Term of Award
Master of Science in Biology (M.S.)
Document Type and Release Option
Thesis (open access)
Department of Biology
C. Ray Chandler
Committee Member 1
Committee Member 2
Bright plumage coloration in most birds is thought to be a product of sexual selection. Brighter, more-ornamented males are preferred by females because their plumage conveys information regarding the quality of the individual. One measure of male quality is willingness to invest in offspring. In birds, investment is usually measured as the rate at which nestlings are provisioned. However there are other forms of parental investment. The purpose of this study is to quantify the relationship between two measures of parental investment and their association with structural plumage coloration in male Eastern Bluebirds (Sialia sialis). I found there was no correlation between nestling provisioning and nest defense for males or females. Males with brighter UVblue plumage tend to provision nestlings at higher rates and more-ornamented males tend to defend the nest from a predator at lower rates. This study suggests that structural coloration is an indicator of the ability of a male to invest in its young. However, because nestling provisioning and nest defense (the two main male parental investments) were not correlated, I suggest that nestling provisioning and nest defense are not equivalent measures of parental investment, and condition-dependent traits have different relationships to different measures of parental investment.
Wetzel, Daniel Paul, "Parental Investment and Male Ornamentation in the Eastern Bluebird (Sialis Sialis)" (2006). Electronic Theses & Dissertations. 711.