Thesuperciliumis aplumagefeature found on the heads of somebirdspecies. It is a stripe which runs from the base of the bird'sbeakabove its eye, finishing somewhere towards the rear of the bird's head.[1]Also known as an "eyebrow",[1]it is distinct from theeyestripe,which is a line that runs across thelores,and continues behind the eye.[2]Where a stripe is present only above the lores, and does not continue behind the eye, it is called asupraloral stripeor simplysupraloral.[1]On most species which display a supercilium, it is paler than the adjacentfeather tracts.[3]
The colour, shape or other features of the supercilium can be useful in bird identification. For example, the supercilium of thedusky warbler,anOld World warblerspecies, can be used to distinguish it from the very similarRadde's warbler.The dusky warbler's supercilium is sharply demarcated, whitish and narrow in front of the eye, becoming broader and more buffy towards the rear, whereas that of the Radde's warbler is diffusely defined, yellowish and broadest in front of the eye, becoming narrower and more whitish toward the rear.[4]The supercilium of thenorthern waterthrush,aNew World warbler,differs subtly from that of the closely related (and similarly plumaged)Louisiana waterthrush.The Louisiana has a bicoloured supercilium which widens significantly behind the eye, while the northern has an evenly buffy eyebrow which is either the same width throughout or slightly narrower behind the eye.[5]
Asplit superciliumdivides above the lores. In some species, such as thejack snipe,the divided stripes reconnect again behind the eye.[6]In others, such as thebroad-billed sandpiper,the divided stripes remain separate.[7]
Asupercilium dropis a feature found on somepipits;[8]it is a pale spot on the rear of theear-covertswhich, although separated from the supercilium by an eyestripe, can appear at some angles to be a downward continuation of the supercilium.
Gallery
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TheCanada warblershows a yellow supraloral. -
Thebroad-billed sandpiperhas a split supercilium... -
...as does thejack snipe. -
The olive-backed pipit has a supercilium drop.
References
editNotes
edit- ^abcDunn and Alderfer (2006), p. 10
- ^Dunn and Alderfer (2006), p. 11
- ^Kaufman, Kenn (2011) A Field Guide to Advanced BirdingISBN978-0-547-24832-5,page 51
- ^Mullarney, Killian; Svensson, Lars; Zetterström, Dan; Grant, Peter J (1999).Collins Bird Guide.London: HarperCollins. pp. 306–307.ISBN0-00-219728-6.
- ^Dunn and Alderfer (2006), p. 394.
- ^Hayman, Marchant and Prater (1986), p. 359
- ^Hayman, Marchant and Prater (1986), p. 383
- ^Harris, Alan; Tucker, Laurel; Vinicombe, Keith (1989).The MacMillan Field Guide to Bird Identification.Grange Books. p. 158.ISBN1-85627-641-4.
Sources
edit- Dunn, Jon L.; Alderfer, Jonathan, eds. (2006).Field Guide to the Birds of North America.Washington, D.C.: National Geographic Society.ISBN0-7922-5314-0.
- Hayman, Peter; Marchant, John; Prater, Tony (1986).Shorebirds.Breckenham, UK: Croom Helm.ISBN0-7099-2034-2.