Most of our domestic breeds of duck are descended from the Mallard Anas platyrhynchos. This breed takes its name from Cayuga Lake (which is itself named after the native Cayuga People). Some assumptions are made that it is partly descended from the American Black Duck, which is the closest wild relative of the Mallard. The Cayuga drake develops a tail curl like a Mallard, which the American Black Duck does not.
The drakes tend to retain their black plumage better than the females which can develop white patches as they get older. It seems that unfortunately the birds with the brightest sheen tend to turn white earlier. This can be selected against, and some birds do remain black into later life.
The Cayuga is a heavy breed with drakes weighing: 3.6kg (8lb) and the ducks weighing: 3.2kg (7lb). When the ducks are in full lay you can expect between 50-100 eggs per year. The earlier eggs have a washable dark pigment on the shells which becomes less intense as the season progresses.