Supercilium

A Whinchat has a prominent white supercilium

The term supercilium is a name for a plumage feature present on the heads of many bird species. It is a stripe which starts above the bird's loral area, continuing above the eye, and finishing somewhere towards the rear of the bird's head. It is distinct from the eyestripe which is a line which runs across the lores, and continues behind the eye. Informally, the supercilium is often known as the "eyebrow". Where a stripe is present only above the lores, and does not continue behind the eye, it is called a supraloral stripe or simply supraloral.

On most species which display a supercilium, it is paler than the adjacent feather tracts.

The colour, shape or other features of the supercilium can be useful in bird identification. For example, one way to tell Dusky and Radde's Warblers apart is to look at their supercilium. On Dusky it is sharply demarcated in front of the eye, a bright cream colour here, but becoming duller to the rear, whereas on Radde's, it is loosely-demarcated in front of the eye, buff-orange here and bright to the rear.

A split supercilium is a feature present on some shorebirds (e.g. Broad-billed Sandpiper). This term is used to describe a plumage pattern where the supercilium has an extra stripe branching off it above the lores, and extending up into the crown.

A supercilium drop is a feature found on some pipits; it is a pale spot on the rear of the ear-coverts which, although separated from the supercilium by an eyestripe, can appear at some angles to be a downward continuation of the supercilium.

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