The mallard duck can be found throughout temperate and tropical zones and belongs to the Anatidae family. The male ducks (drakes), are distinguished by the green plumage on their heads and their grey wings and belly, while the females (hens), are mostly brown with speckles. Both male and female ducks have an area of white-bordered black and sometimes blue feathers towards the back of their wings. The ducks can grow up to between 50 and 65 centimeters, have a wingspan of 81 to 98 centimeters and can weigh up to 1.58 kilograms. Mallard ducks are a common feature of wetlands where they forage for plants and small invertebrates such as insects, molluscs, crustaceans, worms, and occasionally amphibians and fish.
Some populations of mallard ducks are sedentary or dispersive, while others are fully migratory. Breeding usually occurs between March and June. Males will gather in groups and moult while females are incubating. Nesting sites are usually close to the water and may be within vegetation on the ground, under fallen dead wood, on tree stumps or in tree cavities, sometimes up to 10 meters in height. Females may lay between 8 and 13 eggs, which take 27 to 28 days to incubate. When they hatch, ducklings are fully capable of swimming, and may take 50 to 60 days to learn how to fly. They are a sociable species and live in flocks which can count up to several hundred individuals. Mallard ducks can be found in flooded swampy woodlands, seasonal flood lands, wet grassy swamps and meadows, open waters with mudflats, banks or spits, irrigation networks, reservoirs, canals and sewage farms. In Mauritius, they are most commonly found in coastal wetlands. They may tolerate brackish water as long as there is submerged, floating or emergent riparian vegetation. These ducks feed by dabbling in the water and grazing on land.
The species is classified as ‘Least Concern’ in the IUCN Red List of Threatened species. Mallard ducks are a very adaptable species, which has led them to be considered as an invasive species in some regions where they may outcompete more localized sensitive waterfowl. Non-migratory mallards may interbreed with indigenous wild ducks of closely related species, threatening the survival of indigenous waterfowl through hybridization. Despite their adaptability, mallard ducks are threatened by habitat degradation, loss and pollution. They are a commonly hunted species for sport and commercial use. Mallard ducks benefit from conservation actions on wetlands.
The mallard duck is the ancestor of the domesticated duck.