenarunga(only onehalf of the islandfrequented), Tenararo, bers of birds were reportedin the 1980s and 1990s,mainly Matureivavao and Maria Islands in 1922, but on the fifth from islands in the central and northern Tuamotu. These islandin the group,Vahanga, they were rare with only four includedsingle birds on Rangiroaand neighbouringatolls, birdsbeing seen. Presumably they were alsocommon at this and small to moderate numbers on Tahanea, Fakarava, and time on Morane (where 150-200 birds were recorded in Anuanararo in the Duke of Gloucester Islands. There have 1990) and possiblyon someother southernTuamotu atolls, alsobeen an increasingnumbers of nil returns,such as from includingMarutea Sud where they were consideredmoder- the Raevski Group in 1999 where it was reported to be ately abundantin 1965 (Birdlife International2000), and on presentin the 1980s(Blanvillain et al. 2002). Details of all some central Tuamotu atolls, e.g. Tahanea,Fakarava and TuamotuSandpiper reports for 1900-2003 are setout in the Anuanararo where birds were reported in the 1980s and Appendix. 1990s. By the 1990s,Morane andTenararo were the only locali- CURRENT DISTRIBUTION OF THE TUAMOTU ties whereTuamotu Sandpipers were knownto be presentin SANDPIPER goodnumbers, and they had virtually disappearedfrom all of the Acteon Group where they had been commonin the A surveyof 10 atollsin the Tuamotuand AustralGroups in 1920s (Blanvillain et al. 2002). Thus, in 1999, only one bird 2003 foundthat Morane was a strongholdfor TuamotuSand- Bulletin 105 December 2004 Pierce & Blanvillain:Status of Tuamotu Sandpiper and recommended actions for its recovery 95 Fig. 2. Tuamotu Sandpiper on the shrub Messerschmidtia. pipersand smaller populations were also found on Reitoruand thesehabitats. Instead, it is more a bird of the upperbeaches Tahanea in the central and northern Tuamotu (Pierce et al. of coral rubble and sandamongst dwarf shrubsand scattered 2003). Thus in 2003 the following populationswere known: tall shrubs,as well as the adjacentareas of shrublandand interior of the forest (Figs 2 and 3). During surveys of ß Tenararo:500+ in November 2000 and July 2001 Tenararo in November 2000 and July 2001, the sandpipers (C. Blanvillain & R. Pierce pers. obs.) were distributed throughout the forest and especially the ß Morane: 530+ in March 2003 (Pierce et al. 2003) forest edges. On Morane, Reitoru and Tahanea in March ß Reitoru: 57 in March 2003 (Pierce et al. 2003) 2003, the preferredhabitat was openforest and particularly ß Tahanea: 185 in March 2003 (Pierce et al. 2003). shrubland dominated by Scaevola, Messerschmidtia and Guettarda. Dense stands of Pandanus were common on It is possiblethat small populationsof the Tuamotu Sand- Morane and thesewere largely avoided by Tuamotu Sand- piperscould persiston isolatedmotu (islets separatedfrom pipers. Elsewhere, observershave reported Tuamotu Sand- the main atoll) at Marurea Sud where they were considered pipersfrequenting atoll shorelinesand lagoonedges (Jutglar moderatelyabundant in 1965 (Birdlife International2000) 1996, Birdlife international 2000). During our surveys, and on other islands,e.g. in the Duke of GloucesterGroup shorelineswere rarely frequentedby the sandpipers,except and possiblyother atolls. when they were attractedout of curiosity to the observers (Pierce et al. 2003). ECOLOGY OF THE TUAMOTU SANDPIPER Food Habitat No detailed feeding studies have been carried out on the The atolls of the Tuamotu typically comprisean outer reef Tuamotu Sandpiperand most of the information presented behind which rock-poolsgive way to a beach of coral rub- below was obtainedduring population surveys by the authors. ble and sand,followed by a vegetatedzone extendingfor