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In 1941, Robert McCloskey wrote “Make Way for Ducklings,” a beguiling Caldecott medal-winning children’s story in which Mr. and Mrs. Mallard search historic Boston for a safe place to nest.

Mr. McCloskey’s artistic license on the mallard lifestyle does not diminish the book’s charm. Mallards are often a child’s first friendly animal experience, nurturing the connection between humans and wildlife. An excursion to Northwestern’s lagoon, Lovelace Park or Wilmette Harbor to feed the ducks is a typical family outing.

Mallards (Anas platyrhynchos) are the most wide-ranging and populous ducks on the planet and are the ancestors of most domestic ducks. They are medium-sized, weighing about two pounds, and are social and noisy. They are strong flyers that spring up into the air in a single burst. They prefer shallow fresh water ponds or wetlands.

As dabbling ducks, they are comical to watch as they feed, head in the water, rump sticking straight up in the air, as opposed to diving ducks that disappear underwater and reappear unexpectedly.

The female mallard gives the familiar “quack;” the male has a rasping nasal sound in addition to his whistling call during courtship. If mallards were uncommon, people would rave about the beauty of the male. Unfortunately, he is considered “just a mallard.”

A mallard’s compact body and insulating feathers help it conserve heat in water and winter. Its legs, like those of other dabbling ducks, are set just back of mid-body, helping it navigate on land.

Its wide, webbed feet are useful not only for swimming but also act as a rudder when flying. Its long, wide, flattened bill, rounded at the tip, has a “nail” at the end for scooping food from water and has soft edges for feeling for food. The “lamellae,” comblike structures that line the inside edges of its bill, strain the mud for food such as seeds and bugs.  Mallards are opportunistic feeders and will devour plants, insects, seeds, acorns, small amphibians, frogs, even small fish.

Mallards court in groups during winter, and males will sometimes perform intricate simultaneous movements. Dr. Charles W. Townsend describes a courtship ritual in “Bent’s Life History” (1916): “When the mallard drake courts, he swims restlessly about following or sidling up to a duck. She may lead him quite a chase before she vouchsafes to acknowledge his presence, although he is continually bowing to her, bobbing his head up and down in nervous jerks so that the yellow bill dips into the water for a quarter of its length and comes up dripping. He also rears himself up in the water and from time to time displays his breast. She occasionally turns her head to one side and carelessly dabbles her bill in the water, but sooner or later, if all goes well, she begins to bow also, less vigorously at first: not touching the water at all: and to the empty space in front of her. [sic] Suddenly she turns and the pair bow to each other in the same energetic nervous jerks, and, unless a rival appears to spoil the situation, the drake has won his suit.”  

Mallard pairs are monogamous for the season but males have extra-pair interests.

The female chooses a well-camouflaged upland nest site, often one where she has succeeded before. She builds the nest in a depression lined with leaves, grasses, and her own down and breast feathers.  

The male defends a small nearby “pair pond” that includes open water, thick cover, and open land for preening and loafing. The female lays eggs in early morning, an average of a dozen. She leaves the nest twice a day to feed, carefully covering the eggs while she is gone.

When the last egg is laid after about 26 days, the female dismisses her mate and incubates the eggs on her own.

The now superfluous male will fly to a well-hidden bachelor pad and molt, leaving him flightless. Mallards molt their feathers twice a year, the new ones coming in and pushing out the old.

The new feathers grow quickly each day. They are heavy and blood-filled. When their full length is reached, blood stops flowing to them and they become hollow and light.  

During this molt, the male is in “eclipse” plumage and will resemble the brown female. In fall, he will emerge with his arresting breeding plumage and will be able to fly. His head will be brilliant iridescent green, accompanied by a narrow white neck ring and a chestnut-brown breast. His back and wings will be brownish gray with light grey underneath. His tail will have white outside and two black feathers in mid-tail that curl up. His bill will be a strong yellow, his feet orange-red.  

When ducklings hatch, they are precocial, that is, they can feed themselves almost immediately. They are covered with down and can walk and swim but cannot fly. Within 24 hours, the female leads her ducklings to water in the familiar straight line. They stay together for about two months, often moving from pond to pond.

When the ducklings are able to fly, the hen, her parental responsibilities over, leaves for her flightless molt. Her nutrition has been seriously depleted and she is very vulnerable. If she feeds well and survives, she will emerge with her same mottled light brown color, the same black marks down the center of her orange bill, a dark crown and a dark eye-stripe.

Both sexes have an iridescent blue-purple speculum patch on the wing.  (Both sexes also molt in spring but retain their flight and tail feathers.)

Many mallards migrate starting in September but others overwinter in the Chicago area wherever there is open water.

They can stand on ice because their feet are kept above freezing through a sort of heat exchange system. Through their arteries and veins, cool blood is circulated from feet to body where it is warmed before returning to their feet. On the ice, they will stand with one foot under feathers or lie down, their feathers covering their legs and feet.  

Overwintering ducks provide excellent opportunities to watch courtship in action.

Libby Hill

Libby Hill is the author of "The Chicago River: a Natural and Unnatural History. She has been writing about birds and trees and Evanston's natural history for the Roundtable since 2004.