365 Urban Species. #024: American black duck
American Black Duck Anas rubripes
This unassuming bird is easily mistaken for a female mallard. To be able to notice black ducks on a pond covered with mallards is a good goal for beginning urban nature lovers. American black ducks are darker, all over, than mallards, though not truly black. The speculum (literally: window) or colored part of a mallard's wing is blue edged with white--on a black duck it is blue-violet with no white edge. Unfortunately this detail is not always visible.
Before being overhunted in the mid-1800s (after huge increases in human population but before protective legislation) there were more American black ducks in North America than any other duck species. They are less tolerant of human changes to the environment than mallards, but are still found in some cities year-round. We see them more often in winter, when migrants take advantage of unfrozen urban waters. Some are concerned that American black ducks may be declining further, due to hybridization with mallards.