Although its still cold outside, now is the time to prepare for the arrival of ducks later this spring. Many people enjoy building and installing wood duck nesting boxes and mallard nesting cylinders. These artificial nesting sites are readily used by ducks and can provide a safe nesting location, but they do require simple annual maintenance. According to Steve Delehanty, manager of the U.S. Fish and Wildlife Services Morris Wetland Management District in western Minnesota, late winter is the perfect time to install and maintain nesting structures so theyre ready for use when the ducks return in April and May. Although simple, an annual spring cleaning is necessary to encourage the use of these structures by hen wood ducks and mallards.
"Wood duck boxes are a good example," explained Delehanty. "Theyre simple to maintain but, without annual maintenance, become useless to ducks." Each year, between the end of one nesting season and the beginning of another, Delehanty recommends nest boxes be opened and cleared of any nesting debris. After cleaning, add several inches of clean wood chips or wood shavings to the bottom of the box. Unlike other birds, wood ducks do not gather nesting materials to create a nest so wood chips or shavings are needed. Hens may also add their own feathers for added cushion and insulation.
According to Delehanty, if you carefully remove the old nest debris, you can tell if the box was used by a duck and whether or not the nest was successful. When ducklings emerge from the egg, they leave behind the thin, leathery membrane which originally surrounded the embryo. Even though the hatched egg shells are usually broken into tiny pieces, the dried egg membranes usually remain in the nest bowl. There is one membrane for each hatched duckling, each about the size and shape of a half-dollar coin. If you find broken egg shells with no membranes, the eggs may have been eaten by a nest predator. If this is the case, consider moving the box or installing a predator barrier on the mounting pole or tree.
Occasionally, you will find a nest full of unhatched eggs. "Wood ducks frequently lay eggs in various nesting cavities before settling down to create their own nests," Delehanty said. "These sites for early egg laying are called dump nests and sometimes many hens will lay eggs in the same dump nest; you could find thirty or more unhatched eggs that were never incubated." Even more rarely, a duck will attempt to incubate the eggs in a dump nest and, while many eggs fail to hatch, she may bring off an extra large brood of twenty or so ducklings.
Wire and straw mallard nesting cylinders, sometimes called hen houses, also require brief annual maintenance. Each year, clean out old nests and stuff a generous handful of hay or straw into the gap between the wires that form the cylinder. "Stuff some straw inside the cylinder too so its filled roughly halfway to the top," Delehanty advises, "but leave enough of an air gap inside the cylinder so the hen can see through from one end to the other."
If you have several nesting cylinders to maintain, its handy to fill a feed sack or pack with slough hay. That hay, along with pliers and perhaps a scrap of wire for emergency repairs, are all you need to maintain a number of nesting cylinders. In the north, late winter is also a good time to install new nesting cylinders by drilling holes through the ice and pounding mounting posts into the marsh bottom.
For more information on the proper design and placement of nesting structures, visit your nearest Wetland Management District or National Wildlife Refuge. To find the nearest office visit our website at http://midwest.fws.gov">
The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 93-million-acre National Wildlife Refuge System which encompasses more than 530 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 66 national fish hatcheries, 64 fishery resource offices and 78 ecological services field stations. The agency enforces Federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state fish and wildlife agencies.
