Paternal care as a conditional strategy: distinct reproductive tactics associated with elaboration of plumage ornamentation in the house finch

When individuals in a population differ in physiological condition and residual reproductive value, selection should favor phenotypic plasticity in reproductive investment such that individuals are able to adopt the reproductive tactic that results in the highest fitness under given conditions. Here we examined reproductive tactics in relation to the elaboration of condition-dependent sexual ornamentation (carotenoid breast coloration) in a Montana population of the house finches (Carpodacus mexicanus). Males used distinct reproductive tactics depending on elaboration of their sexual ornamentation. Males with red pigmentation (maximum ornament elaboration) paired with females that nested earlier, but these males did little provisioning of incubating females and nestlings. In contrast, males with yellow coloration paired with females that nested later, but these males fed female and nestlings more. Consequently, for red males offspring recruitment was primarily affected by earlier nest initiation, whereas in yellow males it was affected most by male provisioning. In males with intermediate plumage coloration, all measured components, nest initiation, provisioning of incubating female, and nestling feeding, strongly contributed to offspring recruitment. The fitness consequences of alternative reproductive tactics of males were influenced by breeding experience and fidelity of their mates. Among first-time breeders, red males achieved the highest fecundity because of the advantage gained through early nesting and pairing with more experienced females and because of compensation by their mates for low male provisioning of nestlings. Among experienced breeders, males with intermediate plumage coloration achieved the highest fecundity because of the combined benefits of relatively early pairing and high parental care. High variation in sexual ornamentation in a Montana population of house finches may favor distinct associations of sexual displays with a particular set of reproductive behaviors. Copyright 2002.