gastropod molt hybridize

The familiar mallard, Anas platyrhynchos, is an extremely common dabbler duck in the Chesapeake Bay region but can be found in abundance all over the world—throughout Asia, Africa, the northern hemisphere and in South America. In the Bay watershed, this is the most widespread inland duck. Its preferred habitat includes marshes, estuaries, ponds, marinas and harbors. It adapts easily to contact with humans and can even be tamed.

• Mature mallards in this region reach a length of 24 inches.
• Males and females differ in coloration: the male has a gray body and wings, with its head and neck a familiar deep iridescent green. The chest has a purple tinge with a white ring. The tail is also white, and its bill is yellow.
• The female mallard is a drabber brown with dark brown back, no white in her tail and a pale orange bill and legs. Males are generally silent, while females quack.

Mallard photo by Russ Mader

The mallard prefers wetland areas where it can consume quantities of submerged aquatic vegetation and aquatic invertebrates. They eat worms, gastropods and arthropods, and will eat grain from croplands or other foods generated by humans, including the occasional handout.

Life Cycle

• Females breed after a year of age; however, older females appear to have broods with lower duckling mortality than younger breeding females.
• Mallard pairs may form in October and continue through the winter and into March.
• Males remain with the females until incubation begins to occur, then leave to flock with other males for the annual molt.
• Females lay as many as 13 olive-green eggs in a down-lined ground nest located near water.
• Hatchlings emerge in about 28 days, after which the hen brings them to the water’s edge and leads them to swim.

In northern areas, once breeding has occurred, mallards migrate in flocks to southern areas, and remain their through the next breeding season. In the Chesapeake Bay watershed, mallards are generally year-round residents.

• This species is the most common and widespread waterfowl species in the world, and millions are taken each year as game. The loss of habitat, however, is considered a much greater threat to the health of the mallard population than predation by humans.
• More than 10 million mallards are thought to live in North America alone.
• The mallard is the ancestor of the common white domestic duck. Today mallards continue to hybridize with other wild species and domestic ducks, producing complex variations in color.

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Last modified: 11/30/2005