The mallard is a large, heavy-looking dabbling duck, with a long broad bill, and one of our most familiar ducks. It frequently interbreeds with its closest relatives such as the American black duck, the pintail, or the gadwall (producing Brewer’s duck), resulting in offspring that are fertile. This is unusual but occurs because the mallard evolved rapidly and relatively recently. It has a very wide range and is highly adaptable, able to live anywhere there is a good supply of water and food. In recent years its population has been increasing so much so that in some areas it is considered invasive.
Breeding birds: 61,000-146,000 pairs
Wintering birds: 710,000
Family: Ducks, geese & swans
In breeding plumage, adult male mallards have dark grey upperparts with a black lower back and rump. The upperwing is grey with an iridescent purple-blue speculum with white edges, while the tail has white outer rectrices, a black centre, and black uppertail coverts.
The underparts are pale grey-brown with a purple-brown breast, the underwing is white and the undertail is black and white.
The head is metallic green with a purple iridescence, and there is a narrow white collar on the neck. The bill is yellow, the eyes are dark brown, and the legs and webbed feet are orange.
Female mallards have brown plumage overall with dark brown or black edges to the feathers giving a scaled effect, and brown ‘V’ shapes on the flanks. The tail is white, and they have the blue speculum with white edges.
The head is brown with a dark crown and eyestripe. The bill is grey with yellow or orange marks, and the legs and feet are orange.
In eclipse plumage, the male resembles the female, but is more rufous overall, and has a greenish-black cap and eyestripe, and a yellow bill.
Juvenile mallards are similar to females, but are darker and have more heavily streaked underparts. The young male has a brown bill.
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Mallards breed between February and June, and produce 1 clutch a season. They are generally monogamous although paired males will pursue females other than their mates. They may nest alone or in loose groups on dry land, often near water, on the ground hidden amongst vegetation, or in cavities in trees. In urban areas they have been known to nest in wood piles, old crows’ nests, haystacks, roof gardens, and balconies.
The female builds the nest alone which is a shallow bowl-shaped structure made from leaves and grasses and lined with feathers and down plucked from her breast.
Mallards lay 7-16 smooth, waxy, pale blue or pale green eggs which are incubated by the female alone for 28 days. Chicks are precocial and covered in brown down with buffy-white underparts, yellow cheeks and supercilium, and black eyestripe. They stay in the nest for about 10 hours to dry off and remain close to the nest for another 2 days. The female will then lead them to water, and she rears and cares for them until they are ready to fledge at about 50-60 days after hatching. They reach sexual maturity at 1 year.
Mallards are omnivorous, opportunistic feeders. They feed on seeds, aquatic plants, insects, larvae, dragonflies, crustaceans, molluscs, and worms, as well as occasionally small fish and amphibians. On land they eat corn, rice, and barley.
They feed by swimming along, both dabbling and up-ending in shallow water. They also graze on the ground in fields and woodland.
Mallards are found throughout the UK. Look out for them whenever there is water including wetlands, high moors, and coastal regions, as well as urban areas such as parks where there are ponds or rivers.
All species of domestic duck descend from the mallard except for a few breeds descended from the Muscovy duck. Wild mallards often mate with domestic ducks producing offspring that are fully fertile.
