Rare and very local on Rio Grande river. Feral populations established in s. TX and FL, though often found elsewhere with other 'farmyard' ducks. Wild birds very wary and usually only seen flying 'down river.' Crepuscular. ID: Very large and heavy with bulging sternum and sloping forehead. Wild birds are blackish with variable irredescent purple or green. Female duller. Striking white patches on underwing and forewing (lacking in very young birds). Feral birds variable but almost always with white in body plumage and more extensive red bare skin in face.