Wood Duck (Aix sponsa)
by Wanda Gorsuch

Common Names:

Woodie, summer duck, acorn duck, swamp duck, squealer, Carolina duck

The Wood Duck is considered one of the most beautiful ducks in North America, and rightly so. Reverence for their appearance goes all the way back to prehistoric Indians who regularly featured them on bowls and pipes.

Identification:

Few sights are more spectacular then a Wood Duck drake in full breeding plumage perched on a log and the females put other plain mottled hens to shame. Both sexes have a crested head. In males, the head has many hues of purple and green with two white lines running from the base of the bill and from the front of the eye to the crest. Chin and throat are white and the large eyes are red. A burgundy chest and purplish back and tail complete a handsome plumage. Hens have striking white rings surrounding their eyes on their sooty grey head. As in the male, chin and throat are white. Chest, sides and flanks are grey-brown and the belly is white. In flight, both sexes bob their heads, something that is seen in no other duck. Flying Wood Ducks can be confused with Wigeons, but their short, broad wings are very different from the longer, narrower wings of Wigeons.

Wood Ducks prefer to use freshwater wetlands that are associated with streams and rivers. Overhanging stream shoreline vegetation, channel border, back water and floodplain wetlands make up the backbone of the Wood Ducks habitat.

During breeding and brood rearing, Wood Ducks choose wetland areas with abundant plant and invertebrate food sources close to suitable nest sites. While migrating, they use similar habitat to breeding birds. In the winter months Wood Ducks like forested wetlands with oaks, hickories, red maple and ash. In general, winter habitat differs little from habitat used in during migration or breeding.

Wood Ducks eat a broad variety of foods. Their diet, similar to dabbling ducks, consists of seeds, fruits and aquatic and terrestrial invertebrates. Some of their favorites include acorns, smartweed, wild cherry and duck weed. Just before laying eggs and during laying, hens eat insects rich in calcium and protein – elements necessary for egg production. Late in the summer, Wood Ducks eat fruits and vegetative plant parts while in the winter months they consume more seeds, which are high in fat for gaining and maintaining weight.

Ducklings eat a wide variety of plant and animal matter like their parents. This way, they are able to ensure they receive all the necessary nutrients to grow and develop. Young ducklings consume mostly invertebrates in their first week of life and add more plant matter as they get older.

Reproduction:

Wood Ducks are cavity nesters, using preformed cavities in mature trees at least 30cm in diameter. They like to use nest sites close to or over-water that is good brood rearing habitat. Once a cavity is chosen, hens scrape the base material into a saucer shape. Hens will lay one white to tan glossy egg a day, only starting to incubate about 3-4 days before they are finished laying. The average number of eggs layed can range from 10 to 22. Parasitism (hens laying their eggs in other hens nests) is common. The Wood Duck is the only duck in North America that regularly produces 2 broods in 1 breeding season.

There are a number of nest predators that will happily eat Wood Duck eggs. These include raccoons, squirrels, woodpeckers, and rat snakes.

When the eggs hatch, hens incubate the ducklings for 24 hours until they are dry and fluffy. At that point, the hen leaves the nest and lands outside. Once she is sure there are no predators lurking, she calls the ducklings. The ducklings scramble up to the opening of the nest cavity and launch themselves out. Even with jumps over 60 feet high they still land safely! Once the brood has left the nest the hen leads them to water where they immediately begin looking for food. Ducklings stay with the hen until they are ready to fly at about 8 – 10 weeks of age.

Conservation and Management:

Wood Ducks are popular with hunters, making up more then 10% of the annual harvest in the United States. In fact, due to it’s popularity the Wood Duck faced extremely low population numbers in the early 1900’s, with some people even predicting that they would go extinct. However, with implementation of laws to restrict hunting, conservation programs and research as well as their ability to adapt to many different habitats Wood Duck numbers are now doing well in all parts of it’s range.

For more information on Wood Ducks:

Bellrose, F.C. 1976. Ducks, geese and swans of North America, 2nd edition. Stackpole Books, Pennsylvania.

Bellrose, F.C. and D.J. Holm. 1994. Ecology and management of the Wood Duck. Stackpole Books, Pennsylvania.

Hepp, G.R. and F.C. Bellrose. 1995. Wood Duck (Aix sponsa). In The Birds of North America, No. 169 (a. Poole and f. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and the American Ornithologists’ Union, Washington, DC.