Wood Duck
(Aix sponsa)

Cover - Nesting

Wood ducks nest in natural tree cavities and in some cases, those excavated and abandoned by woodpeckers. Nesting boxes are also readily accepted for nesting. Nesting pairs typically select cavities in deciduous woodland areas in close proximity to rivers, wetlands, and other suitable aquatic habitats used for brood rearing. Cavities located 30 feet or more above the ground are preferred, but the height can vary from near ground level to 65 feet. Suitable natural cavity dimensions typically have an entrance hole diameter of at least 4 inches, an inside diameter of approximately 6 to 8 inches, and a depth of at least 24 inches. Optimal nesting habitat contains up to five suitable cavities per acre in close proximity to brood-rearing habitat; however, since most natural cavities are not suitable for use by nesting wood ducks, these conditions frequently require that 50 or 60 natural cavities per acre exist. This illustrates the utility of providing suitable artificial nesting boxes to augment the availability of natural cavities.

Cover - Brood Rearing

Wood duck broods require shallow water for foraging on invertebrates and aquatic plants that contain some protective cover from predators. A ratio of 50 to 75 percent cover to 25 to 50 percent open water is preferred as brood-rearing (and breeding) habitat. Cover may be provided by trees or shrubs overhanging the water, flooded woody vegetation and debris, and herbaceous emergent vegetation. Ideal shrub cover is provided by mature shrubs that provide a dense canopy about two feet above the water surface. Button bush is an important shrub species in a large portion of the wood duck's range due to its brushy growth form, providing brood cover, and its prolific seed production, used heavily by foraging adults. Reliance on permanent, deeper water bodies for brood habitat should be avoided to minimize duckling mortality from aquatic predators such as snapping turtles and large fish.

Adult molting cover requirements are generally met by suitable brood-rearing habitat. Permanent water, cover, and food are the key elements of molting habitat.

Cover - Winter

In areas where wood ducks winter, areas similar to brood rearing habitat provide adequate winter cover. Bottomland hardwood wetlands and quiet river backwaters and streams with an abundance of partially submerged downed timber, shrubs, and woody debris are favored. Winter-persistent herbaceous emergent vegetation that has a shrubby-like life form (e.g., cattail, soft rush, bulrush, bur-reed, etc.) may also provide adequate winter cover. Security provided by overhead woody cover is the key element of good wood duck roosting habitat.