During the breeding season, it is usually found in coastal and freshwater wetlands from Saskatchewan to the Atlantic in Canada and the Great Lakes and the Adirondacks in the United States.

The female lays six to fourteen oval eggs, which have smooth shells and come in varied shades of white and buff green.

The United States Fish and Wildlife Service has been purchasing and managing the habitat of this species in many areas to support the migratory stopover, wintering and breeding populations.

The Atlantic Coast Joint Venture also protects habitat through restoration and land acquisition projects, mostly within their wintering and breeding areas.

"[2] In a typical obscura, characteristics such as greenish black, olive green or dusky olive bill; olivaceous brown legs with at most one reddish tinge; the nape and pileum nearly uniformly dark; spotless chin and throat; fine linear and dusky markings on the neck and sides of the head, rather than blackish, do not vary with age or season.

[7] In the United States, it is found in northern Illinois, Michigan, New Jersey, Ohio, Connecticut, Vermont, South Dakota, central West Virginia, Maine and on the Atlantic coast to North Carolina.

[16] It usually prefers freshwater and coastal wetlands throughout northeastern America, including brackish marshes, estuaries and edges of backwater ponds and rivers lined by speckled alder.

[15] Ducks usually take shelter from hunting and other disturbances by moving to brackish and fresh impoundments on conservation land.

[8] Ducklings mostly eat water invertebrates for the first 12 days after hatching, including aquatic snowbugs, snails, mayflies, dragonflies, beetles, flies, caddisflies and larvae.

[19] It is partially migratory, and many winter in the east-central United States, especially coastal areas; some remain year-round in the Great Lakes region.

[20] This duck is a rare vagrant to Great Britain and Ireland, where over the years several birds have settled in and bred with the local mallard.

[22] Both sexes share duties, although the male usually defends the territory until the female reaches the middle of her incubation period.

[24] It has been proposed that the American black duck and the mallard were formerly separated by habitat preference, with the American black duck's dark plumage giving it a selective advantage in shaded forest pools in eastern North America, and the mallard's lighter plumage giving it an advantage in the brighter, more open prairie and plains lakes.

[25] According to this view, recent deforestation in the east and tree planting on the plains has broken down this habitat separation, leading to the high levels of hybridization now observed.

[23] The American black duck and the local mallard are now very hard to distinguish by means of microsatellite comparisons, even if many specimens are sampled.

Their statement, "Northern black ducks are now no more distinct from mallards than their southern conspecifics" only holds true in regard to the molecular markers tested.

[32] However, the reduced viability of female hybrids causes some broods to fail in the long run due to the death of the offspring before reproducing themselves.

Recent research conducted for the Delta Waterfowl Foundation suggests that hybrids are a result of forced copulations and not a normal pairing choice by black hens.

[34] The United States Fish and Wildlife Service has continued to purchase and manage habitat in many areas to support the migratory stopover, wintering and breeding populations of the American black duck.

[14] In addition, the Montezuma National Wildlife Refuge has purchased and restored over 1,000 acres of wetlands to provide stopover habitat for over 10,000 American black ducks during fall migration.