Female quail prefer testosterone-mediated traits, rather than the ornate plumage of males

The New World quail belong to the avian order Galliformes, in which plumage dichromatism is oestrogen based; oestrogen induces the expression of female-like plumage. We examined female mate choice in two congeneric species of New World quail, Gambel's quail, Callipepla gambelii, a highly ornate and dichromatic species, and scaled quail, C. squamata, a monochromatic species, to determine the kinds of male traits involved in female mate choice. In trials of unmanipulated males, as well as trials involving manipulations of single and multiple feather ornaments, female choice was not related to male plumage. Rather, in both species, females preferred high rates of male courtship. We predictably manipulated female mating decisions by presenting males that displayed at different rates. In scaled quail only, female choice also correlated with males of larger size. Consistent with studies of other galliform species, male plumage is not a primary means by which female quail make mating decisions. Instead, females appear to favour traits capable of signalling male condition, such as testosterone-mediated displays and body size. Numerous investigators have proposed that traits linked to testosterone honestly reflect male condition. We conclude that ornate plumage may not play a primary role in female choice, because it may not accurately indicate male quality. (C) 2001 The Association for the Study Animal Behaviour.