Twenty-six species of waterfowl are recorded from the refuge. The most commonly observed species are American black duck ("Anas rubripes"), Canada goose ("Branta canadensis"), mallard ("Anas platyrhynchos"), green-winged teal ("Anas carolinensis"), common goldeneye ("Bucephala clangula"), bufflehead ("Bucephala albeola"), and red-breasted merganser ("Mergus serrator"). Dabbling ducks use salt pannes and the upper reaches of tidal creeks, while diving ducks prefer deeper parts of the tidal creeks and the mouths of rivers and streams. Black ducks, mallards, and increasing numbers of Canada geese breed on each division of the refuge. Wood ducks ("Aix sponsa") breed on the Upper Wells and Mousam River Divisions each year.