It has been suggested that discrimination and rejection of the nestlings of avian brood parasites are most likely to evolve when the parasite nestling is raised alongside the host nestlings, for example, many cowbird-host systems. Under these circumstances, the benefits of discrimination are...

Carotenoid-based plumage ornaments are typically considered to be sexually selected traits, functioning as honest condition-dependent signals of phenotypic quality, but few studies have addressed the function of carotenoid color variation in male contest competition. Using two experiments, we...