About Tachyeres leucocephalus Humphrey & Thompson, 1981
Adult male Chubut steamer ducks (Tachyeres leucocephalus Humphrey & Thompson, 1981) have white heads and a bright yellow-orange bill with a black nail. Their feet and webbing are yellow-orange with black claws. Most of their remaining body plumage is grey, and their bellies are white. When an adult male is molting, its bill fades to a duller yellow-orange. Adult female Chubut steamer ducks have brown heads and necks, with a thin white line running from the back of the eye to the fore-neck. Their bills are greenish-yellow. Adult females closely resemble juvenile Chubut steamer ducks. The Chubut steamer duck was originally thought to occur only along the southern coast of Chubut province, Argentina. It is now known to have a larger range extending from the southern part of San Matías Gulf to Islote Chato. Key populations of the species are located in Bahía San Gregorio (Argentina), Bahía Melo, and Caleta Malaspina, all of which sit within the San Jorge Gulf.
