Ecology and evolution of extravagant feather ornaments

The ancestral conditions that permit the evolution of extravagant secondary sexual characters are of considerable theoretical and empirical interest b ecause they allow identification of necessary ecological conditions, but al so allow empirical tests of models of female mate preferences. We investiga ted the ancestral and derived state of a range of ecological and evolutiona ry variables that might have been implicated in the evolution of secondary sexual characters. Extravagant feather ornaments have evolved independently at least 70 times in birds, and the context of these evolutionary events w as investigated statistically. The acquisition of feather ornaments was sig nificantly associated with a change in social mating system from monogamy t o polygyny or lekking. This association is consistent with the Fisherian me chanism of sexual selection. However, very often also the acquisition of fe ather ornaments occurred without change in mating system. Therefore, orname ntation can develop for reasons other than polygyny. We did not find any in dication of male parental care, kind of food, foraging mode, coloniality, n est site, migration or body mass being significantly associated with a chan ge in the state of ornamentation.