BIRDS
Status: Common, Native Migrant and Summer Resident

WOOD DUCK
(Aix sponsa)

Description

Wood ducks get their common name from their adaptation for living in the trees along streams and ponds. Their genus name,
Aix, from the Greek for water bird, is also a reference to the species' habitat. The name, sponsa , is Latin for bride, or
promised one, and refers to the spectacular plumage of this species.
 
Wood ducks are relatively small ducks, measuring from 15 to 21 inches (38-53 cm) in length, and weighing from 1 to 1.9
pounds (0.5-0.9 kg). The colorful male gives this species the title of the most beautiful duck in North America. His crest is
iridescent green in front and purplish in the rear. The sides of his head are purple, blue-green, and bronze. The bird's eyes
have a red iris and eyelids. The short bill has a black tip and ridge, white on the sides, and a red base bordered with a
narrow yellow line. The sides of the male's body are bronze, finely barred with black. The upper feathers are broadly tipped
black, and there is a white border along the green, purple, and bronze back and rump. The feet and legs are dull,
straw-yellow. Females are much more subdued in color. The crest of the female is brown, glossed with green. Her bill is
dark blue-gray and her eyes are brown. The female's back is olive-brown with a shimmer of iridescent green. The undertail
feathers are white, like the belly.

The species has a number of calls; the most familiar is the "hoo-eek" call given by the female as she takes off.
 
 
Distribution

Wood ducks are common migrants and summer residents in eastern South Dakota, especially along the James and the Big
Sioux rivers. They are uncommon in western South Dakota, and sporadic in the Black Hills. Numbers have increased in all
parts of the state since the 1930's. 
 

Natural History

Wood ducks winter in the southeastern United States, and begin returning to South Dakota during early April. When they
arrive, pairs of wood ducks search for suitable nesting cavities in trees. They prefer to nest in trees close to water, but will
use sites up to 1.3 miles (2 km) away. Where natural cavities are in short supply, artificial nesting boxes are commonly used.
The birds nest from April through June. The average clutch size is 12 dull white to brown white eggs. More than one female
may contribute to a clutch, resulting in a "dump nest." This behavior can create clutches of more than 60 eggs. These huge
clutches are rarely incubated , but successful dump nests of fewer than 30 eggs are common in nest boxes. The hen must
incubate the eggs for about 30 days until they hatch. At hatching, the ducklings have sharp claws that they use to climb to the
entrance of the nest, where they bail out of the nest cavity and, along with the hen, head for the water. Ducklings have been
known to jump 89 feet (27 m) to the ground without injury. The ducklings are ready to fly 6 to 8 weeks after hatching. Most
wood ducks begin their southerly migration out of South Dakota during the first half of October.

About 90% of a wood duck's diet is aquatic plant material. They are especially fond of duckweed, small flowering plants
that float on the water's surface. They also eat seeds and tree fruit such as acorns, nuts and berries. The remainder of their
diet consists of aquatic insects, minnows, frogs and tadpoles, and small salamanders. Raccoons are the most important
predator of wood duck eggs and incubating females.

Conservation Measures

Once thought to be in danger of extinction, wood ducks are now common due to careful management. Locally, wood duck
populations can be boosted through the use of nest boxes. But, care must be taken in box placement to prevent nesting
interference (dump nesting) and use of the boxes by squirrels. Nest box maintenance can be expensive and time consuming,
so management for natural cavities in trees should be encouraged. Preservation and proper management of trees along rivers,
streams, and wetlands are important. Federal, state and private agencies are keeping a close watch on the health of these
populations. Wood duck hunting is allowed by licensed hunters during a specified time of the year. The money derived from
license fees and taxes paid by the hunters is used to care for and protect wildlife populations.

Glossary

Clutch - the number of eggs laid in a nest at one time.

Incubate - to keep eggs in a favorable environment for hatching which is accomplished by the female sitting on the eggs in the nest.

Iridescent - displaying a changing combination of shiny, rainbow-like colors.

References
 

Bellrose, Frank C., 1976, Ducks, Geese, & Swans of North America, A Wildlife Management Institute Book; Stackpole
Books: Harrisburg, Pennsylvania, 17105.
SDOU, 1991, The Birds of South Dakota, NSU Press: Aberdeen, SD 57401.
Terres, John K., 1980. The Audubon Society Encyclopedia of North American Birds, Alfred A. Knopf, New York.

Written by:
Bill Schultze, Biologist, U.S. Fish and Wildlife Service, Sand Lake National Wildlife Refuge, Columbia, SD 57433. 1997.

Reviewed by:
Dr. Dan Tallman, Biology Professor, Northern State University, Aberdeen, SD.

Publication of the Wood Duck fact sheet was funded by the South Dakota Department of Game, Fish and Parks, Division of
Wildlife, Pierre, SD.