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Bristle-thighed Curlew Numenius tahitiensis

Justification
This species is listed as Vulnerable because its population is now small and believed to be declining, probably largely as a result of predation and hunting on its wintering grounds, when perhaps more than 50% of adults are flightless during autumn moult.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Identification
40-44 cm. Medium-sized curlew. Well-marked head pattern. Dark lateral crown and eye-stripes contrast with pale crown centre and supercilium. Upperparts spotted buff, underparts streaked buff. Dark cinnamon underwing, barred brown. Unmarked cinnamon rump and uppertail. Blue-grey legs. Flesh-coloured base to brown, longish and heavy bill. Juvenile virtually unstreaked underparts and large buff spots on wing-coverts and upperparts. Similar spp. Whimbrel N. phaeopus lacks cinnamon rump, has thinner and more pointed bill, less cinnamon underparts. Eskimo Curlew N. borealis is smaller. Long-billed Curlew N. americanus has different bill shape and head pattern. Voice Short chi-u-it, whistling whe-whe-whe-whe, ringing whee-wheeoo.

Distribution and population
Numenius tahitiensis breeds on the lower Yukon River and central Seward Peninsula in western Alaska, USA (Collar et al. 1992). Suggestions that it breeds in Russia are unsupported (R. E. Gill in litt. 1999, 2003). It winters on oceanic islands, including the Hawaiian Islands (USA), US Minor Outlying Islands, Northern Mariana Islands (to USA), Federated States of Micronesia, Marshall Islands, Nauru, Kiribati, Tuvalu, Tokelau (to New Zealand), Fiji, Tonga, Niue (to New Zealand), Samoa, American Samoa, Cook Islands, and French Polynesia, also reaching the Solomon Islands, Norfolk Island (to Australia), Kermadec Islands (New Zealand), Pitcairn Islands (to UK) (notably Oeno) and Easter Island (Chile) (Vilina et al. 1992, Brooke 1995b, Y. Vilina in litt. 1999). The breeding population numbers c.7,000 birds, but c.3,000 subadults over-summer on Pacific islands (P. Donaldson in litt. 1999, SPREP 1999).

Population justification
Morrison et al. (2001) estimated the population to number 7,000 breeding mature individuals and 3,000 immatures, giving a total of 10,000 individuals.

Trend justification
This species's population is suspected to be decreasing at a moderate rate, owing mainly to the expected impacts of predation and hunting on its wintering grounds.

Ecology
It breeds in dwarf-shrub tundra at 100-350 m during May-July. Birds congregate in the Yukon-Kuskokwin Delta in August, and migrate south, mostly bypassing the Northwestern Hawaiian Islands to make landfall after 6,000 km or more (Marks and Redmond 1994b, Gill 1999). It winters on coral reefs, sandy beaches, intertidal flats, rocky shores and in palm forests and dense vegetated understorey (Gill 1999, R. E. Gill in litt. 1999, 2003). It is long-lived (15-23 years), forms long-term monogamous pairs, and is highly faithful to breeding and wintering sites (Gill 1999).

Threats
Introduced predators, especially dogs, but also cats and possibly pigs are likely to predate flightless birds on wintering grounds. The species may suffer some loss and degradation of its habitats through clearance for coconut plantations and proliferation of coconut groves where not harvested (P. Raust in litt. 2012). Hunting for food is localised, particularly previously in the Tuamotus, and recent reports suggest it may also be a threat in the Marshall Islands, Carolines, US Minor Outlying Islands and Hawaiian offshore islands (G. Allport in litt. 2006). Breeding birds are predated by several species of raptor, Parasitic Jaegers Stercorarius parasiticus, Common Ravens Corvus corax and foxes. Gold mining is a potential future threat in Alaska (R. E. Gill in litt. 1999, 2003). Ingestion of lead paint on Midway Island needs to be investigated (it was recently identified as a problem in seabirds) (R. E. Gill in litt. 1999, 2003). The species is also potentially threatened by the impacts of projected climate change through changes and geographical shifts in habitat and rising sea levels.


Conservation Actions Underway
CMS Appendix II. Most breeding and staging grounds are well-protected (Gill 1999). The Hawaiian Islands National Wildlife Refuge protects several wintering and stop-over sites. Protection and management of habitat at Kahuku on O'ahu has facilitated an increase in the local wintering population (P. Donaldson in litt. 1999). Conservation Actions Proposed
Survey key historical sites (Marks and Redmond 1994a, SPREP 1999), and identify migratory stop-over sites and sites with high concentrations of wintering birds (Marks and Redmond 1994a, SPREP 1999). Monitor population trends on its breeding grounds (Marks and Redmond 1994a, P. Donaldson in litt. 1999). Assess the harvesting rate (SPREP 1999). Protect and manage key islands, atolls and other wintering sites (Marks and Redmond 1994a, P. Donaldson in litt. 1999). Initiate a coordinated conservation programme involving stakeholders in the U.S. and Pacific nations (P. Raust in litt. 2012).


References
Brooke, M. De L. 1995. The modern avifauna of the Pitcairn Islands. Biological Journal of the Linnean Society 56: 199-212.

Collar, N. J.; Gonzaga, L. P.; Krabbe, N.; Madroño Nieto, A.; Naranjo, L. G.; Parker, T. A.; Wege, D. C. 1992. Threatened birds of the Americas: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, Cambridge, U.K.

Dutson, G. Zosterops albogularis = PE?

Gill, R. 1998. Trouble in paradise: the Bristle-thighed Curlew. WWF Arctic Bulletin: 12-13.

Marks, J. S. 1993. Molt of Bristle-thighed Curlews in the Northwestern Hawaiin Islands. The Auk 110: 573-587.

Marks, J. S.; Redmond, R. L. 1994. Conservation problems and research needs for Bristle-thighed Curlews Numenius tahitiensis on their wintering grounds. Bird Conservation International 4: 329-341.

Marks, J. S.; Redmond, R. L. 1994. Migration of Bristle-thighed Curlews on Laysan Island: timing, behavior and estimated flight range. Condor 96: 316-330.

Morrison, R. I. G.; Gill, R. E.; Harrington, B. A.; Skagen, S.; Page, G. W.; Gratto-Trevor, C. L.; Haig, S. M. 2001. Estimates of shorebird populations in North America. Canadian Wildlife Service, Ottawa, Canada.

SPREP. 1999. Proceedings of the Polynesian Avifauna Conservation Workshop held in Rarotonga, 26-30 April 1999.

Vilina, Y. A.; Larrea, A.; Gibbons, J. E. 1992. First record of Bristle-thighed Curlew Numenius tahitiensis in Easter Island, Chile. Wader Study Group Bulletin 66: 43-44.

Further web sources of information
Audubon WatchList

Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Harding, M., Pilgrim, J., Symes, A., Taylor, J.

Contributors
Bird, J., Donaldson, P., Gill, R., Raust, P., Vilina, Y.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Numenius tahitiensis. Downloaded from http://www.birdlife.org on 27/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/12/2014.

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Bristle-thighed curlew (Numenius tahitiensis) 0

Key facts
Current IUCN Red List category Vulnerable
Family Scolopacidae (Sandpipers, Snipes, Phalaropes)
Species name author (Gmelin, 1789)
Population size 7000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 45,300 km2
Country endemic? Yes
Links to further information
- Additional Information on this species