By Charles R. Sharp, Former Wildlife Biologist, Division of Wildlife and Freshwater Fisheries
Most waterfowl migrate in the spring to breeding grounds in the northern U.S. and Canada; however, not all waterfowl migrate. The wood duck is one example. Even though some wood ducks do migrate north to breed, there are many that remain in the south during breeding season if conditions and habitats are favorable. Historically, the limiting factor for wood duck breeding in Alabama has been the availability of nesting sites. Wood ducks are cavity-nesting birds. With the change of forestry practices to shorter rotations of timber harvest, most trees do not reach sufficient size to develop cavities to accommodate wood ducks nests. In the 1960s, the lack of cavities restricted the breeding efforts in the South. To help reestablish the breeding population, a wood duck nest box program was initiated. Wooden nest boxes were installed on trees or on poles over or near water. The initiation of the wood duck box program turned around the decline of wood ducks breeding in the state.
Improving wood duck nesting was an important step in improving wood duck habitat, but it is only the first step. It does us little good to increase the number of wood ducks breeding in the South if we do not provide adequate brood rearing and feeding areas for these birds to raise their chicks. The need for a plentiful source of food begins even prior to nesting. Researchers estimate that a wood duck hen will consume a few thousand aquatic insects just to produce one egg and a wood duck may produce a clutch of 12 eggs. You can imagine the volume of aquatic insects required to produce just one clutch of eggs. After hatching, wood duck chicks require an abundant high protein food source with adequate protection from predators in close proximity to their food source.
The aquatic habitats that wood ducks almost exclusively utilize are emergent scrub/shrub and forested wetlands. Wetlands commonly occur along the floodplains of rivers, streams, and lakes as natural occurrences or with the aid of beaver colonies or man. When flooded, these lowlands, with their thick layer of leaf litter, provide ideal conditions for the growth of aquatic invertebrates and insect larvae. These seasonal wetlands are the type of habitat that is normally easiest to manipulate for wood ducks. Many times all it takes is the plugging of a ditch with an earthen plug or small control structure to impound several acres. If you have beaver activity in the area, let them do most of the work building the dam. After broods have attained the ability to fly, usually in mid to late spring, the dam should be opened to lower the water level. Lowering the water level during the late spring and summer months allows the hardwood trees to survive.
Wood ducks require a variety of wetlands types throughout the course of the year. During the spring and summer, when many of the flood plains are being rejuvenated, the adult wood ducks with their young will move to more permanent bodies of water such as streams and ponds. It is important to remember that unlike managing for migrating waterfowl that are in the south for a short period of their yearly cycle, managing for wood ducks requires their needs to be met year round. Managers that are interested in wood ducks must meet those needs.
Wood ducks are our resident waterfowl. In addition to being enjoyed by hunters, because of their natural coloration, they are one of the most often painted and photographed species. Wood ducks are truly enjoyed by people with a wide spectrum of interests. With a little effort, habitat can be improved on a significant portion of the landscape.