ID problem with head pattern on ducks
Black duck / Anas superciliosa.
Except for the metallic- Green speculum on the wing, this head pattern is characteristic, but not quite diagnostic, as many hybrids between Black duck and the introduced Mallard also show this feature.
Mallard / Anas platyrhynchos
The male Mallard in breeding plumage can hardly be mistaken for any other duck, but in eclipse both it and the female are very similar to the Black duck. In the hand both can be distinguished by the speculum on the wing which has a distinctly Purplish tinge, but this is not easy to see at a distance; much more conspicuous - and diagnostic - is the white anterior border to the speculum.
Maybe others have photos to post to help us all.
