Description of a xanthochroic House Finch (Haemorhous mexicanus) from Jalisco, Mexico

Plumage coloration is important to birds for communication, camouflage, physiological processes, and mate selection. In rare individuals the coloration is disrupted, which provides opportunities to scrutinize the processes that normally produce it. Male House Finches (Haemorhous mexicanus) normally sport a red head and chest, a brown back, and whitish underparts with light brown streaks. We captured a House Finch with disruptions in both melanin and carotenoid pigmentation in an urban park in Guadalajara, a city in west-central Mexico. The bird was largely orange with little eumelanin pigmentation. This is the first record of which we are aware of a hypomelanistic House Finch with carotenoids that are abnormally distributed and with an overexpression of carotenoid pigments or pheomelanins or both.