The Canvasback (Aythya valisineria) is a species of duck.
This species from North America, is a rare vagrant to Britain, recorded very few times. Similar to the Pochard, this species has a longer, completly black bill, and a very pale body. Males have a red
Male Canvasback - http://www.flickr.com/photos/qwertyqwertyqwerty/
head and black tail and breast, whereas females have a brown breast, head and tail, and is generally duller.