by Janice Welsh
If all the species of ducks in Minnesota held a family reunion, it would be a crowded place. Ducks make up the largest group of waterfowl, with 22 species nesting in Minnesota or visiting in various seasons.
The way ducks feed divides them into two groups: dabblers and divers.
Dabblers are built with their legs close to the middle of their bodies. This helps them to walk well on land and to tip up like bobbers to feed on underwater plants.
Diving ducks are like submarines, built for swimming underwater for long distances in search of aquatic invertebrates and plants. Divers' wings are short to create less drag while swimming underwater.
Other ducks seen in Minnesota, though less often than those shown here, include the harlequin, Barrow's goldeneye, white-winged scoter, and surf scoter.
As ice begins to cover up duckweed, water bugs, and other foods on lakes, ponds, and rivers, ducks migrate to open water.
Some species, such as mallards and wood ducks, travel to the southern United States. Blue-winged teal go as far south as Cuba and parts of northern South America. Hardy diving ducks, such as common goldeneyes and oldsquaws, cruise the open water of the Great Lakes and coasts during the winter. Most canvasbacks that fly through Minnesota from Canada go on to the Chesapeake Bay, the eastern Great Lakes, or the Gulf of Mexico.
Dabbling ducks strain food from a lake by drawing water from the surface and squirting it out. Comblike structures on the edge of the bill, called lamellae, trap small water animals and plants. This is called filter feeding. Diving ducks use their lamellae to catch and hold freshwater shrimp and other invertebrates. Mergansers belong to a special group called fish ducks. They have lamellae that are toothlike and enable them to catch and hold slippery fish.
Webbed feet help ducks to swim. They even help them brake for a landing. Even the coldest water doesn't bother ducks. They have a network of blood vessels in their legs that removes the heat from the blood just before it travels down to the feet and warms it up to go back to the heart. While we'd grab our wool socks, ducks don't seem to mind that their feet are only a few degrees warmer than the chilly water.
A duck waterproofs its feathers with oil from a gland on its back. It carefully preens its feathers so that they lie in their proper places and stay free of dirt and parasites. A thick layer of down feathers next to the duck's skin works like a jacket, keeping warm air in and cold air out.
Shallow ponds are especially important in early spring because they melt before deeper water does. They contain a tremendous amount of high-protein invertebrates for ducklings to eat so they grow big in time to fly south. Deeper wetlands are also important, because they provide feeding and nesting areas even in dry years.
Many ducks select a mate during the winter months and travel together to wetland nesting grounds in the early spring.
The hen usually chooses a spot to nest. Hens of some species, such as mallards and wood ducks, often return to the place where they were hatched and raised. This is called homing.
In the case of mallards, the hen lays one egg each day until she has laid her entire clutch of eight to 14 eggs. The male leaves her as she begins incubation. She will leave the nest only for a short time each day to feed and drink. After 28 days of incubation, the eggs hatch. Then the hen leads the young away to water, never to return to the nest again that year.
Sometimes people have to help ducklings across busy roads or fences by placing the young in a box and having the hen follow them to a safe location. Single or orphan ducklings can be placed in wetlands with other broods about the same age.
Green Wings, sponsored by Ducks Unlimited, offers memberships and a magazine for young people.
Minnesota Waterfowl Association has programs for young people, including Woody Camp, a weeklong hunting and duck ecology camp.
Woodworking for Wildlife by Carrol Henderson has plans for building nest boxes for cavity-nesting ducks.
Jan Welsh, author of this article, is coordinator of the DNR's Project WILD, a program for schools.
A complete copy of the article can be found in the March-April 1998 issue of Minnesota Conservation Volunteer, available at Minnesota public libraries.