Numenius borealis 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Scolopacidae

Scientific Name: Numenius borealis
Species Authority: (Forster, 1772)
Common Name(s):
English Eskimo Curlew
Spanish Zarapito Boreal, Chorlo Polar, Chorlito Esquimal, Zarapito Esquimal, Zarapito Polar
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.
Identification information: 29-34 cm. Small cinnamon-coloured curlew. Similar spp. Little Curlew N. minutus is similar, but N. borealis is larger, longer winged (extending beyond tip of tail), shorter legged, cinnamon not buffish below with heavily barred breast and "Y" shaped marks on flanks. Small size (25% smaller than Whimbrel N. phaeopus) eliminates all other species. Voice Flight call reportedly a rippling tr-tr-tr and a soft whistle bee bee.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered (Possibly Extinct) D ver 3.1
Year Published: 2015
Date Assessed: 2015-10-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A.
Contributor(s): Clay, R., Crockford, N., Gill, R.E., Gratto-Trevor, C., Hoffman, R., Parr, M. & Reed, E.
Facilitator/Compiler(s): Benstead, P., Bird, J., Butchart, S., Clay, R., Isherwood, I., Pilgrim, J., Sharpe, C J, Symes, A., Wege, D. & Ashpole, J
This species has not been recorded with certainty since 1963 (and none have been confirmed on the wintering grounds since 1939). It was formerly abundant, but declined rapidly over a century ago as a result of hunting and habitat loss. However, it cannot yet be presumed to be Extinct until all potential breeding areas have been surveyed, and the series of occasional unconfirmed reports ceases. Any remaining population is likely to be tiny, and for these reasons it is treated as Critically Endangered (Possibly Extinct).

Date last seen: 1963
Previously published Red List assessments:
2013 Critically Endangered (CR)
2012 Critically Endangered (CR)
2009 Critically Endangered (CR)
2008 Critically Endangered (CR)
2004 Critically Endangered (CR)
2000 Critically Endangered (CR)
1996 Critically Endangered (CR)
1994 Critically Endangered (CR)
1988 Threatened (T)

Geographic Range [top]

Range Description: Numenius borealis bred at (and presumably between) the Bathurst peninsula and Point Lake in Northwest Territories, Canada (Gill et al. 1998), and perhaps also Alaska, USA. Birds migrated across Hudson Bay to Labrador (and New England, USA), and through the Caribbean to Argentina (especially the Pampas), and possibly Uruguay, Paraguay (R. Clay in litt. 2003), southernmost Brazil and Chile south to Patagonia (Gill et al. 1998). The return migration was probably along the Pacific coast, through Central America, across the Gulf of Mexico to the Texas coast and northwards through the prairies. It probably numbered hundreds of thousands, but declined rapidly in the 1870s-1890s to become very rare in the 20th century (Gill et al. 1998, Graves 2010). The last irrefutable record was of a specimen collected in Barbados in 1963 (Roberts et al. 2010). Since then there have been no confirmed records (none from the wintering grounds in South America since 1939), only several unconfirmed reports during 1981-2006 (Gill et al. 1998, M. Parr in litt. 2003, C. L. Gratto-Trevor in litt. 2004, R. Hoffman in litt. 2006, N. Crockford in litt. 2008), with the latest unconfirmed sighting from Barbados in September 2012 (E. Reed in litt. 2012). The population (if one persists) must be tiny (Gill et al. 1998).

Countries occurrence:
Possibly extinct:
Argentina; Brazil; Canada; Chile; Paraguay; United States
Regionally extinct:
Barbados; Mexico; Uruguay
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 1
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (metres): 350
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Any remaining population is assumed to be tiny (numbering fewer than 50 individuals and mature individuals), as there have been no confirmed sightings since the early 1960s.
Current Population Trend: Unknown
Additional data:
Number of mature individuals: 1-49 Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Habitat and Ecology: It bred (May-August) in treeless arctic tundra at 180-335 m, comprising grassy meadows with birch (Betula) and sedge (Carex) (Gill et al. 1998). On autumn migration (July-October), it favoured ericaceous heath, crowberries Empetrum nigrum, pastures and intertidal flats (Gill et al. 1998). Winter habitat was possibly wet pampas grasslands, intertidal and semi-desert areas (Gill et al. 1998). On return migration (March-May), it favoured burnt areas in tall grass and mixed-grass prairies, and Rocky Mountain Grasshopper Melanoplus spretus was a key food source (Gill et al. 1998). It was gregarious, with traditional autumn migration sites (Gill et al. 1998).

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 10.1
Movement patterns: Full Migrant
Congregatory: Congregatory (and dispersive)

Threats [top]

Major Threat(s): Large-scale spring hunting in North America partially explains the species's near-extinction, but there was no recovery after hunting was outlawed and abandoned in c. 1916 (Gill et al. 1998). The main cause is almost certainly the near total loss of prairies to agriculture, compounded by the suppression of prairie wildfires and the extinction of M. spretus (Gill et al. 1998). The widespread conversion of the pampas began after the main decline, but has hindered any possible recovery (Gill et al. 1998).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CITES Appendix I. CMS Appendix I and II. It is protected in the USA, Canada, Argentina and Mexico. Its status has been fully documented, and identification details publicised (Gill et al. 1998). Breeding and wintering areas have been surveyed, and reported breeding sites investigated (Blanco et al. 1993, Gill et al. 1998, C. L. Gratto-Trevor in litt. 1999). An Environment Canada species recovery plan recommends that no recovery action be undertaken other than continued monitoring of reported sightings (Environment Canada 2007).

Conservation Actions Proposed
Continue cooperative international assessments of historical sites (Blanco et al. 1993, C. L. Gratto-Trevor in litt. 1999). Survey heath tundra along the Labrador coast during August-September and historic breeding grounds prior to the initiation of development projects (C. L. Gratto-Trevor in litt. 1999). Investigate any credible sightings (C. L. Gratto-Trevor in litt. 1999). Expand prairie habitat, and employ prescribed burnings (C. L. Gratto-Trevor in litt. 1999).

Citation: BirdLife International. 2015. Numenius borealis. The IUCN Red List of Threatened Species 2015: e.T22693170A79178546. . Downloaded on 31 May 2016.
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