Outside: A Monthly Guide to the World Around You
Time for Precocious Ducklings to Sink or Swim
Sunday, May 7, 2006
Standing in a Northern Virginia swamp, Mike Andrien opened the hinged door of a wooden box on a pole and pulled out a light brown egg. It had been laid by a marsh-dwelling wood duck. The egg was cold, not having been sat on recently, but he was not overly worried.
That is because ducks, for all their cute appearance, are tough birds. The eggs don't need to be incubated constantly as do those of many other birds. Females often drop their eggs in a nest and leave, figuring another female will take care of them in a practice known as "dumping."
Newly hatched ducklings are protected by a down coat, and their eyes are open. They leave the nest within two days and, although they follow their parents around, find their own food. Not for them the more coddled life of a baby songbird, born naked and dependent on parental handouts for weeks. (The technical term for these ready-to-go ducklings is "precocial," related to the word "precocious.")
Andrien is on a team of volunteers that monitors duck nest boxes in Huntley Meadows Park in Fairfax County once a week from late February through the end of this month. The volunteers wear high rubber boots to wade through the wetlands and carry repair tools to keep the boxes in good condition. Once nesting starts, they often carry a small mirror that enables them to see what is inside the boxes, which are three to six feet above the ground, without having to open them.
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.
Usually the monitors do not see eggs in their nest boxes until March. But this year, they found hooded merganser eggs Feb. 26. The wood ducks started laying eggs later. 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.
The eggs of both types of ducks incubate for about a month, so May is prime hatching time at Huntley. The baby season winds down in June.
This year, the volunteers were interested to find one nest box that had eggs from hooded mergansers and wood ducks -- "hoodies" and "woodies," as Baicich put it. He is curious about how this combination will work out. But the young ducks are out the door so quickly after hatching that the volunteers do not usually see results.
"Very often we don't know what happens to them," Baicich said.
The life of a young duckling is a hazardous one, which is one reason why females lay so many eggs. One recent week, the volunteers counted 14 eggs in one nest box. They are pretty sure 11 young ducklings hatched from there. By the next week, the mother duck was escorting only six.
"Who knows -- raptors, snapping turtles, poor swimmers?" Baicich said. "I have no idea."