In studies partly supported by Ducks Unlimited that I conducted at Mississippi State University from 1994 to 2001, I determined that nest box maintenance during the breeding season significantly increased wood duck production. Oftentimes, managers of wood duck nest houses only visit and inspect structures in late summer after the birds have completed nesting. Wood ducks do not bring material (e.g., sticks) to a site to construct nests. In natural cavities, they deposit their clutch of eggs in their own down feathers, dead wood, and other material in the cavity. In nest boxes, we should provide three to four inches of material, such as wood shavings, to provide excellent nesting conditions. Early in the nesting season, wood ducks may frequently abandon nests for various reasons or lose their eggs to predators. Thus, the removal of dead eggs and refurbishing nest boxes with clean shavings can increase wood duck production significantly. For example, at our study sites in Mississippi and Alabama, we found that 38 to 65 percent of total wood duck ducklings produced occurred in second or third nesting attempts. It is likely that duckling production may have been greater had abandoned and destroyed eggs been removed from the boxes. Thus, our and other studies show that nest box maintenance during the breeding season (i.e., monthly inspections) could tremendously boost duckling production. However, remember that federal law prohibits removing eggs of migratory birds from nests. Thus, one must be certain that wood duck nests are no longer viable before initiating nest maintenance activities.
In the same study, we addressed survival of wood duck ducklings exiting man-made nest houses. To do so, we equipped 135 female nesting wood ducks and more than 400 ducklings with radio transmitters. We monitored survival and other aspects of duckling ecology from March through July at two study areas from 1996 to 1999. We determined that duckling survival was low overall at about 20 percent. However, we discovered that, when ducklings traveled more than a mile per day to densely vegetated shrub habitats that did not contain nest boxes, their survival was as great as 60 percent. Nest houses typically have been installed in high densities and in visible locations over water in North America. As attractive as this may be to nesting wood ducks, it also may be beneficial to predators of ducklings. Thus, we recommend that nest boxes be scattered amidst scrub-shrub habitat, and not scattered in open environments, which may attract predators.
DU Habitat Efforts
Habitat is one critical factor that influences waterfowl populations in North America. Ducks Unlimited prides itself on partnering with various governmental and other agencies to protect and restore habitats critical for waterfowl, wetlands, and other environments. Because of the extensive breeding and wintering range of the wood duck, DU’s habitat projects in nearly every state could benefit wood ducks at some time during the birds’ annual biological activities.
In the Mississippi Alluvial Valley (MAV), the region extending from southeast Missouri to southern Louisiana, more than 24 million acres of bottomland hardwood forest were once present; only 4.5 million acres remain today. Thus, DU continues to partner with several agencies to deliver habitat restoration projects. The Wetland Reserve Program, administered by the U.S. Department of Agriculture’s Natural Resources Conservation Service, has been invaluable to wood duck and other waterfowl habitat restoration efforts. To date, DU has helped plant 33.9 million seedlings of bottomland hardwood forest tree species on 160,000 acres in the MAV.
In addition, 31,000 acres of wetland hydrology have also been restored there. In Mississippi, Arkansas, and Louisiana alone, 16 million tree seedlings have been planted since the 1990s. Restoration of bottomland hardwood forest and associated wetlands will provide abundant food, natural nesting cavities, space, and critical environmental benefits. Such habitat restoration efforts are measures to help ensure the welfare of wood ducks and myriad other species of North American wildlife.