Common Names: Greenhead (drake), green-headed mallard (drake), susie (hen), gray duck (hen), northern mallard
Perhaps one of the most widely recognized ducks in North America, the Mallard remains a favorite for sport and meat. As one of the most abundant duck species, it is the source of all domestic ducks in North America, except the Muscovy.
Mallards are large, stocky dabbling ducks. Adult males in full breeding plumage are hard to miss with their striking dark green head, narrow white neck ring, brown chest white outer tail-feathers and recurved black central tail feathers. In non-breeding plumage (late summer), males resemble females, but are larger, have solid dark green crown and solid brown breast.
Females are more drab, a protection against predators when they are sitting on a nest. Female plumage has a streaky pattern in buff, white, gray or black through their brown feathers. They have a prominent dark eyeline and heavy orange bill.
Both drakes and hens have a blue/violet speculum bordered by a white strip. As well, in flight both sexes can been seen to flash a white underwing.
Mallards are extremely adaptable and use a wide variety of habitats. During breeding season, Mallards will nest in many different places that provide cover, including grasslands, marshes, bogs, riverine floodplains, dikes, road ditches, pasture, cropland, shrubland, fencelines, rock piles and forests.
When migrating, Mallards typically use shallow wetlands (e.g. marshes, small ponds, flooded agricultural fields). Hunting pressure can also affect habitat use. In autumn months, staging ducks will often congregate on grain fields.
Across their winter range, Mallards only require a ready food source and small area of open water.
Mallards are omnivorous and tend to eat anything that comes their way. During breeding season, a time when protein is needed for breeding and egg development, Mallards concentrate on animal foods such as midge larvae, dragonfly and caddis larvae, snails, freshwater shrimp and terrestrial earthworms. Outside of breeding season, Mallards eat mostly seeds from moist-soil plants, acorns, aquatic vegetation and corn, rice, barley and wheat from agricultural crops.
Most Mallards form pair bonds on the wintering grounds. As soon as open water appears on the breeding grounds, pairs arrive. Hens start selecting a nest site in about 5 – 10 days after establishing their home range.
Once a hen selects a suitable site, usually on the ground near water, they makes a shallow bowl by digging into the ground with their feet and rotating on their breast. Hens don’t carry material to the nest, but pull in what they can reach with their bill while on the nest. As laying and incubation progresses, hens will add more vegetation and down from their breast.
Incubation starts during the egg laying period and gradually gets longer with each egg laid. Average clutch size for a Mallard is about 8 creamy to gray or greenish buff eggs. Eggs hatch after about 23 – 30 days. 24 hours before ducklings start to crack their shell (pipping), they begin to vocalize and the hens will respond with quiet calls. The first egg laid is the first egg to hatch.
Ducklings usually leave the nest with the hens about 13 – 16 hours after hatching, once their down is dry. Only hens care for the ducklings. They lead their brood to nearby water where ducklings feed themselves. Hens usually stay with their broods until they can fly (52 – 70 days).
Conservation and Management
Mallards are not threatened or endangered in any part of their range. Today, much of waterfowl management is based on Mallard populations. Mid-continent Mallard populations are used for Adaptive Harvest Management (USFWS) where computer models take environmental changes and biological responses over a year to predict populations sizes for waterfowl. AHM is currently being modified to incorporate information on other waterfowl breeding populations.
Sources of Information
Bellrose, F.C. 1976. Ducks, geese and swans of North America, 2nd edition. Stackpole Books, Pennsylvania.
Drilling, N., R. Titman and R. McKinney. 2002. Mallard (Anas platyrhynchos). In The Birds of North America, No. 658 (A. Poole and F. Gill ed.). The Birds of North America, Inc., Philadelphia, PA.