Plumage variation and dominance in captive female Red-winged Blackbirds

Abstract

Flocks of female Red-winged Blackbirds (Agelaius phoeniceus) were maintained in aviaries to determine whether variation in brightness of epaulette or chin plumage correlated with dominance status in nonbreeding situations. No correlation was found between natural plumage variation and dominance in eight control groups, although dominant females were heavier and in better condition. In two groups in which epaulettes were experimentally brightened on some birds and two groups where some chins were brightened, brightening an individual's plumage had no consistent effect on dominance status. Thus, we did not find any evidence that there is direct selection on female plumage brightness for signalling competitive ability outside the breeding season. We propose that bright plumage in females could be an indirect consequence of genetic correlation with a trait selected for in males.