Calidris Explained

Calidris is a genus of Arctic-breeding, strongly migratory wading birds in the family Scolopacidae. These birds form huge mixed flocks on coasts and estuaries in winter. They are small to medium-sized sandpipers, long-winged and relatively short-billed; some are difficult to identify because of the similarity between species, and various breeding, non-breeding, juvenile, and moulting plumages. With a few exceptions, they have a fairly stereotypical colour pattern, being brownish above and lighter, usually white or buffy coloured, on much of the underside. They often have a lighter supercilium above brownish cheeks.[1] The species are variously known in English as sandpipers or (particularly the smaller species) stints; some have their own unique names, with dunlin (a mediaeval name meaning "[small] brown bird"), knot (imitative of its call), ruff (named after its male display plumage), and sanderling and surfbird (named after their habitat and behaviour).[2] In North America, the smaller species are often known colloquially as peeps.

Their bills are flexible, able to exhibit rhynchokinesis,[3] and have sensitive tips which contain numerous corpuscles of Herbst. This enables the birds to locate buried prey items, which they typically seek with restless running and probing.[4] Migratory shorebirds are shown to have declined in reproductive traits because of temporal changes of their breeding seasons.[5]

Taxonomy

The genus Calidris was introduced in 1804 by the German naturalist Blasius Merrem with the red knot as the type species.[6] [7] The genus name is from Ancient Greek kalidris or skalidris, a term used by Aristotle for an unidentified grey-coloured waterside bird.[8]

Many of the species have been treated under other generic names at various times in the past, but these treatments leave Calidris polyphyletic;[9] [10] [11] synonyms are in brackets in the list below.

The genus contain 24 species:[12]

The following species-level cladogram is based on a molecular phylogenetic study by David Černý and Rossy Natale that was published in 2022. Some of the nodes are only weakly supported by the sequence data.[11]

Hybrids

Several hybrids have been discovered between different species in the genus. See Hybridisation in shorebirds for further details.

Notes and References

  1. Book: Hayman . Peter . Marchant . John . Prater . Tony . Shorebirds . Croom Helm . London . 1986 . 0-7099-2034-2 . 182–209, 363–387.
  2. Book: Lockwood, William Burley . The Oxford Book of British Bird Names . Oxford University Press, USA . Oxford ; New York . 1984 . 0-19-214155-4 . 55, 92, 132, 133, 147.
  3. Estrella . Sora M. . Masero . José A. . The use of distal rhynchokinesis by birds feeding in water . Journal of Experimental Biology . 210 . 21 . 2007-11-01 . 1477-9145 . 10.1242/jeb.007690 . 3757–3762 . 2026-02-24.
  4. Nebel, S.. Jackson, D.L.. Elner, R.W.. Functional association of bill morphology and foraging behaviour in calidrid sandpipers. 10.1163/1570756054472818. 2005. Animal Biology. 55. 3. 235–243. 2016-06-03. https://web.archive.org/web/20110610081512/http://publish.uwo.ca/~snebel2/nebel05AnimBiol.pdf. 2011-06-10. dead.
  5. Weiser . Emily L. . Brown . Stephen C. . Lanctot . Richard B. . Gates . H. River . Abraham . Kenneth F. . Bentzen . Rebecca L. . Bêty . Joël . Boldenow . Megan L. . Brook . Rodney W. . Donnelly . Tyrone F. . English . Willow B. . Flemming . Scott A. . Franks . Samantha E. . Gilchrist . H. Grant . Giroux . Marie-Andrée . February 2018 . Life-history tradeoffs revealed by seasonal declines in reproductive traits of Arctic-breeding shorebirds . Journal of Avian Biology . en . 49 . 2 . 1 . 10.1111/jav.01531 . 2018JAvBi..49....1W . 0908-8857. subscription .
  6. Merrem . Blasius . Blasius Merrem . 8 June 1804 . Naturgeschichte . German . Allgemeine Literatur-Zeitung . 168 . Col. 542 . Published anonymously.
  7. Book: Peters . James Lee . James L. Peters . 1934 . Check-List of Birds of the World . 2 . Harvard University Press . Cambridge, Massachusetts . 280 .
  8. Book: Jobling, James A . 2010. The Helm Dictionary of Scientific Bird Names . Christopher Helm . London . 978-1-4081-2501-4 . 84.
  9. Thomas . Gavin H . Wills . Matthew A . Székely . Tamás . A supertree approach to shorebird phylogeny . BMC Evolutionary Biology . 4 . 1 . 2004-08-24 . 1471-2148 . 15329156 . 515296 . 10.1186/1471-2148-4-28 . free .
  10. Gibson . Rosemary . Baker . Allan . Multiple gene sequences resolve phylogenetic relationships in the shorebird suborder Scolopaci (Aves: Charadriiformes) . Molecular Phylogenetics and Evolution . 64 . 1 . 2012 . 10.1016/j.ympev.2012.03.008 . 66–72 . 2025-09-12. subscription .
  11. Černý . David . Natale . Rossy . 2022 . Comprehensive taxon sampling and vetted fossils help clarify the time tree of shorebirds (Aves, Charadriiformes) . Molecular Phylogenetics and Evolution . 177 . 107620 . 10.1016/j.ympev.2022.107620. 36038056 . 2022MolPE.17707620C .
  12. Web site: AviList Core Team . 2025 . AviList: The Global Avian Checklist, v2025 . 10.2173/avilist.v2025 . free . 2026-02-24 .

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