A female mallard sips from warm springs Aug. 27, 2011, outside Beuna Vista, Colo. Plants and insects represent most of the mallard’s diet. They prefer to dabbling in water that is less than 16 inches deep, where they can duck down and reach plants at the bottom. Mallards sift through the mud with teethlike fringes to trap food and drain water. They sometimes eat crustaceans and mollusks. In North America, mallards breed from Alaska to South California, Colorado, Kansas, Ohio and Virginia. Mallard ducks are the ancestors for almost all other domestic ducks. Domestic ducks belong to the subfamily Anatidae.