• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic note
Tringa semipalmata (del Hoyo and Collar 2014) was previously placed in the genus Catoptrophorus as C. semipalmatus.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: http://www.aerc.eu/DOCS/Bird_taxa_of_the_WP15.xls.
Cramp, S. and Simmons, K.E.L. (eds). 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
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. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2024	Least Concern
2016	Least Concern
2012	Least Concern
2009	Least Concern
2008	Least Concern
2004	Least Concern
2000	Lower Risk/Least Concern
1994	Lower Risk/Least Concern
1988	Lower Risk/Least Concern

Migratory status	full migrant	Forest dependency	does not normally occur in forest
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	16,300,000 km2	medium
Extent of Occurrence (non-breeding)	37,900,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	250000 mature individuals	good	estimated	2023
Population trend	decreasing	-	estimated	2010-2028
Rate of change over the past 10 years/3 generations (longer of the two periods)	6-15%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	6-15%	-	-	-
Generation length	5.9 years	-	-	-
Number of subpopulations	2	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: It has a large estimated population size of 250,000 mature individuals (Partners in Flight 2023).

Trend justification: Considering its population trend over three generations (c. 18 years), the data presented in Smith et al. (2023) indicate a slow decline of c. 10%, albeit with large confidence intervals. This is broadly consistent with evidence of similar rates of decline from the Breeding Bird Survey (c. 7%; Ziolkowski Jr et al. 2022), eBird (c. 6%; Fink et al. 2023) and Partners in Flight (2023; c. 15%). In recent years, a steeper decline has been recorded on the Pacific coast by the Migratory Shorebird Project (unpublished data), although this covers a relatively small proportion of the population. Conversely, data from the Christmas Bird Count (Meehan et al. 2022) indicate a stable population. Overall the global population is estimated to have declined by 6-15% over the past three generations.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Anguilla (to UK)	extant	native
Antigua and Barbuda	extant	native
Argentina	extant	native
Aruba (to Netherlands)	extant	native
Bahamas	extant	native
Barbados	extant	native
Belize	extant	native
Bermuda (to UK)	extant	native
Bonaire, Sint Eustatius and Saba (to Netherlands)	extant	native			yes
Brazil	extant	native
Canada	extant	native		yes		yes
Cayman Islands (to UK)	extant	native
Chile	extant	native
Colombia	extant	native
Costa Rica	extant	native			yes
Cuba	extant	native
Curaçao (to Netherlands)	extant	native			yes
Dominica	extant	native
Dominican Republic	extant	native
Ecuador	extant	native			yes
El Salvador	extant	native
Finland	extant	vagrant
France	extant	vagrant
French Guiana	extant	native
Grenada	extant	native
Guadeloupe (to France)	extant	native			yes
Guatemala	extant	native
Guyana	extant	native
Haiti	extant	native
Honduras	extant	native
Jamaica	extant	native			yes
Martinique (to France)	extant	native
Mexico	extant	native
Montserrat (to UK)	extant	native
Nicaragua	extant	native
Norway	extant	vagrant
Panama	extant	native
Peru	extant	native
Portugal	extant	vagrant
Puerto Rico (to USA)	extant	native
Sint Maarten (to Netherlands)	extant	native			yes
St Barthelemy (to France)	extant	native
St Kitts and Nevis	extant	native
St Lucia	extant	native
St Martin (to France)	extant	native			yes
St Pierre and Miquelon (to France)	extant	native				yes
St Vincent and the Grenadines	extant	native
Suriname	extant	native
Trinidad and Tobago	extant	native				yes
Turks and Caicos Islands (to UK)	extant	native
United States Minor Outlying Islands (to USA)	extant	vagrant
Uruguay	extant	vagrant			yes
USA	extant	native		yes
Venezuela	extant	native
Virgin Islands (to UK)	extant	native	yes
Virgin Islands (to USA)	extant	native	yes

Country/Territory	IBA Name
Costa Rica	Nicoya Gulf mangroves and coastal areas
French Guiana	Ile de Cayenne
French Guiana	Littoral
French Guiana	Littoral Kourou
French Guiana	Littoral Macouria
French Guiana	Littoral Sinnamary
French Guiana	Plaine Kaw et Pointe Béhague
Mexico	Área de San Quintín
Mexico	Bahía Magdalena-Almejas
Mexico	Bahía Santa María
Mexico	Complejo Lagunar Ojo de Liebre
Mexico	Complejo Lagunar San Ignacio
Mexico	Delta del Río Colorado
Mexico	Ensenada de Pabellones
Mexico	Istmo de Tehuantepec - Mar Muerto
Panama	Upper Bay of Panamá
USA	Cape Hatteras National Seashore

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Marine Intertidal	Mud Flats and Salt Flats	suitable	non-breeding
Marine Intertidal	Rocky Shoreline	suitable	non-breeding
Marine Intertidal	Salt Marshes (Emergent Grasses)	major	non-breeding
Marine Intertidal	Salt Marshes (Emergent Grasses)	major	breeding
Marine Intertidal	Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc	suitable	non-breeding
Marine Intertidal	Shingle and/or Pebble Shoreline and/or Beaches	suitable	non-breeding
Marine Intertidal	Tidepools	suitable	non-breeding
Wetlands (inland)	Bogs, Marshes, Swamps, Fens, Peatlands	major	breeding
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation
Agriculture & aquaculture	Livestock farming & ranching - Small-holder grazing, ranching or farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation
Agriculture & aquaculture	Marine & freshwater aquaculture - Industrial aquaculture	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Unknown		Unknown
		Stresses Species mortality
Residential & commercial development	Commercial & industrial areas	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Residential & commercial development	Tourism & recreation areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Species disturbance

Purpose	Scale
Food - human	subsistence, national

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Recommended citation
BirdLife International (2024) Species factsheet: Willet Tringa semipalmata. Downloaded from https://datazone.birdlife.org/species/factsheet/willet-tringa-semipalmata on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/12/2024.