The most familiar and widely distributed of the dabbling ducks, the Mallard is often the standard against which all other ducks are compared. The male's characteristic and conspicuous green head, gray flanks, and black tail-curl make it among the most easily identified ducks. Once known as the "wild duck" in England, reflecting its status as a highly prized game bird, the Mallard has long been shot for sport and meat throughout the Northern Hemisphere. The Mallard is the source of all domestic ducks, except the Muscovy Duck (Cairina moschata). Feral populations composed of mixtures of both wild and domestic Mallards inhabit and breed in urban areas throughout the world, where they habituate to humans who feed them.
In North America, the Mallard is the most abundant duck species. Its success in the wild reflects its adaptability to varied habitats, its hardiness in cold climates, its catholic food tastes, and its tolerance of human activities. The Mallard can be found wintering as far north as conditions permit, as long as there is open water and access to food. As a breeder, it ranges from California to Alaska and across the central plains to the Atlantic Coast, nesting in marshes, farmlands, forests, and urban parks. The bulk of the Mallard's diet outside the breeding season consists of seeds of both native wetland plants and agricultural crops. Although the Mallard is the most heavily hunted duck species in North America, its populations have remained more or less steady. Wildlife managers carefully monitor and manage populations and their habitats to ensure the continued benefit of the Mallard and associated wetland species.
The taxonomy of the Mallard and close relatives is complex and there is disagreement on how to treat some taxa. In this account, we follow the eBird/Clements Checklist (1); see 2018 Updates and Corrections, which separates the Mexican Duck (Anas diazi) from the Mallard.