LC
Willet Tringa semipalmata



Taxonomy

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.

IUCN Red List criteria met and history
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
Species attributes

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

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 -
Population
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 distribution
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

Important Bird and Biodiversity Areas (IBA)
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

Habitats & altitude
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  

Threats & impact
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

Utilisation
Purpose Scale
Food - human subsistence, national

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.