Great knot

{{Short description|Species of bird}} {{For|the fell in Cumbria, England|Crinkle Crags}} __NOTOC__ {{Speciesbox | image = Calidris tenuirostris, Nadezhdinsky, Primorsky Krai, Russia 1 (crop).jpg | image_caption = Breeding plumage, Primorsky Krai, Russia | image2 = Calidris tenuirostris - Laem Phak Bia.jpg | image2_caption = Winter plumage, Thailand | status = EN | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{cite iucn |author1=BirdLife International |year=2025 |title=''Calidris tenuirostris'' |article-number=e.T22693359A254641184 |doi=10.2305/IUCN.UK.2025-2.RLTS.T22693359A254641184.en}}</ref> | status2 = CR | status2_system = EPBC | status2_ref = <ref name=sprat/> | genus = Calidris | species = tenuirostris | authority = (Horsfield, 1821) }}

The '''great knot''' ('''''Calidris tenuirostris''''') is a medium-sized wader. It is one of the largest species in the genus ''Calidris''. It is a migratory bird which breeds in eastern Siberia, Russia, and flies to southern Asia and Australia in the northern winter.

==Taxonomy== Within the genus ''Calidris'' the great knot is most closely related to the surfbird (''Calidris virgata'').<ref>{{cite journal | last1=Černý | first1=David | last2=Natale | first2=Rossy | date=2022 | title=Comprehensive taxon sampling and vetted fossils help clarify the time tree of shorebirds (Aves, Charadriiformes) | journal=Molecular Phylogenetics and Evolution | volume=177 | article-number=107620 | doi=10.1016/j.ympev.2022.107620|url=https://www.biorxiv.org/content/biorxiv/early/2021/07/16/2021.07.15.452585.full.pdf }}</ref>

The genus name is from Ancient Greek ''kalidris'' or ''skalidris'', a term used by Aristotle for some grey-coloured waterside birds. The specific '' tenuirostris '' is from Latin ''tenuis'' "slender" and ''rostrum'' "bill".<ref name=job>{{cite book | last= Jobling | first= James A | year= 2010| title= The Helm Dictionary of Scientific Bird Names | url= https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling | publisher=Christopher Helm | location = London | isbn = 978-1-4081-2501-4 | pages=84, 381}}</ref>

==Distribution== Their breeding habitat is tundra in northeast Siberia, Russia. They nest on the ground laying about four eggs in a ground scrape. They are strongly migratory wintering on coasts in southern Asia through to Australia. This species forms enormous flocks in winter.

The species is also recorded in summer in low numbers in western Alaska, United States in most years, and in winter in small numbers west to Pakistan, Oman, and the United Arab Emirates.<ref name="Lewington">{{cite book | last1=Lewington | first1=Ian | last2=Alström | first2=Per | last3=Colston | first3=Peter | title=A Field Guide to the Rare Birds of Britain and Europe | publisher=HarperCollins | date=1991 | isbn=0-00-219917-3 | pages=115–116}}</ref> It has occurred as a vagrant in Great Britain, Morocco,<ref name="Lewington"/> New Zealand, British Columbia in Canada, and in the lower 48 states of the USA in Oregon, West Virginia, and Maine.

''Calidris tenuirostris'', commonly known as the great knot, is one of the largest species of the genus ''Calidris'', in the family Scolopacidae. The ruff ''C. pugnax'', with its marked sexual dimorphism in size, can have larger males, but its females are much smaller. Its sister species, the surfbird ''C. virgata'' and red knot ''C. canutus'', are the next largest. Adult great knots can measure {{convert|26|to|30|cm|in|abbr=on}}, with a wingspan of {{convert|56|to|66|cm|in|abbr=on}}, and weighing {{convert|115|to|261|g|oz|abbr=on}}.<ref>Jeyarajasingam, A. (2012). ''A field guide to the birds of Peninsular Malaysia and Singapore''. Oxford University Press.{{page needed|date=September 2024}}</ref><ref>Van Gils, J., P. Wiersma, G. M. Kirwan, and C. J. Sharpe (2020). "Great Knot (''Calidris tenuirostris''), version 1.0". In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref><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}}{{page needed|date=September 2024}}</ref>

This species has short dark legs and a medium-length thin dark bill. Breeding adults have mottled greyish upper parts, with a distinct band of rufous feathering on the scapular feathers. The face, throat and breast are heavily spotted black, and there are also some streaks on the rear belly. In winter the plumage becomes uniformly pale grey above.

It is distinguished from the red knot by its breeding plumage, in which the latter has a distinctive red face, throat and breast. In other plumages, the great knot can be identified by its larger size, longer bill, deeper chest, and the more streaked upper parts.

==Behaviour== These birds forage on mudflats and beaches, probing or picking up food by sight. They mainly eat molluscs and insects.

== Conservation status == The great knot is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

=== Australia === Since 5 May 2016 and {{as of|lc=yes|August 2023}}, the great knot is listed as critically endangered in Australia under the federal ''Environment Protection and Biodiversity Conservation Act 1999'' (EPBC Act), with the next assessment due on 30 October 2023.<ref name=sprat>{{cite web | title=''Calidris tenuirostris''—Great Knot | website=Species Profile and Threats Database |publisher= Department of Climate Change, Energy, the Environment and Water, Australian Government| date=2023 | url=http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=862 | access-date=23 August 2023| archive-date=23 August 2023| url-status=live| archive-url= https://web.archive.org/web/20230823122642/http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=862}} 50px Text may have been copied from this source, which is available under a [https://creativecommons.org/licenses/by/3.0/au/ Attribution 3.0 Australia (CC BY 3.0 AU)] licence.</ref> A study published in ''Biological Conservation'' in March 2023 listed 23 species which the authors considered to no longer meet the criteria as threatened species under the EPBC Act, including the great knot. The reason for the assessment was "Populations now stable or declining at a rate less than threshold".<ref name=woinarski2023>{{cite journal | last1=Woinarski | first1=John C.Z. | last2=Garnett | first2=Stephen T. | last3=Gillespie | first3=Graeme | last4=Legge | first4=Sarah M. | last5=Lintermans | first5=Mark | last6=Rumpff | first6=Libby|display-authors=2 | title=Lights at the end of the tunnel: The incidence and characteristics of recovery for Australian threatened animals | journal=Biological Conservation | publisher=Elsevier BV | volume=279 | year=2023 | issn=0006-3207 | doi=10.1016/j.biocon.2023.109946 | article-number=109946| doi-access=free | bibcode=2023BCons.27909946W }}</ref><ref>{{cite web | title=Researchers find 26 Australian species recovered from the brink of extinction | website=ABC News | date=24 February 2023 | url=https://www.abc.net.au/news/2023-02-24/australian-animals-no-longer-meet-criteria-as-threatened-species/102020276 | access-date=23 August 2023}}</ref>

Under state and territory legislation, the species is {{as of|lc=yes|August 2023}} listed as vulnerable in New South Wales and the Northern Territory; endangered in South Australia; and critically endangered in Queensland, Victoria, and Western Australia.<ref name=sprat/>

==References== {{Reflist}}

== External links == {{Commons category}} {{Wikispecies|Calidris tenuirostris}} * [https://www.oiseaux.net/birds/photos/great.knot.html Great knot] – Photos on Oiseaux.net

Category:Articles containing video clips Category:Birds described in 1821 Category:Birds of North Asia Category:Calidris Category:Taxa named by Thomas Horsfield Category:Wading birds