Males in breeding plumage have a buffy head that is heavily streaked with black, especially through the eye and on the tip of the head. The upperparts, including the tail and wing are blackish brown. The underparts feathers are dark sooty brown, with pale reddish and buff margins. The secondaries are iridescent blueish purple, with a black subterminal border and a narrow white tip, sometimes not present. The tertials are glossy black next to the speculum, but otherwise are gray to blackish brown, and the underwing surface is silvery white. The iris is brown, the bill is greenish yellow to bright yellow, with a black nail, and the feet and legs are orange red. Females also have a greenish to olive-colored bill, with small black spotting, and dusky to olive-colored legs and feet. Juveniles resemble adults, but are more heavily streaked on the breast and underparts, since these feathers have broader buff margins but darker tips. In the field the Black Duck has a body shaped like a Mallard. In flight, Black Ducks appear to be nearly black, with an underwing coloration that is in contrast with the rest of their plumage (Johngard, 1978).
Anas rubripes breeds from Manitoba southeast to Minnesota, east through Wisconsin, Illinois, Ohio, Pennsylvania, Maryland, West Virginia, Virginia, and in the forested portions of eastern Canada to nortern Quebec and northern Labrador. The black duck winters in the southern parts of its breeding range and south to the Gulf Coast, Florida, and Bermuda (Mcauley, et al 1998).
The Black Duck during the breeding season prefers a variety of fresh and brackish waters in a forest environment. These include: alkaline marshes, acid bogs and muskegs, lakes, ponds, and stream margins, as well as tidewater habitats such as bays and estuaries. The most favored areas are brackish estuarine bays with extensive adjacent agricultural lands. Outside of the breeding season the duck lives on large, open lagoons and on the coast, even in rough sea waters (Merendino and Ankney, 1994).
The northernmost breeders descend to lower latitudes to winter on the Atlantic seaboard of North America, usually as far south as Texas. Some reports have been made of observation of Black Ducks in Korea, Puerto Rico, and Western Europe, where some have stayed for an extended period of time (Hoyo, et al 1992).
Breeding starts in March and April. Nearly all first-year females attempt to nest and older females usually return to their nesting areas of previous years and very frequently use an old nest site, or at least nest within 100 yards of an old nest site. The nest consists of a scrape on the ground, concealed among vegetation, sometimes in tree-cavities or crotches and lined with plant matter and down. Eggs are deposited in the nest at the approximate rate of one per day, and clutch sizes generally average between 9 and 10 eggs, with smaller clutches typical of first-year females. The time at which pair bonds are broken varies somewhat, with males typically remaining with their females about two weeks into the incubation period. Male participation in the brood rearing has not been reported. The incubation period is about 27 days. A fairly high rate of nest destruction is done by crows and racoons (Norman and Winston 1996). The first broods hatch in early May and peak hatch is in early June (Longcore, et al 1998). Young are mobile 1-3 hours after hatching. The female-brood pair bond lasts 6-7 weeks (Ehrlich, et al 1988).
During the fall and winter, Black Ducks are highly gregarious and may occur in flocks numbering in the thousands of birds. However, as pair formation begins about the end of September, paired birds begin to break away from the unpaired segment of the population and flock sizes gradually diminish. Pair-forming behavior occurs over a several-month period that probably peaks in midwinter, and by April nearly all the females will have formed pair bonds (Longcore, et al 1998).
The American Black Duck eats seeds and vegetative parts of aquatic plants and crop plants. They also consume a rather high proportion of invertebrates (insects, molluscs, crustaceans) in spring and summer. They feed by grazing, probing, dabbling or upending in shallow water. They occasionally dive (Hoyo, et al 1992).
The Black Duck is an important waterfowl of North American hunters and has been for many years.
Not globally threatened.
The population of the Black Duck in the 1950's was around 2 million and since then has been on a steady decrease. Today the population has been calculated to be around 50,000. Causes of decline are unknown, but probably related to habitat loss, deterioration of water and food supplies, intense hunting pressure, and competition and hybridization with Mallards (Hoyo, et al 1992).
Tracy Byerly (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.
Ehrlich, D., D. Wheye. 1988. The Birders Handbook: A field guide to the natural history of North American Birds.. Simon and Schuster.
Hoyo, J., A. Elliot, J. Sargatal. 1992. Handbook of the Birds of the World. Lynx Edicions.
Johnsgard, P. 1978. Ducks, Geese, and Swans of the World. Univ. of Nebraska Press.
Longcore, J., D. Clugston, D. Mcauley. 1998. Brood Sizes of Sympatric American Black Ducks and Mallards in Maine. J. of Wildl. Manage., 62: 134-141.
Mcauley, D., D. Clugston, J. Longcore. 1998. Outcome of Aggressive Interactions Between American Black Ducks and Mallards During the Breeding Season. J. of Wildl. Manage., 62: 142-149.
Merendino, M., C. Ankney. 1994. Habitat use by Mallards and American Black Ducks Breeding. The Condor, 96: 411-421.
Norman, S., J. Winston. 1996. Habitat-related Variations in Movements and Fledging Success of American Black Duck Broods in NE Nova Scotia. Canadian J. of Zoology, 74: 1158.