An adult wood duck is 18 to 20 inches long, has a 26- to 28-inch wingspan, and weighs between 1 and 1¾ pounds. The male is called a drake, the female a hen. The drake’s coloration is nothing short of exotic. His head is iridescent green, shading into blue and purple, with a slicked-back crest of feathers and a white chin-bib. His eyes are bright red, his bill reddish-orange, his legs yellow. His chest, a rich chestnut, is separated from his golden-yellow sides by vertical bars of white and black. The hen’s plumage is drab, a combination of gray, white, and brown. She has a small head crest and a circle of white surrounding each eye.
Wood ducks do not quack. The hen, more vocal and louder than her mate, squeals a shrill warning call, hoo-eek hoo-eek. The drake whistles an ascending, finch-like twee twee. Wood ducks are excellent swimmers and fast, agile fliers. Above open terrain they can wing along at up to 45 to 50 mph. In woodlands they twist and turn between the trees, moving their heads almost constantly in flight.
The wood duck feeds in thick marshes, brushy swamps and along woodland streams. A dabbler, it tips its head into shallow water and probes the bottom for vegetative parts and seeds of arrow arum, various grasses and sedges, smartweeds, burreed, pondweeds, duckweed and wild rice. It also eats grapes, berries, and nuts–acorns in particular—which are swallowed whole and crushed, inside the gizzard, into digestible bits. High-protein animal foods such as mollusks, insects and spiders comprise an important portion of the diet for egg-laying hens and young ducklings. In winter, wood ducks may turn to waste corn if natural foods are scarce.
Breeding occurs in late March and April, extending into July in the north. Most pairs form on the wintering range, following an intense courtship. The male preens behind his wings, spreading them to show off their iridescent sheen, he tucks in his chin, erects his crest, and fans his tail. He swims at the hen then circles her.
When the birds migrate north, the hen homes in on last year’s nest tree, or, if she is a yearling, on the same general locale in which she was hatched. The male sets up no actual territorial boundaries but will defend his mate from the attentions of other males. Several breeding pairs may share the same wetland. Nesting concentrations are largely determined by the availability of nest sites. The mated hen seeks out a cavity in a tree. The male follows her on these search flights, but the hen apparently picks the exact spot. Wood ducks prefer to nest in trees standing over water, but sometimes will settle for sites up to a mile away. They normally use natural cavities with entrances too small for raccoons to enter, often choosing excavations made by pileated woodpeckers. They also nest readily in man-made boxes.
The hen lays 8 to 15 eggs (one per day) in the bottom of the cavity, on accumulated wood chips covered with down from her breast. The eggs are light beige in color and unmarked. Incubation, by the female alone, starts with the last egg and takes about a month. Unlike most other male ducks, the drake woody stays with his mate well into her incubation. He has usually left the scene, though, by the time the eggs hatch.
All the eggs hatch on the same day. The hen usually keeps her brood in the nest overnight, and then in the morning she flies out and lands on the ground or water below where she begins calling softly. The day-old ducklings leap out of the nest to join her. They tumble down perhaps 60 feet, sailing like cotton puffs and usually land unharmed. The hen leads them to safety in thick marsh or swamp cover.
If a raccoon, snake, or squirrel destroys her first clutch, the female may lay a second. A few hens raise two broods in southern U.S. breeding range, but the vast majority raise only one.
Ducklings, and some adults, are preyed upon by mink, otters, raccoons, herons, hawks, owls, snapping turtles and predatory fish such as pike, bass and bowfin. In Maryland, scientists found that half of the young were killed in their first month. The brood begins to break up after six weeks or so, and the young can fly when two months old.
After leaving his incubating mate, the drake woodie joins other male wood ducks in the dense cover of a swamp or wooded pond. Here he molts into eclipse plumage: dull feathers resembling the drab plumage of a hen. Like all waterfowl, during part of the annual summer molt, wood ducks, both drakes and, later, hens, lose their wing flight feathers and cannot fly for a period of approximately one month. In late summer or early fall, a second molt begins, restoring the breeding or nuptial plumages.
Wood ducks migrate south for the winter. Some seek out common roosting and feeding sites, grouping in flocks of less than a hundred to several thousand. Pennsylvania band recoveries show homegrown woodies winter primarily in the Carolinas, and also along the Gulf Coast from Louisiana to Florida.
