But throughout the state, thousands of ducks will instead use ready-made nests built and placed by local conservation group members, the DNR, and the U.S. Fish and Wildlife Service. Some of these nests will be wood duck houses, built of wood and installed in trees near water. Others are like the artificial nests installed along wetlands between Herman and Elbow lakes in southwest Grant County. Called hen houses , these nesting structures are metal cylinders lined with hay placed atop metal poles. Hen mallards seem to find them particularly cozy.
Hen houses give ducks safe places to nest.
Ducks normally nest in grassy areas such as road ditches, fence rows, and fields, which are also home to raccoons, skunks, foxes, and other predators that eat duck eggs. According to Dave Rave, a DNR waterfowl biologist in Bemidji, studies have shown that hen houses improve nesting success of hen mallards. In a normal duck nest, on average only two out of nine eggs hatch, due to predation. But almost all of the eggs laid in hen houses hatch. Rave says that since 1996, more than 2,000 ducklings have hatched from the 110 hen houses placed into wetlands in southwest Grant County.