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The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. [1] Also known as an "eyebrow", [1] it is distinct from the eyestripe, which is a line that runs across the lores, and continues behind ...
Most birds moult twice a year, resulting in a breeding or nuptial plumage and a basic plumage. Many ducks and some other species such as the red junglefowl have males wearing a bright nuptial plumage while breeding and a drab eclipse plumage for some months afterward.
External anatomy of a typical bird: 1 Beak, 2 Head, 3 Iris, 4 Pupil, 5 Mantle, 6 Lesser coverts, 7 Scapulars, 8 Coverts, 9 Tertials, 10 Rump, 11 Primaries, 12 Vent, 13 Thigh, 14 Tibio-tarsal articulation, 15 Tarsus, 16 Feet, 17 Tibia, 18 Belly, 19 Flanks, 20 Breast, 21 Throat, 22 Wattle, 23 Eyestripe Topography of a typical passerine.
In some birds, a partial molt occurs before the bird breeds. This plumage is known as the alternate plumage and is generally what was previously known as a bird's breeding plumage. If a bird produces a third plumage in addition to the basic and alternative, it is known as supplemental plumage. This plumage is most frequently found in ptarmigans ...
The position of the nest and whether it has a greater chance of being under predation has exerted constraints on female birds' plumage. [47] A species of bird that nests on the ground, rather than the canopy of the trees, will need to have much duller colors in order not to attract attention to the nest. The height study found that birds that ...
A visible ring of feathers around a bird's eye; the eye-ring is often paler than the surrounding feathers. By contrast, an orbital ring is bare skin ringing the eye. In some species, such as little ringed plover, the orbital ring may be quite conspicuous. [97] eyestripe Also, eye line / eyeline.
Birds have a number of adaptations which give visual acuity superior to that of other vertebrate groups; a pigeon has been described as "two eyes with wings". [1] Birds are theropods, [2] [3] and the avian eye resembles that of other sauropsids, with ciliary muscles that can change the shape of the lens rapidly and to a greater extent than in ...
The black-necked grebe or eared grebe (Podiceps nigricollis) is a member of the grebe family of water birds. It was described in 1831 by Christian Ludwig Brehm.Its breeding plumage features distinctive ochre-coloured feathers which extend behind its eye and over its ear coverts.