By Keith Gauldin, Wildlife Biologist, Division of Wildlife and Freshwater Fisheries

The wood duck (Aix sponsa) would most likely serve as the representative waterfowl species in Alabama due to its year-round abundance and popularity. Well recognized by its vivid colorful plumage, it is also sought after by many waterfowl enthusiasts. Currently, wood ducks are abundant in Alabama and represent the second most harvested waterfowl species in the state. They provide challenging wing shooting as they dart through wooded swamps and beaver ponds, and are excellent for the frying pan as well.

Unfortunately, there was a time at the turn of the century that wood ducks were not doing so well. The lack of protection and management left them in a precarious position. But today, through proper protection in the form of hunting regulations and proper habitat management, wood duck populations have rebounded substantially to several million in North America.
Though the wood duck is currently faring well, factors remain that limit populations in many areas. The most significant of these factors is the availability of suitable nesting cavities. Unlike most other species of waterfowl, wood ducks utilize cavities for nesting, either natural or artificial. Historically, they would use natural cavities of hollowed trees but the clearing of lands for agriculture and development and the harvest for paper pulp and lumber has decreased the abundance of these crucial nesting areas. In order to supplement these nesting sites, nest boxes can be constructed and placed in key sites.
Wildlife biologists from various federal and state agencies have developed a variety of designs for the wood duck with varying results. The nest box constructed of wood is by far the most popular due to its simple construction and ready acceptance by wood ducks. Cypress or cedar is the lumber of choice, which is characterized by being rot and insect resistant, increasing its longevity.
The key elements to the nest box design should include:
  1. An oval shaped entrance hole 3 inches high and 4 inches wide, which is important to target the use of the nest box to wood ducks.
  2. A 4-inch-wide strip of hardware cloth fastened to the inside of the box from the bottom of the entrance hole extending to the floor. This will function as a ladder for the hatchlings to exit the box. Be sure to bend the sharp cut edges of the cloth inward towards the box surface to avoid injury to the young ducklings.
  3. A layer of approximately 3 inches of wood shavings or coarse sawdust in the box to serve as suitable nesting material, as wood ducks do not bring nest material to the cavity.

One of the most important elements of the next box is the predator guard. Typically fashioned from sheet metal and permanently affixed to the box mounting pole, the guard acts as an umbrella that prevents predators from climbing the mounting pole and is crucial in the aspect of successful nesting. Nest boxes without predator guards can make wood ducks easy prey and cause negative population effects.

Site selection plays a key role in the use of artificial nest boxes. Wood duck hens prefer areas to themselves away from other hens and/or disturbances to the nest. Box sites should be visibly isolated from one another to provide hens a degree of secrecy and to deter other hens from utilizing the same nest. An ideal pole-mounted box location would be within 200 feet of a wetland or waterway edge. Limbs of over-hanging trees adjacent to the box should be trimmed accordingly to minimize possible avenues of predation. Make sure there are no natural or man-made barriers that would prevent the ducklings from accessing the water following their exit from the box.

While the nest boxes can be mounted on either artificial poles or directly to trees, using erected poles minimizes access from tree-climbing predators. The boxes should be securely mounted on poles of either pressure-treated wood or metal, preferably at least 5 feet above the high water level in areas subject to fluctuating water levels. Fasten predator guards to the poles at least 4 feet off the ground or water’s surface to decrease chances of predators accessing the box.

Annual maintenance and monitoring should be an established practice on all wood duck nest boxes. For Alabama, wood ducks can begin nesting as early as February, so conduct these practices during the winter months to avoid the possibility of disturbing nesting hens. At this time, remove old nesting material and replace with fresh. Sometimes there are other interesting things you can learn at this time such as how many egg fragments are left from the previous year’s hatch or if any un-hatched eggs are present, or you may be able to see where other wildlife has used the box.

Participation in this type of wildlife management is a great way of introducing youngsters to nature as well as providing an opportunity for a fun family day in Alabama’s outdoors.