Date of Award:
5-1-2000
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Biology
Committee Chair(s)
James A. Gessaman
Committee
James A. Gessaman
Committee
Edmund D. Brodie Jr.
Committee
Martyn M. Caldwell
Abstract
If a species of birds is monomorphic, how do individuals identify members of the opposite sex? Birds may use cues in the ultraviolet wavelengths (350-400 nm), which are invisible to humans. This thesis presents evidence of sexual dichromatism in Bohemian Waxwings (Bombycilla garrulus). The strongest differences occurred in the tail coverts, the yellow tail tips, and the red waxy tips of the secondaries. Like other birds, waxwings derive colors from diet-based pigments and from synthesized colors. Because these color types differ in origin, each could provide different visual information about a bird's condition. This led to the testing of four predictions of waxwing coloration. The only prediction not supported by the results was the prediction that carotenoid colors would no be dichromic. It remains to be shown that waxwings are visually sensitive to the degree of dichromatism shown here and what, if any, information is given by their plumage coloration.
Recommended Citation
Burns, James Brian, "Sexual Dichromatism in Bohemian Waxwings" (2000). Biology. 670.
https://digitalcommons.usu.edu/etd_biology/670
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