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The eye-ring of a bird is a ring of tiny feathers that surrounds the orbital ring, a ring of bare skin immediately surrounding a bird's eye. The eye-ring is often decorative, and its colour may contrast with adjoining plumage. The ring of feathers is sometimes incomplete, forming an eye arc. In the absence of a conspicuous eye-ring, the orbital ring of a bird is often referred to as the eye-ring.
The bare orbital ring may be hardened or fleshy, or may form an eye- wattle. These are useful field marks in many bird species, and the eye-ringed flatbill, eye-ringed tody-tyrant and eye-ringed thistletail are examples of species named for either of these. __NOTOC__
File:Cossypha caffra, juveniel, Pretoria, h.jpg,
The eye-ring of a bird is a ring of tiny feathers that surrounds the orbital ring, a ring of bare skin immediately surrounding a bird's eye. The eye-ring is often decorative, and its colour may contrast with adjoining plumage. The ring of feathers is sometimes incomplete, forming an eye arc. In the absence of a conspicuous eye-ring, the orbital ring of a bird is often referred to as the eye-ring.
The bare orbital ring may be hardened or fleshy, or may form an eye- wattle. These are useful field marks in many bird species, and the eye-ringed flatbill, eye-ringed tody-tyrant and eye-ringed thistletail are examples of species named for either of these. __NOTOC__
Function
Eye-rings are believed to convey various types of signals between individual birds. Some eye-rings appear only atsexual maturity
Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definit ...
, while others suggest the individual's age or health status. Individual birds may be included or excluded from reproductive capability due to signals conveyed by the eye-ring. Red carotenoid
Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, ...
-based colors of the orbital rings of pheasants are known to be related to health.
The function of the white eye-rings in white-eyes is unknown. It is suspected that they may serve to highlight infestations of small ectoparasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...
s around the eyes. Untainted white eye-rings may consequently express vigorous health. In addition they may signal membership of a particular group or population, as different species and populations may have rings of differing colour, size, shape or completeness. These recognition signals could then play a role in reproductive isolation
The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offsprin ...
and speciation
Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution withi ...
.
Gallery
Robin-chat Robin-chat is a name given to a number of bird species:
* '' Cossypha''
* ''Cossyphicula'', also named the White-bellied robin-chat
{{Short pages monitor
Birds by common name ...
species, with a double ring of small feathers about the eye
File:Geothlypis tolmiei Hungry Horse MT 1, crop.jpg, Eye arcs above and below the eye of a male MacGillivray's warbler
MacGillivray's warbler (''Geothlypis tolmiei'') is a species of New World warbler. These birds are sluggish and heavy warblers, preferring to spend most of their time on, or near the ground, except when singing.
left, A MacGillivray's warbler p ...
File:Glareola maldivarum - Beung Borapet, crop.jpg, Pratincole with a complete but partially contrasting eye-ring
File:Killdeer and child, crop.JPG, The killdeer
The killdeer (''Charadrius vociferus'') is a large plover found in the Americas. It was described and given its current scientific name in 1758 by Carl Linnaeus in the 10th edition of his ''Systema Naturae''. Three subspecies are described. Th ...
, one of many wader
245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots
Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
s with a conspicuous orbital ring
File:Anser erythropus -WWT Slimbridge, Gloucestershire, England -head-8a, crop.jpg, Bright yellow orbital ring in a lesser white-fronted goose
The lesser white-fronted goose (''Anser erythropus'') is a goose closely related to the larger white-fronted goose (''A. albifrons''). It breeds in the northernmost Palearctic, but it is a scarce breeder in Europe. There is a re-introduction s ...
File:Blackbird (Turdus merula) ♂ (51015122728).jpg, A male blackbird with distinct orbital ring
See also
*Glossary of bird terms
The following is a glossary of common English language terms used in the description of birds—warm-blooded vertebrates of the class Aves and the only living dinosaurs, characterized by , the ability to in all but the approximately 60 extant ...
* Iris
Iris most often refers to:
*Iris (anatomy), part of the eye
*Iris (mythology), a Greek goddess
* ''Iris'' (plant), a genus of flowering plants
* Iris (color), an ambiguous color term
Iris or IRIS may also refer to:
Arts and media
Fictional ent ...
* List of terms used in bird topography
The following is a list of terms used in bird topography:
Plumage features
* Back
* Belly
* Breast
* Cheek
* Chin
* Crest
* Crown
* Crown patch
* Ear-coverts
* Eye-ring
* Eyestripe (or eye line)
* Feather, see category: :Feathers
* Fla ...
* Sclerotic eye-ring
References
{{Feather-tracts Bird anatomy Feathers