The Chiloe wigeon (Anas sibilatrix), also known as the southern wigeon, is indigenous to the southern part of South America, including the Chiloe Archipelago - a group of islands lying off the coast of Chile. When communicating, both sexes lift their chin and call in the same way: a whistle. Males have white wing patches, white cheeks and forehead and a metallic green head. The breast is barred white and black and sides are orange-brown. The back is dark grey with white streaks. These ducks have grey bills with black tips. The legs and feet are dark grey. Chiloe wigeons have strong pair bonds and - unlike other widgeons - males often take part in rearing the young; however, the female alone incubates the eggs. Chiloe wigeons join the very small number of waterfowl species that have managed to cross the hostile South Atlantic (Drake Passage) separating the tip of South America from Antarctica.