View source for Willet

{{short description|Species of bird}}
{{other uses}}
{{Speciesbox
| image = Catoptrophorus semipalmatus edit.jpg
| image_caption =
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn">{{cite iucn |author=BirdLife International. |year=2024 |title=''Tringa semipalmata'' |volume=2024 |article-number=e.T22693319A263047127 |doi=10.2305/IUCN.UK.2024-2.RLTS.T22693319A263047127.en |access-date=2 August 2025}}</ref>
| taxon = Tringa semipalmata
| authority = ([[Johann Friedrich Gmelin|J. F. Gmelin]], 1789)
| subdivision_ranks = Subspecies
| subdivision =
* ''T. s. semipalmata'' <small>eastern willet</small>
* ''T. s. inornata'' <small>western willet</small>
| range_map = Tringa semipalmata map.svg
| range_map_caption = {{leftlegend|#FF7F2A|Breeding}}{{leftlegend|#5F8DD3|Nonbreeding}}
| synonyms = {{Specieslist
| Scolopax semipalmatus | J. F. Gmelin, 1789
| Symphemia semipalmata | (J. F. Gmelin, 1789)
| Catoptrophorus semipalmatus  | (J. F. Gmelin, 1789)
| Totanus semipalmatus | (J. F. Gmelin, 1789)
}}
| synonyms_ref = <ref name = Avibase>{{cite web |url=https://avibase.bsc-eoc.org/species.jsp?avibaseid=E7A14E91456CB432 |title=Willet ''Tringa semipalmata'' (Gmelin, JF 1789) |access-date=28 July 2025 |work=AviBase |publisher=Denis Lepage}}</ref>
}}

The '''willet''' ('''''Tringa semipalmata''''') is a large [[shorebird]] in the family [[Scolopacidae]]. It is a relatively large and robust [[sandpiper]] and is the largest of the species called "shanks" in the [[genus]] ''[[Tringa]]''. Its closest relative is the [[lesser yellowlegs]], a much smaller bird with a very different appearance apart from the fine, clear, and dense pattern of the neck, which both species show in breeding [[plumage]]. It breeds in North America and the West Indies and winters in southern North America, [[Central America]], the West Indies and South America.

==Taxonomy==
The willet was [[Species description|formally described]] in 1789 by the German naturalist [[Johann Friedrich Gmelin]] in his revised and expanded edition of [[Carl Linnaeus]]'s ''[[Systema Naturae]]''. He placed it in the [[genus]] ''[[Scolopax]]'' and coined the [[binomial nomenclature|binomial name]] ''Scolopax semipalmata''.<ref>{{ cite book | last=Gmelin | first=Johann Friedrich | author-link=Johann Friedrich Gmelin| year=1789 | title=Systema naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis | edition=13th | volume=1, Part 2 | language=Latin | location=Lipsiae [Leipzig] | publisher=Georg. Emanuel. Beer | page=659 | url=https://www.biodiversitylibrary.org/page/2656152 }}</ref> Gmelin based his description on the "semipalmated snipe" from New York that had been described in 1785 by both the English ornithologist [[John Latham (ornithologist)|John Latham]] and by the Welsh naturalist [[Thomas Pennant]].<ref>{{ cite book | last=Latham | first=John | author-link=John Latham (ornithologist) | year=1785 | title=A General Synopsis of Birds | volume=3, Part 1 | publisher=Printed for Leigh and Sotheby | location=London | page=152, No. 22 | url=https://www.biodiversitylibrary.org/page/40078917 }}</ref><ref>{{cite book | last=Pennant | first=Thomas | author-link=Thomas Pennant | year=1785 | title=Arctic Zoology | volume=2 | publisher=Printed by Henry Hughs | location=London | page=469, No. 380 | url=https://www.biodiversitylibrary.org/page/32122249 }}</ref> The willet was formerly assigned to the genus ''Catoptrosorus '' that had been introduced for the species in 1827 by [[Charles Lucien Bonaparte]].<ref>{{ cite journal | last=Bonaparte | first=Charles Lucien | author-link=Charles Lucien Bonaparte | year=1827 | title=The genera of North American birds, and a synopsis of the species found within the territory of the United States; systematically arranged in orders and families. Order IV. Grallae | journal=Annals of the Lyceum of Natural History of New York  | volume=2 | issue=1 | pages=293–432 [323] | doi=10.1111/j.1749-6632.1826.tb00254.x | url=https://www.biodiversitylibrary.org/page/15911384 }}</ref><ref>{{ cite book | editor-last=Peters | editor-first=James Lee | editor-link=James L. Peters | year=1934 | title=Check-List of Birds of the World | volume=2 | publisher=Harvard University Press | place=Cambridge, Massachusetts  | page=269 | url=https://www.biodiversitylibrary.org/page/14483082 }}</ref> In 2006 it was moved to the current genus ''[[Tringa]]'' based on a [[molecular phylogenetic]] study published the previous year.<ref>{{Cite journal | last1=Banks | first1=R.C. | last2=Cicero | first2=C. | last3=Dunn | first3=J.L. | last4=Kratter | first4=A.W. | last5=Rasmussen | first5=P.C. | last6=Remsen | first6=J.V. | last7=Rising | first7=J.D. | last8=Stotz | first8=D.F. | date=2006 | title=Forty-Seventh Supplement to the American Ornithologists' Union Check-List of North American Birds | journal=The Auk | volume=123 | issue=3 | pages=926–936 | doi=10.1093/auk/123.3.926 | doi-access=free}}</ref><ref>{{Cite journal | last1=Pereira | first1=Sérgio Luiz | last2=Baker | first2=Allan J. | date=2005 | title=Multiple gene evidence for parallel evolution and retention of ancestral morphological states in the shanks (Charadriiformes: Scolopacidae) | journal=The Condor | volume=107 | issue=3 | pages=514–526 | doi=10.1093/condor/107.3.514 | doi-access=free}}</ref> The genus name ''Tringa'' is the [[Neo-Latin]] word given to the [[green sandpiper]] by the Italian naturalist [[Ulisse Aldrovandi]] in 1603 based on [[Ancient Greek]] ''trungas'', a thrush-sized, white-rumped, tail-bobbing wading bird mentioned by [[Aristotle]]. The specific epithet ''semipalmata'' combines the [[Latin]] ''semi-'' meaning "half" or "small" with ''palmatus'' meaning "palmate".<ref>{{cite book | last=Jobling | first=James A. | year=2010| title=The Helm Dictionary of Scientific Bird Names | publisher=Christopher Helm | location=London | isbn=978-1-4081-2501-4 | pages=[https://archive.org/stream/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling#page/n390/mode/1up 390], [https://archive.org/stream/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling#page/n353/mode/1up 353]}}</ref>

Two subspecies are recognised:<ref name=ioc>{{cite web| editor1-last=Gill | editor1-first=Frank | editor1-link=Frank Gill (ornithologist) | editor2-last=Donsker | editor2-first=David | editor3-last=Rasmussen | editor3-first=Pamela | editor3-link=Pamela Rasmussen | date=August 2022 | title=Sandpipers, snipes, coursers | work=IOC World Bird List Version 12.2 | url=https://www.worldbirdnames.org/bow/sandpipers/ | publisher=International Ornithologists' Union | access-date=7 November 2022}}</ref>

*''T. s. inornata'' <small>([[William Brewster (ornithologist)|Brewster]], 1887)</small>: breeds from the [[Prairie Provinces]] of Canada south to northeastern [[California]], northern [[Colorado]] and western [[Nebraska]]; winters mainly on the Pacific coasts from the southern United States from coastal S USA to northern South America as far south as northern Chile. Some winter on the Atlantic coast southwards from the southern United States.<ref name = HBW>{{cite journal | url = http://www.hbw.com/species/willet-tringa-semipalmata | title = Willet (''Tringa semipalmata'') | access-date = 6 September 2017 | publisher = Lynx Edicions | journal = HBW Alive| date = 2020 | doi = 10.2173/bow.willet1.01 | last1 = Lowther | first1 = Peter E. | last2 = Douglas III | first2 = Hector D. | last3 = Gratto-Trevor | first3 = Cheri L. | editor-first1 = Alan F. | editor-first2 = Frank B. | editor-last1 = Poole | editor-last2 = Gill | url-access = subscription }}</ref> 
*''T. s. semipalmata'' <small>(Gmelin, 1789)</small>: breeds from southern [[Newfoundland]] and along the Atlantic coast of the United States into the [[Gulf of Mexico]], including the Caribbean Islands; winters in the West Indies and along the eastern coast of South America as far south as southern Brazil and Argentina. There are no documented records of this taxon wintering in the United States.<ref name = Birding>{{cite journal | author = Michael O'Brien | year = 2006 | title = Subspecific identification of Willets ''Catoptrophus semipalmatus'' | url = https://www.aba.org/birding/v38n3p40.pdf | journal = Birding | issue = May–June 2006 | pages = 40–47 | archive-date = 2012-10-19 | access-date = 2017-09-06 | archive-url = https://web.archive.org/web/20121019063010/http://aba.org/birding/v38n3p40.pdf | url-status = dead }}</ref>

It has been suggested that the two subspecies be treated as separate species as there are clear differences in distribution, behavior, morphology, and genetics, but this has yet to be widely adopted.<ref>{{Cite journal | last1=Oswald | first1=J.A. | last2=Harvey | first2=M.G. | last3=Remsen | first3=R.C. | last4=Foxworth | first4=D.U. | last5=Cardiff | first5=S.W. | last6=Dittmann | first6=D.L. | last7=Megna | first7=L.C. | last8=Carling | first8=M.D. | last9=Brumfield | first9=R.T. | date=2016 | title=Willet be one species or two? A genomic view of the evolutionary history of ''Tringa semipalmata'' | journal=The Auk | jstor=90009385 | volume=133 | issue=4 | pages=593–614 | doi=10.1642/AUK-15-232.1 | doi-access=free }}</ref>

The willet is a very rare [[Vagrancy (biology)|vagrant]] to Europe with records from the [[Azores]], mainland Portugal, France, Norway and Finland. The Portuguese record from [[Alcochete]] near [[Lisbon]] on 29 April 2009 showed characteristics of the eastern subspecies.<ref name = BoI>{{cite book | author1 = Eduardo de Juana | author2 = Ernest Garcia | year = 2015 | title = Birds of the Iberian Peninsula  | publisher = Christopher Helm | isbn = 978-1-4081-2480-2 | page = 317}}</ref>

==Description==
[[File:Tringa semipalmata-flapping.jpg|thumb|right|The white wing band is distinctive in flight, both above and below]]
The willet is an inelegant and heavily built shorebird with a structure similar to that of the [[common redshank]] but being larger in size than the [[greater yellowlegs]] while resembling a [[godwit]] in flight with black primary coverts and [[flight feather|primaries]] contrasting with a broad white band, white [[flight feather|secondaries]] with a white rump and gray tail band. With its reclassification into the ''Tringa'' genus, it stands as the largest species in this prominent sandpiper genus.<ref>{{cite book |title=CRC Handbook of Avian Body Masses |edition=2nd |editor-first=John B. Jr. |editor-last=Dunning |publisher=CRC Press |year=2008 |isbn=978-1-4200-6444-5}}</ref> It is {{cvt|31|-|41|cm}} in overall length and weighs {{cvt|200|-|330|g}}. The sexes are similar in plumage but the female is slightly larger.<ref name=bow>{{cite journal | last1=Lowther | first1=P.E. | last2=Douglas III | first2=H.D. | last3=Gratto-Trevor | first3=C.L. | year=2020 | title=Willet (''Tringa semipalmata''), version 1.0 | editor1-last=Poole | editor1-first=A.F. | editor2-last=Gill | editor2-first=F.B. | journal=Birds of the World | location=Ithaca, NY, USA | publisher=Cornell Lab of Ornithology | doi=10.2173/bow.willet1.01 }}</ref>

The black underwing coverts may be conspicuous in flight. Willets are identified on the ground by their gray legs and shortish, heavy but straight bill. The plumage is gray above with a white rump, and white below with a distinct white area above the [[Lore (anatomy)|lores]] and a narrow whitish eye ring giving the bird a spectacled appearance. The underparts are white. In breeding plumage, the bird shows brown barring on the upperparts. Non-breeding birds are plainer.{{cn|date=July 2025}}

===Voice===
The willet's name is onomatopoeic and refers to its loud piercing "''pill-will-willet''" territorial song.,<ref name = NHPTV/> which is higher pitched and repeated at a faster rate in Eastern willets than in Western birds.<ref name = Cornell/> Other calls include a predator response call given by breeding birds which is a repeated, staccato "''kleep''", while non breeding birds alarms include a high, pitched anxious "''kip-kip-viek''" call and a "''kreei''" call. They also have a distinctive call when crossing another willet's territory and this "''klay-dir''" call is also used as a contact call when willets are migrating.<ref name = Cornell/>

==Distribution and habitat==
Two subspecies (which may actually be different species)<ref>{{cite book |title=The Shorebird Guide |first1=Michael |last1=O'Brien |first2=Richard |last2=Crossley |first3=Kevin |last3=Karlson |year=2007 |publisher=Houghton Mifflin Harcourt |location=Boston |page=363 |isbn=978-0-618-43294-3}}</ref> have very different breeding habitats. The eastern willet breeds in coastal [[saltmarsh]]es while the western willet breeds in freshwater prairie marshes, sloughs, potholes and other inland wetlands. In winter both subspecies are coastal birds being found on both rocky and sandy coasts as well as on mudflats and in coastal marshes.<ref name = Cornell>{{cite web | url = https://www.allaboutbirds.org/guide/Willet/id | title = Willet | access-date = 6 September 2017 | publisher = Cornell University | author = The Cornell Lab of Ornithology | year = 2015}}</ref>

==Behavior and ecology==
They are territorial both on the breeding grounds and on the wintering areas but form loose breeding colonies or wintering groups. When displaying the wings are held stiffly and downcurved in flight while on the ground the display gives prominence to the distinctive pattern of the underwings. They are normally vigilant birds, with the birds closer to the landward edge of a saltmarsh being the first to utter their alarm calls, in a manner reminiscent of the [[common redshank]] in Europe, although some individuals may be approachable.<ref name =bow/>

===Food and feeding===
Willets are flexible in their feeding habits and hunt by walking steadily and pecking prey from the substrate, although they also probe into the mud or silt with their sensitive bill and may actively stalk larger prey in shallow water. A favored prey on the coasts is small [[fiddler crab]]s as well as [[mole crab]]s, worms, clams and other [[Invertebrate|invertebrates]].<ref>{{Cite web |title=Willet |url=https://www.audubon.org/field-guide/bird/willet |website=Audubon}}</ref>  They have also been known to occasionally eat plant material. Willets also actively hunt more mobile prey such as fish and aquatic insects in the water and will wade up to their bellies to pursue such prey. Prey recorded in western willets during breeding include water scavenger beetles ([[Hydrophilidae]]), diving beetles ([[Dytiscidae]]), snout beetles ([[Curculionidae]]), spiders ([[Spider|Araneae]]) and fish ([[Cypriniformes]]).<ref name="animaldiversity.org">{{cite web | url=https://animaldiversity.org/accounts/Catoptrophorus_semipalmatus/ | title=Catoptrophorus semipalmatus (Willet) | website=[[Animal Diversity Web]] }}</ref> In winter, western willets have been recorded eating shore crabs (''[[Hemigrapsus]]''), brachyuran crabs (''[[Uca]] princeps'', ''[[Leptuca crenulata]]''), crabs (''[[Pachygrapsus]]''), clams (''[[Macoma]]'', ''[[Gemma gemma]]''), nereid worms (''[[Neanthes (annelid)|Neanthes]]''), mussels (''[[Mytilus (bivalve)|Mytilus]]''), whelks ([[Nassariidae]]) and others.<ref name="animaldiversity.org"/> Eastern willets eat primarily marine coastal prey, including fiddler crabs (''[[Minuca minax]]'', ''[[Minuca pugnax]]'', ''[[Leptuca pugilator]]''), other crabs (''[[Armases cinereum]]'', ''[[Sesarma reticulatum]]''), mole crabs (''[[Emerita talpoida]]''), amphipods (''[[Corophium volutator]]'') and other marine invertebrates.<ref name="animaldiversity.org"/> The sensitive bill means that willets can hunt at night as well as during the day.<ref name = Cornell/><ref name="Hayman, Marchant and Prater">{{cite book|author1=Peter Hayman|title=Shorebirds: An identification guide to the waders of the World|author2=John Marchant|author3=Tony Prater|publisher=Croom Helm|year=1986|isbn=0-7099-2034-2|pages=331–332}}</ref><ref name = NHPTV>{{cite web | url = http://www.nhptv.org/natureworks/willet.htm | title = Willet - ''Catoptrophorus semipalmatus'' | access-date = 7 September 2017 | publisher = New Hampshire Public Television | work = Nature Works | year = 2017}}</ref> They often use rocks, trees or fence posts to perch on.<ref name = NHPTV/>

===Breeding===
[[File:Tringa semipalmata MHNT.ZOO.2010.11.147.6.jpg|upright=0.7|thumb|right|Egg]]
The male normally leads the female through the territory and creates trial nest scrapes for the female to consider until she selects the site. The nest is a shallow depression scraped out by the birds using their feet and breast, it measures 15&nbsp;cm across and 5&nbsp;cm deep. It is placed among grass close to the water's edge in western willets and in saltmarsh or sand dunes in eastern willets. If the nest is placed among grass the female may pull grass stalks over the nest for camouflage. Fine grass leaves and small pebbles may be used to line the nest and grass lining may be brought from some distance where the nest is on bare ground. The male and female may form a long-term monogamous bond and return to the same territory in successive breeding seasons. The male defends the territory from other willets, challenging his neighbors with a ritualized walk along the mutual boundary of their territory, and often this leads to fights. Both sexes incubate the eggs for 22–29 days, although the male tends to incubate at night, the female departs from the territory before the precocial young are fledged leaving them in the care of the male for the last two weeks or so before they fledge.<ref name = Cornell/><ref name = Howe>{{cite journal | author = Marshall A. Howe | year = 1982 | title = Social organization in a nesting population of eastern willets (''Catoptrophus semipalmatus'') | url = https://sora.unm.edu/sites/default/files/journals/auk/v099n01/p0088-p0102.pdf | journal = The Auk | volume = 99 | issue = January 1982 | pages = 88–102| doi = 10.2307/4086024 | jstor = 4086024 | bibcode = 1982Auk....99...88H }}</ref><ref name = NHPTV/>

==Conservation==
The willet is still common in some parts of its range despite an apparent decline since the 1960s. It is also considered to be a species at risk of becoming threatened or endangered without conservation action. The western subspecies is threatened by the conversion of native grasslands and drainage of wetlands for agriculture while the wintering habitat has been degraded locally in California by coastal development. Willets are also vulnerable to being killed by colliding with power lines laid through their wetland breeding areas. The passage of the Migratory Bird Treaty Act in 1918 protected the willet from intensive exploitation by hunters for food and allowed its numbers to rebound to present levels.<ref name = Cornell/> There are a total of 250,000 willets in North America, of which 150,000 were counted from the western flyway, and 90,000 in the eastern. Since the Western willet winters in the east, that means that there are probably much less than 90,000 Eastern willets.<ref name = Birding/>

==Gallery==
<gallery widths="200px" heights="160px">
Willet (Tringa semipalmata) RWD4.jpg|Breeding plumage, North Carolina
Willet feeding.jpg|After catching a fish in [[Manuel Antonio National Park]], Costa Rica
Willet 2.jpg|Willet, North Carolina
File:20250706 willet sandy point bird sanctuary PD208009.jpg|In flight, showing the bold underwing pattern
Tringa semipalmata (Willet) 1APR2017.jpg|Bodega Bay, California. April 2017.
Willet-16SEP2017.jpg|Foster City, California. September 2017.
</gallery>

==References==
{{Reflist}}

{{Scolopacidae|2}}
{{Taxonbar|from=Q831611}}

[[Category:Birds described in 1789]]
[[Category:Birds of Puerto Rico]]
[[Category:Birds of the Dominican Republic]]
[[Category:Birds of the United States]]
[[Category:Fauna of the Plains-Midwest (United States)]]
[[Category:Shorebirds]]
[[Category:Taxa named by Johann Friedrich Gmelin]]
[[Category:Tringa]]
[[Category:Least concern biota of the United States]]