The first one that comes to mind is the Shellduck,
The male has a green head but the rest of it is nearly all
black and white with a bit of brown. Other male ducks with green heads are Mallard, Shoveler, Goldeneye, Gooseanderand and perhaps the Merganser.
The females of all these species have brown heads
except the Shellduck which has a lot of white on it.
Not a lot of help I'm afraid!