Webbed beauty: Wood ducks are a success story
My 4-year-old grandson, Lincoln, and I planted an apple tree in the backyard recently. I chose a sunny area on the backside of the house near a couple of large bur oak trees and other assorted trees and shrubs. About 10 feet high on one of the stately oaks is a wood duck house that has remained in remarkably good condition despite it being 16 years old already.
The artificial nest box is of the classic design and dimensions and made out of white pine lumber that's outfitted with a side door for easy access and maintenance. Over the years the nest box has housed wood ducks, hooded mergansers, gray squirrels, kestrels, and even a few flying squirrels.
It's also used each spring as a sounding board by territorial male yellow-bellied sapsuckers. I'm positive the sapsuckers enjoy tapping out their telltale raps on the nest box for its resonant, drum-like quality.
As we were finishing planting the tree, I suddenly heard the unmistakable sound of a bird's wings. For those of you familiar with waterfowl hunting, you'll know what I mean — setting wings, rushing air ... a sound unlike that of a jet as a large bird, flying fast, descends from a higher altitude and about to land.
Knowing full well what was going on before I turned my head, I saw for only a split second the sight of a wood duck hen rocket herself into the cavity of the nest box at astonishing speed, her body and feet clamoring into the structure and into the box. For a moment I could plainly hear her settling into her nest inside the box and then all was quiet. Lincoln, too, heard the bird but did not see her, and so for the next minute or two I explained the whole thing to him.
Aix sponsa, the wood duck's Latin scientific name, is a fascinating and striking duck to be sure, particularly the drake. And while wood ducks can do most things that all other ducks do, as the species' name suggests, they have also adapted to an arboreal lifestyle. Put another way, the wood duck is as at home in the trees as they are on the water.
While the wood duck did not have it so easy around the turn of the 20th century, they are quite numerous today. In fact, some conservationists feared that because of rapid habitat depletion and unregulated hunting, the wood duck would eventually become extinct. Thankfully, in 1918, the Migratory Bird Treaty Act was passed.
This act protected the wood duck from hunting until 1941 when some 15 states began allowing one wood duck to be harvested per legal bag limit. Other states soon followed. Yet the wood duck's problems were not over with. Though making a slow comeback as a result of restrictive hunting regulations, the destruction of habitat — principally nesting habitat — proved to be the primary limiting factor to the species ultimate recovery.
Over the years through critical habitat preservation and enhancement and carefully regulated hunting seasons, along with constructing and placing artificial nesting box structures in prime breeding habitats, the wood duck is plentiful once again.
Indeed, according to a 2017 estimate by the United States Fish and Wildlife Service, there are 6.1 million wood ducks in North America. The population in Minnesota is estimated to be 100,000 birds.
As mentioned, wood ducks are cavity nesters. Other waterfowl are cavity nesters, too, including bufflehead, common goldeneye, common merganser, and the previously mentioned hooded merganser — all of which nest in naturally-occurring tree cavities and artificial nest boxes.
But it is the wood duck that has benefited the most from artificial nesting boxes.
The average clutch size for a wood duck hen is 10 to 12 eggs, but can vary from six to 19. Wood ducks will often lay eggs into other cavities and nest boxes for other wood duck hens to incubate. This practice, which is a form of brood parasitism, is often simply called "dump nesting."
After an incubation period of about a month, the ducklings hatch and leap from their tree cavity or nest box and either plop into the water or bounce on the ground below to join their calling mother.
The wonderful wood duck is arguably the most beautiful species of wild bird in Minnesota, certainly the most attractive species of waterfowl. And while other wild birds have benefited greatly from artificial nest boxes such as purple martins and bluebirds, no other duck has taken to and benefited from these human-made structures quite like wood ducks have.
And though wood duck houses are no longer necessary for their long term survival as a species, having a few nest boxes to watch and maintain is something we can do and appreciate as we get out and enjoy the great outdoors.