American Black Ducks breed mostly in freshwater wetlands throughout northeastern North America, including beaver ponds, brooks lined by speckled alder, shallow lakes with reeds and sedges, bogs in boreal forests, and wooded swamps. They may also nest in saltmarshes. They mostly spend the winter in saltwater wetlands, but also in beaver ponds, flooded timber, agricultural fields, and riverine habitats. They often take refuge from hunting and other disturbances by moving to fresh and brackish impoundments on conservation land. Back to top
American Black Ducks eat mostly plant matter, with insects added during the breeding season. Plant foods include seeds, roots, tubers, stems and leaves of plants growing in moist soil and underwater. In the breeding season adults and ducklings eat a diet high in animal foods, including aquatic insects (larvae of mayflies, caddisflies, dragonflies, flies and midges, and beetles), crustaceans, mollusks, and sometimes fish. They forage individually or with their mates in the nesting season, and either alone or in small groups during the rest of the year. In shallow water they forage like typical “dabbling ducks” by submerging their heads, or tipping up to reach underwater food. In deeper water they may dive more than 12 feet deep for plant tubers and other food items. On migration they eat seeds, foliage, and tubers of aquatic plants, agricultural grains, seeds and fruits of wild terrestrial plants, invertebrates, and sometimes fish and amphibians. Wintering birds eat mostly plant parts in freshwater habitats, adding foods such as mussels, zooplankton, and small fish in marine habitats.Back to top
The female selects a well-concealed site, often on the ground, on wooded or grassy islands, uplands, marshes, cultivated croplands, or cropland borders. She may choose a site in a shrubby area, a brush pile, a hay bale, a patch of grass, or a rock crevice. Nests are sometimes in crotches, hollows, or cavities of large trees.
The female builds the nest on her own, digging with her feet and bill in leaf litter or soil to form a basin 7–8 inches across and 1.5 inches deep. While laying eggs, she adds plant material gathered within reach of the nest, including grass, twigs, leaves, stems, and conifer needles. By the fourth or fifth egg she starts adding down feathers plucked from her own body, until the clutch is fully covered at the beginning of incubation.
|Clutch Size:||6-14 eggs|
|Number of Broods:||1 brood|
|Egg Length:||2.2-2.5 in (5.5-6.4 cm)|
|Egg Width:||1.6-1.8 in (4.1-4.5 cm)|
|Incubation Period:||23-33 days|
|Egg Description:||White, cream-colored, or pale greenish buff.|
|Condition at Hatching:||Well developed and covered with down.|
American Black Ducks are slow, heavy fliers but excellent swimmers, diving to avoid predators and sometimes to find food. Mates are monogamous within each breeding season, and the pairs may stay together in subsequent years. They court and form strong pair bonds in the fall and winter before migrating to breeding grounds. Nesting starts in February in the southern part of their range, but often not until late May in the northern part. The female incubates the eggs while the male defends the territory. Pairs nest near each other fairly peacefully unless one male or pair intrudes; then the territorial male threatens, chases, and fights the intruders. Halfway through incubation, the male becomes less attentive and eventually abandons the nest. The ducklings hatch all within a few hours, and once they are dry the female leads the brood to rearing areas with a lot of invertebrates and plant cover. In early September, after molting, the adult and fledgling ducks join up near breeding areas and begin to migrate south.Back to top
American Black Ducks are common, but the North American Breeding Bird Survey recorded a decline of about 84% between 1966 and 2014. Since 2004, declines have slowed down. They are not on the 2014 State of the Birds Watch List. Farming, logging, and urbanization in this species’ breeding and wintering habitats, both inland and on the coast, may have contributed to the fall in numbers. Duck hunters intensively exploited American Black Ducks for decades, shooting an estimated 800,000 per year in the 1960s and 1970s. In 1982 the Humane Society of the U.S. pursued a lawsuit that led to stringent hunting restrictions the following year, namely a 30-day season with a one-bird limit per day. Annual harvest in the 1990s was estimated at 166,000 in the U.S., and today records indicate that figure is about 115,000 per year. American Black Ducks are warier than many other duck species, such as Mallards, and thus less tolerant of disturbance. Mallards may have even contributed to the decline in black ducks, since Mallards thrive under urban conditions and may oust their shyer cousins from the habitat (as well as altering local populations by hybridizing with them). Like other aquatic animals, American Black Ducks are sensitive to pollution and runoff that degrade water quality. In the mid-twentieth century the pesticide DDT contributed to eggshell thinning. American Black Ducks also are vulnerable to lead poisoning when they eat spent lead shot while foraging in wetlands.Back to top
Longcore, Jerry R., Daniel G. McAuley, Gary R. Hepp and Judith M. Rhymer. (2000). American Black Duck (Anas rubripes), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.
North American Bird Conservation Initiative. (2014). The State of the Birds 2014 Report. US Department of Interior, Washington, DC, USA.
Raftovich, R. V., K. A. Wilkins, S. S. Williams and H. L. Spriggs. (2012a). Migratory bird hunting activity and harvest during the 2010 and 2011 hunting seasons. Laurel: US Fish and Wildlife Service.
Sauer, J. R., J. E. Hines, J. E. Fallon, K. L. Pardieck, Jr. Ziolkowski, D. J. and W. A. Link. The North American Breeding Bird Survey, results and analysis 1966-2013 (Version 1.30.15). USGS Patuxtent Wildlife Research Center (2014b). Available from http://www.mbr-pwrc.usgs.gov/bbs/.
Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, USA.