Interest in female ornamentation has burgeoned recently, and evidence suggests that carotenoid-based female coloration may function as a mate-choice signal. However, the possibility that females may signal status with coloration has been all but ignored. Bill coloration of female American...

Sexual displays are typically given in the absence of predators. One possible exception to this is seen in male splendid fairy-wrens (Malurus splendens), which sing display-like vocalizations (Type II song) in response to predator calls. In this study, we explored the function of this vocal...

We examined the relationship between singing and reproductive success in cowbirds. We amassed data from 17 captive flocks (164 males, 167 females) that we have studied over 4 years. For each flock, we conducted extensive observations on social interactions as the birds competed, courted, and...

Organisms exhibiting genetic polymorphism often also exhibit true alternative life-history strategies in which behavioral tactics are genetically fixed. Such systems are ideal for the study of the evolution of life histories because the consequences of selective episodes can be more easily...

Males of many species can breed in distinct alternative phenotypes; for example, in many birds some males breed in dull plumage while others breed in bright plumage. Because females often appear to prefer brighter males, it is unclear why some males breed in dull plumage. Males in dull plumage...

The occurrence of multiple phenotypes within a sex of a single species has long puzzled behavioral ecologists. Male red-backed fairy-wrens Malurus melanocephalus exhibit 3 behaviorally distinct types in their first breeding season: breed in bright nuptial plumage, breed in dull plumage, or...

Theoretical models suggest that males should adjust their parental effort according to paternity when parental effort is costly, paternity varies among clutches, and males have a cue to assess paternity. To date, nearly all tests of this theory have been conducted using birds as model organisms....