D'Vera Cohn has been writing a lot of bird-related articles in the Washington Post lately. The latest is an article on the nest boxes maintained at Huntley Meadows in Fairfax County. Huntley Meadows used to belong to the military. Sometime around mid-century, beavers flooded most of it, and the land was turned over to the county for use as a wildlife park. Huntley has a mix of marsh, meadow, and bottomland woods. It became a good place to spot birds unusual this close to the District. Huntley's combination of habitats provides for a variety of breeding birds, including ducks that use artificial nest-boxes.
To see what a wood duck nest box looks like, see here.
Until recently, the nest box team watched out only for wood ducks, which traditionally have nested in tree cavities but have been helped along by man-made boxes. During the spring breeding season, the males are among the most elaborately painted ducks around, with hues from green to burgundy. Five years ago, the volunteers noticed a new duck species in their nest boxes: hooded mergansers. In spring, the male duck is distinguished by a large white spot on the back of its dark head. In the duck world, the males are the ones with the showy plumage.
Paul Baicich, a longtime birder who also is on the nest box-monitoring team, said Huntley Meadows may have more nesting hooded mergansers than any other place in Virginia. The nest box volunteers have records going back to 1982 that show the natural ups and downs in duckling trends. In some years, they counted more than 100 ducklings, in others fewer than 50.
Different birds have different breeding and child-rearing arrangements. In the case of these species, the ducklings can leave the nest almost right away.
A female does not begin to incubate her eggs until she has laid a dozen or so, one each day. Then she builds a nest around the eggs with her down. She sits on them for most of the day, leaving only for a daily food run. The males provide no help.