Laura Erickson's For the Birds

(Recording of a Mallard)

Down in the central United States right now a female Mallard from Minnesota is trying to escape the onslaught of a pack of bachelor mallards. Although her chosen mate may eventually fend them off, chances are he’s too busy chasing down another female to even notice her situation. A 1987 study published in the journal of the American Ornithologists Union, titled “Multiple Paternity in a Wild Population of Mallards” found that fully 48% of all Mallard broods are fathered by more than one male—those little baby ducks you watch following their mothers this summer are as likely as not to be half-sisters and brothers rather than full-blooded siblings.

Mallards take their name from the old French word for masculinity, with the “ard” suffix having the same pejorative sense as the words drunkard, dullard, and sluggard. Drakes in captivity have been recorded breeding with every species of duck, including ones that are not in the same genus, or even in the same subfamily. Even in the wild there are countless cases of Mallard hybrids—ducks that look like patchwork quilts. The only other groups of birds with such frequent hybridizations are the hummingbirds and the birds-of-paradise—in all of these the males are far more brightly colored than the females, and the males don’t necessarily discriminate among females of different species—mate selection is the responsibility of the females. Interestingly, in all of these groups, the males don’t take any part in nest-building or the caring for the young.

Mallards, like just about all American ducks, select their mates each year on their wintering grounds. When it’s time to migrate, the females return to the area where they were hatched, and their mates follow. This system allows a great deal of genetic mixing–a male from Saskatchwan may pair with a female from Wisconsin down in Louisiana, while her brother may follow his mate up to Manitoba. This widespread mixing keeps the whole population fairly uniform—that’s why there are no subspecies of Mallards. This is different from the clannish Canada Geese, which usually mate with distant relatives—over time these clans become genetically isolated, explaining why there are so many subspecies of Canada Geese.

Mallards return in spring as the ponds open up, and quickly begin breeding. The female selects the nesting site and builds the nest, plucking soft down from her lower breast to line it. She lays an egg every day or two until she has a clutch of about 8-10. After she lays each of the first eggs, she leaves the nest for the day, covering the eggs with down for warmth and camouflage. She doesn’t begin incubating until the full clutch is laid, and so the babies all hatch out at the same time. She broods the babies for the first day, allowing them time to imprint on her quack before they leave the nest for good.

The babies follow her to a pond or lake much the way the young do in the children’s book, Make Way for Ducklings. They feed themselves a variety of small aquatic animals and especially plants, and grow quickly. The ones that survive snapping turtles, raccoons, foxes, bobcats, predatory fish like largemouth bass, and poisonous lead shot lurking in the bottom of just about every lake in the country face human hunters as they head south at the end of summer. The ones that survive pair up and start the whole process over again. Spring is the time of regeneration in the natural world, and no bird takes part in this annual ritual as lustily as the Mallard.

(Recording of a Mallard)

This is Laura Erickson, and this program has been “For the Birds.”