Manmade nesting structures have proven to be effective substitutes for waterfowl, especially in areas where loss of natural habitat has created competition for safe nests. The species that are most likely to accept manmade nesting structures are Canada geese, mallards and wood ducks.

Both state and federal agencies have conducted numerous studies to evaluate the various concepts for increasing nesting success using large round hay bales, culverts, tree, post and floating structures. All approaches have been met with varying degrees of success; so if you're considering such a project, consult with your local game officials to see what has been most effective in your region.

Regardless of the approach, it sometimes takes several years before waterfowl are willing to try them out, but once they do, their offspring will likely return to next year after year. The number one factor in the long-term success of any artificial nesting project is maintenance after the initial installation. If structures are not maintained they will deteriorate beyond use and also become an eyesore that deters landowners from approving future projects. Waterfowl will not bring nesting materials to the nest. Prior to March 1, of each year, nests should be cleaned out and new material added.

Geese
A simple, but effective project for geese can be made from a plastic drum cut in half, with a 6-inch escape hole in the side to facilitate goslings dropping down into the water. This hole should extend to about two inches from the bottom of the tub. A goose tub should be large, up to 32 inches wide and about a foot deep. Once crafted, the tubs should be erected on poles in two to three feet of water, with the bottom of the tub three to four feet above the normal high water level, and about 50 feet from shore if possible. As a general rule of thumb, install one tub per acre of wetland and make sure that you have at least 150 feet between tubs.

Mallards
Mallards readily adapt to cylinders that are made of welded wire and filled with straw, hay or other suitable nesting material. The system is built by using two cylinders, one inside the other, with nesting materials between the two. The inner cylinder should be two to three feet long with a 12-inch diameter, placed inside a cylinder with a 14-inch diameter. Placement should be similar to the goose nest guidelines above, except that mallards like their nests positioned along the edges of and just above the tops of cattails or bulrushes.

Wood Ducks
Wood ducks have an impressive comeback history due to the diligent waterfowlers who built and distributed tens of thousands of nesting boxes to replace diminished habitat. Other secondary cavity nesters such as Barrow's goldeneye, and bufflehead also benefit from manmade nesting boxes. Wood duck nests should include a hardware cloth ladder for duckling exit, a predator guard, and drain holes in the bottom to keep nest materials dry. Boxes can be built of cedar, which is resistant to rot without treatment, or other woods such as pine, spruce or plywood. Treatment of the exterior is possible, using a natural color preservative, however, the interior should never be treated.

For protection from predators, place the nest on a pole or tree six to 10 feet above dry land or four to five feet above normal water level. Use one nest for every two acres of wetland to begin with, but increase to two per acre after nesting females are established.

Old nests and those of invasive species such as European starlings must be cleaned out regularly if the boxes are to be used more than once during a nesting season. The monitoring program should ensure that boxes are monitored at least once before the beginning of the nesting season, and should be checked at least once a month during the nesting season, if multiple use of nest boxes per nesting season is desired. Boxes should remain out during the winter to provide winter cover sites for screech owls and other resident birds.