Mallard ducks are preyed upon by snapping turtles, raccoons, red foxes, black rat snakes, crows, largemouth bass, red-tailed hawks, bald eagles, ring-billed gulls and Norway rats. Mallard ducks are also threatened by human hunters.

The mallard duck's various natural predators are the most prevalent enemies that they face. However, human hunters remain a threat to mallards. Because mallards are the most widespread and abundant duck in North America, they are not subject to conservation laws, which would protect them from hunters. The number of mallard ducks varies from anywhere between five million to 11 million. Mallards account for approximately one out of three of every duck shot by hunters. Mallards are also threatened by unhealthy food, such as bread, fed to them by humans.

Beyond North America, mallards are also found in Asia and Europe. Generally they prefer fresh water, but they can also be found in saltwater. The male mallard is known as a drake and the female is called a hen. The male mallards, drakes, have the iconic coloring of green head and a white neckband that defines the mallard in popular culture. Mallards rarely dive underwater, generally spending their time near the surface. They can also graze on land and feed on plants. Mallard hens usually lay a dozen eggs with a month-long incubation period.