nest boxes

A small group of us, all volunteers, maintain and monitor the Wood Duck nest boxes at Huntley Meadows Park, in southern Fairfax County, Virginia.

Each spring there are six or eight of us -- four regulars plus some new recruits who work a season or two. Our job is simple: to keep the boxes clean and secure for the ducks, and to count the eggs that are laid and hatched.

We maintain about 20 boxes in the park. Most of them are spread along the main wetland, and you can see several of these boxes from the boardwalk and the Heron Trail. A few are in a smaller wetland on the north side of the park. The number of boxes varies a bit from year to year, as we add new boxes and old ones succumb to the elements.

The boxes are mounted about three to six feet above the ground or the water surface, so that they are easily accessible to us. However, some people wouldn't consider slushing through six inches of mud and three feet of water easy access!

The boxes are made of wood, most of them with a hinged door on the side, but in the 1990's we also had success with boxes made from two 5-gallon plastic buckets, one inverted over the other, and fastened with screws. While the plastic boxes were somewhat more durable, we sometimes had a problem with rainwater getting inside them.

The plastic boxes also seemed to be resistant to predators, so we don't mount troublesome shields under them. Boxes mounted on poles rather than trees also appear to be more predator-resistant. Among the intruders that have turned up in the boxes are squirrels, snakes, nesting wrens and starlings (and once a Great Crested Flycatcher [Myiarchus critinus]), and countless wasps.

As of 2001, Hooded Merganser (Lophodytes cucullatus) has begun nesting in the park! We found two clutches in '01 and three in '02.

We start work in the field in late February, repairing broken boxes and relocating those that the birds don't seem to use. On our first full walkthrough of the park, we lay down a fresh bed of cedar chips in each box. We go on to check each box every Sunday morning.

By mid-March, we see signs that the ducks are visiting the boxes. At first, the only evidence is a shallow depression in the chips or a shed feather. Toward the end of the month, the hens start laying.

The clutches are usually complete in April, and the 28-day incubation period begins. Although we continue to check each box, we are respectful of the birds. If an incubating hen doesn't flush (doesn't leave the box), we back off.

We often see cases of brood parasitism -- sometimes as many as 30 eggs in one box! At about 6 o'clock in this photo, notice the discolored egg, which has already failed. But from these so-called dump nests, perhaps 18 or 20 eggs will hatch. And once the chicks hatch, they're very much on their own, anyway.

The monitoring volunteer is holding aside the nest's layer of insulating down, which the hen supplies by plucking it from her breast.

Hatching occurs in late April, throughout May, and sometimes into June. We never see the blessed event itself, only the residual shells, membranes, and down. By Memorial Day, the breeding season is winding down. And just in time: walking about in the Washington heat in hip waders is not my idea of fun.

Here is the result of all this work by the ducks, with a little help from us. This little guy was left behind in a box last season, and unfortunately its prospects aren't good. But ten to fifteen of his clutchmates departed the nest successfully, to go on to make more Wood Ducks.

I gave a presentation about the nest box monitoring program at the park to a birding class led by P. J. Dunn in March 2015.