In numerous avian species, males and females display ornaments that could act as signals in interactions with conspecifics. Much of the research on these ornaments has focused on mutual mate choice and intrasexual competition between males. However, few studies have examined female and male ornamentation simultaneously in the context of intrasexual competition and the acquisition of breeding resources. I examined whether plumage coloration of male and female Prothonotary Warblers (Protonotaria citrea) was related to the quality of their nest site by placing nest boxes in preferred locations over deep water and at less preferred sites over land. Age and body size were not related to the ability of males or females to obtain a nest site over deep water. Males that were brighter yellow and more pure yellow obtained boxes over deep water, and older females that were more pure yellow did as well. However, in an analysis that included young and old females, I found no relationship between plumage coloration and nest-box quality. These results indicate that coloration could be a signal of competitive ability, particularly in males.