By Tawna Mertz American black ducks nest throughout the Chesapeake Bay watershed, from the rivers and streams of Pennsylvania to the tidal freshwater wetlands of Virginia. Thousands of black ducks also migrate from breeding grounds in the extreme northeastern United States and southeastern Canada to overwinter in Bay tributaries and wetlands. Although most of the Bay's migratory waterfowl are increasing, the number of both migratory and resident black ducks continues to decline. Once the premier dabbling duck pursued by hunters, their numbers have dropped from more than 100,000 in the mid-1950s to around 30,000 in the late 1990s. But many experts also blame competition for prime breeding habitat from the rising resident mallard population and overhunting.
Black ducks use wetlands for nesting and raising young.
In fact, black ducks need two types of habitat to successfully raise young, They need a secure nesting area, with cover from overhead predators, like gulls, and isolation from land-based mammal predators, like foxes, rats and raccoons. These two habitat types must be close enough together for young ducks to survive the swim. In the past, islands provided excellent habitat for breeding black ducks. Their isolation from land-based predators and habitat gradients from uplands with trees and shrubs to surrounding marshes with emergent and submerged plants were perfect. But islands have been rapidly disappearing from Chesapeake Bay, the result of erosion and sea level rise.