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| | Eye Color and Development (Site not responding. Last check: 2007-10-30) |
 | | In many species, eye color changes as the bird matures and can serve as a means of determining an individual's age. |
 | | Although the physiology of iris pigmentation is poorly understood, changes in color with age and with season are likely to be under hormonal control, especially where colors are closely associated with the sexual cycle. |
 | | Changes of eye color with age are found in a wide variety of avian families including the loons, grebes, ducks, hawks, pheasants, gulls, alcids, woodpeckers, mimic thrushes, vireos, and flbirds. |
| www.stanford.edu /group/stanfordbirds/text/essays/Eye_Color.html (288 words) |
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