When I think of Chesapeake summers, one thing comes to mind: blue crabs. When I think of autumn, I think of Canada geese. But it’s not just geese making their way to the Bay. As the days shorten and temperatures drop, about 20 species of swans, geese and ducks journey from northern breeding grounds to overwinter here.

About 1 million waterfowl, roughly one third of all waterfowl wintering along the Atlantic Coast, are lured from Alaska, Canada, north central United States and New England to the rivers, creeks and wetlands of the Chesapeake Bay in search of habitat and food.

Swans are the largest of these waterfowl and the tundra swan travels the farthest — more than 4,000 miles — to winter primarily on the Eastern Shore of the Chesapeake. These large white birds are easily recognized by their black bills and straight necks. Tundra swans often flock on shallow ponds.

Another swan, the mute swan, is a nonnative, invasive bird from Europe. The mute swan competes with native waterfowl for food and habitat. Orange bills and S-shaped necks distinguish the mute swan from our native tundra swan.

Autumn would not be complete without migrating geese in sky. Constant honking signals the arrival of the familiar Canada goose, with its black and white head, brown back and pale breast.

A favorite quarry of hunters and bird watchers, Canada geese feed in wetlands or cultivated fields. A lesser-known visitor is the snow goose. As its name implies, the snow goose is white except for black wingtips and pink feet and bills.

The small, black Atlantic brant also winters here.

Ducks are divided into two groups by their method of feeding: dabbling and diving.

Dabbling ducks traditionally feed by straining food from the water’s surface or by submerging their heads while their tails remain out of the water.
Characteristics common to dabbling ducks include legs positioned toward the middle of the body and colored wing patches (specula). Males are usually brightly colored while females are drab.

Plants make up most dabblers’ diets. Dabblers take flight by leaping from the surface of the water and can be found on rivers and close to shorelines.

The most common dabbler is the mallard duck. The male has a dark green head while the female is dusky brown. Another dabbler is the black duck. Both male and female black ducks look similar to mallard hens, only darker. These two species often interbreed.

Other dabblers include the American wigeon, green-winged teal, northern pintail (The male has long black tail feathers.) and northern shoveler (named for its large spatula-like bill).

The legs of diving ducks are located to the rear of the body. This makes walking on land difficult. Diving ducks swim underwater, pursuing fish or searching the bottom for roots and seeds of bay grasses and small animals.

They must run along the surface of the water to take flight. Diving ducks can be further separated into bay ducks and sea and river ducks.

Bay ducks feed in shallow water (less than 20 feet), foraging for plant and animal foods. Males have contrasting head and body colors while the females are dark or brown.

The most famous bay duck is the canvasback, with its sloping black bill, red eyes and head, and white back. Canvasbacks congregate on the water in large flocks known as rafts.

Redhead ducks are similar to canvasbacks but with shorter bills and round heads. Once abundant on the Chesapeake Bay, redhead ducks feed solely on submerged aquatic vegetation. Most redheads now winter farther south, where plants are more prevalent. Other bay ducks include the greater and lesser scaup.

Sea ducks are commonly found in the deeper, open waters of the Bay. Most sea ducks feed primarily on animals such as crabs, clams and barnacles.

The oldsquaw sports contrasting brown and white colors and long tail feathers. Sloping foreheads identify the white-winged, surf, and black scoter.

The ruddy duck, like the canvasback, masses in rafts. The bufflehead is a small black and white duck. Like its name implies, the male of this duck has an easily identified puffy head.

The red-breasted, hooded, and common merganser are river ducks. Mergansers prey on fish caught in fresh and brackish water. They are easily identified by long, thin, serrated bills and crested heads.

Those who don’t live on the water and may never see this variety of species should note that National Wildlife Refuges provide some of the best opportunities to observe and photograph waterfowl and other wildlife. National Wildlife Refuge Week, October 5–13, is timed to coincide with the annual fall migration, when bird watching should be at its best.

In Delaware, visit Bombay Hook NWR in Smyrna or Prime Hook in Milton.

In Maryland, stop by Blackwater NWR in Cambridge, Eastern Neck NWR in Rock Hall or Patuxent National Wildlife Visitor Center in Laurel.

In Virginia, visit Back Bay NWR in Virginia Beach, Chincoteague NWR in Chincoteague; Eastern Shore of Virginia NWR in Cape Charles, Potomac River NWR Complex in Woodbridge or the Rappahannock River Valley NWR Complex in Prince George.

A fall trip to any of these refuges is a real treat. For information about National Wildlife Refuges or a copy of the Refuge System Guide, call 1-800-344-WILD (800-344-9453) or visit http://refuges.fws.gov.