When one thinks of Chesapeake Bay waterfowl, Canada geese and mallards probably come to mind. But those who frequent the open water and marshes in the winter may also see canvasbacks, buffleheads and tundra swans.

Explore the forested shorelines of Chesapeake rivers during warmer months though, and one is likely to encounter one of the most beautiful ducks in North America: the wood duck.

The wood duck's beauty is reflected in its scientific name, Aix sponsa, from the Greek word "aiks" for water bird and Latin word "sponsa" for betrothed. This name refers to plumage so striking that the wood duck looks like it is dressed for a wedding.

Early colonists aptly called them summer ducks. They have also been known as the Carolina duck, because of where it was first described; the swamp duck, because of its preferred habitat; and the acorn duck after one of its favorite foods.

Both drakes (males) and hens (females) have crested heads ending in hood-shaped manes. The drake's head is iridescent green, blue, purple, black and white. Its eyes and eyelids are red, and throat and breast are brown with lighter brown on sides and bellies.

Hens, like most female birds, are duller in plumage. Their heads and necks are gray, and bodies brown. Sporting a smaller mane, the female has a white teardrop patch around her eye.

The call of the male wood duck is a delicate squeak, while the female has a much harsher call. The female's alarm call is a loud "weeek."

Wood ducks, so named because they nest in tree cavities, are found in wooded swamps and woodlands near ponds, streams and rivers. Their range nearly coincides with the United States borders and at one time the wood duck was considered as a possible national symbol.

Courtship and pairs begin to form in autumn and into spring. Nesting begins between mid-January in the Deep South, and early April in the northern part of its range. The wood duck is affiliated with old growth timber that provides a diversity of cavities high up in the trees.

The female builds her nest in a tree cavity, usually 30 feet or more above the ground or water. The nest cavity is lined with down and wood chips. Wood ducks often reuse the same nest year after year. Some wood ducks double brood, meaning they nest twice in a single year. They are the only North American waterfowl to do so.

Ducklings are born precocial, meaning they are mobile, and downy, and can find their own food. They remain in the nest only 24 hours after hatching. The hen calls them out of the tree cavity from the water or ground below. Using their sharp clawed feet, the nestlings are able to climb out of the cavity and leap down, sometimes from as high as 60 feet, to land next to the mother hen waiting below. The ducklings will never return to their nest again and are able to fly 56-70 days after hatching.

Eggs are preyed upon by raccoons, opossums, snakes and birds. Flightless ducklings are also preyed upon by snapping turtles, mink, large fish and snakes.

At one time, unregulated hunting took its toll on the wood duck. Large roosts of migrating wood ducks made them an easy target for market hunters, who decimated wood ducks and other waterfowl to satisfy the demand for game meat by grocers, restaurants and hotels.

Hunting and loss of both wintering and nesting habitat to poor forestry practices as well as agricultural, residential and industrial development almost caused the wood duck's extinction around the turn of the century.

In 1918, the Migratory Bird Treaty Act outlawed the market hunting of migratory waterfowl. Soon after, both the United States and Canada banned the taking of wood ducks. To address the loss of natural tree cavities for nesting, state game departments, sportsmen's organizations and federal agencies began installing nesting boxes, which wood ducks readily use. In 1942, hunters in the Atlantic and Mississippi Flyways were allowed take one wood duck per day.

Conservative bag limits and artificial nesting sites greatly aided the comeback of the wood duck. But like all wildlife, the wood duck's continued survival depends upon the conservation of habitat, in this case the riparian forests along streams, rivers and shorelines.

Riparian forests not only provide homes for wood ducks and other wildlife, but also protect stream banks and improve water quality. Forest products, such as wood and paper, are important to many local economies. Finally, forests provide a place for recreational activities like hiking, camping, hunting and fishing. They offer us a place to experience the beauty of nature; the beauty of wood ducks.

The second Saturday in May is International Migratory Bird Day. To find out about local IMBD activities and celebrations, visit: www.birdday.org/.

May is also American Wetlands Month. To find out more about wetland activities and celebrations, visit: http://water.epa.gov/type/wetlands/outreach/index.cfm.