In fact the only difference is the color of their bills. The males bill is solid yellow. The female has a yellow bill which is spotted or painted with olive gray. Body plumage is dark brown and feathers are thinly edged with beige. The crown is dark and sides of the head and neck are beige or light brown.
Legs are orange-red.
Looks almost identical to the black duck found in the Atlantic flyway. The top of the wings are dark brown with a dark purple speculum. The under wing is white with grayish colored tips. On fresh and saltwater mashes in both open and wooded country. The central Gulf Coast region.