The mallard is a medium-sized waterfowl species that is often slightly heavier than most other dabbling ducks. It is 50–65 cm long – of which the body makes up around two-thirds – has a wingspan of 81–98 cm and weighs 0.7–1.6 kg . Among standard measurements, the wing chord is 25.7 to 30.6 cm , the bill is 4.4 to 6.1 cm , and the tarsus is 4.1 to 4.8 cm .
The breeding male mallard is unmistakable, with a glossy bottle-green head and a white collar that demarcates the head from the purple-tinged brown breast, grey-brown wings, and a pale grey belly. The rear of the male is black, with white-bordered dark tail feathers. The bill of the male is a yellowish-orange tipped with black, with that of the female generally darker and ranging from black to mottled orange and brown. The female mallard is predominantly mottled, with each individual feather showing sharp contrast from buff to very dark brown, a coloration shared by most female dabbling ducks, and has buff cheeks, eyebrow, throat, and neck, with a darker crown and eye-stripe.
Both male and female mallards have distinct iridescent purple-blue speculum feathers edged with white, which are prominent in flight or at rest but temporarily shed during the annual summer moult. Upon hatching, the plumage of the duckling is yellow on the underside and face (with streaks by the eyes) and black on the back (with some yellow spots) all the way to the top and back of the head. Its legs and bill are also black.
As it nears a month in age, the duckling’s plumage starts becoming drab, looking more like the female, though more streaked, and its legs lose their dark grey colouring.Two months after hatching, the fledgling period has ended, and the duckling is now a juvenile.
Between three and four months of age, the juvenile can finally begin flying, as its wings are fully developed for flight (which can be confirmed by the sight of purple speculum feathers). Its bill soon loses its dark grey colouring, and its sex can finally be distinguished visually by three factors: 1) the bill is yellow in males, but black and orange in females; 2) the breast feathers are reddish-brown in males, but brown in females; and 3) in males, the centre tail feather (drake feather) is curled, but in females, the centre tail feather is straight.
During the final period of maturity leading up to adulthood (6–10 months of age), the plumage of female juveniles remains the same while the plumage of male juveniles gradually changes to its characteristic colours.This change in plumage also applies to adult mallard males when they transition in and out of their non-breeding eclipse plumage at the beginning and the end of the summer moulting period.The adulthood age for mallards is fourteen months, and the average life expectancy is three years, but they can live to twenty.
Distribution and Habitat
The mallard is widely distributed across the Northern and Southern Hemispheres; in North America its range extends from southern and central Alaska to Mexico, the Hawaiian Islands, across the Palearctic,from Iceland and southern Greenland and parts of Morocco (North Africa) in the west, Scandinavia and Britain to the north, and to Siberia, Japan,and South Korea. Also in the east, it ranges to south-eastern and south-western Australia and New Zealand in the Southern hemisphere. It is strongly migratory in the northern parts of its breeding range, and winters farther south.
It is found in Bulgaria throughout the year, but is most numerous during migrations and in winter. An average of about 100,000 ducks winter here. It is most common in the plains of the country, along the Danube and along the Black Sea coast. Tolerates the closeness of man. The green-headed duck is the most numerous species of duck in Europe and in Bulgaria.
The mallard inhabits a wide range of habitats and climates, from the Arctic tundra to subtropical regions.It is found in both fresh- and salt-water wetlands, including parks, small ponds, rivers, lakes and estuaries, as well as shallow inlets and open sea within sight of the coastline. Water depths of less than 0.9 metres are preferred, with birds avoiding areas more than a few metres deep.They are attracted to bodies of water with aquatic vegetation.
The mallard is omnivorous and very flexible in its choice of food. Its diet may vary based on several factors, including the stage of the breeding cycle, short-term variations in available food, nutrient availability, and interspecific and intraspecific competition.The majority of the mallard’s diet seems to be made up of gastropods, insects (including beetles, flies, lepidopterans, dragonflies, and caddisflies),crustaceans, worms,many varieties of seeds and plant matter, and roots and tubers.During the breeding season, male birds were recorded to have eaten 37.6% animal matter and 62.4% plant matter, most notably the grass Echinochloa crus-galli, and nonlaying females ate 37.0% animal matter and 63.0% plant matter, while laying females ate 71.9% animal matter and only 28.1% plant matter. Plants generally make up the larger part of a bird’s diet, especially during autumn migration and in the winter.
Mallards usually form pairs (in October and November in the Northern Hemisphere) until the female lays eggs at the start of the nesting season, which is around the beginning of spring. At this time she is left by the male who joins up with other males to await the moulting period, which begins in June (in the Northern Hemispher). The breeding period in Bulgaria is from the end of March to the end of June.
Nesting sites are typically on the ground, hidden in vegetation where the female’s speckled plumage serves as effective camouflage, but female mallards have also been known to nest in hollows in trees, boathouses, roof gardens and on balconies, sometimes resulting in hatched offspring having difficulty following their parent to water.
Egg clutches number 8–13 creamy white to greenish-buff eggs free of speckles. They measure about 58 mm in length and 32 mm in width. The eggs are laid on alternate days, and incubation begins when the clutch is almost complete. Incubation takes 27–28 days and fledging takes 50–60 days. The ducklings are precocial and fully capable of swimming as soon as they hatch. However, filial imprinting compels them to instinctively stay near the mother, not only for warmth and protection but also to learn about and remember their habitat as well as how and where to forage for food. When ducklings mature into flight-capable juveniles, they learn about and remember their traditional migratory routes (unless they are born and raised in captivity).
In cases where a nest or brood fails, some mallards may mate for a second time in an attempt to raise a second clutch, typically around early-to-mid summer. In addition, mallards may occasionally breed during the autumn in cases of unseasonably warm weather.
During the breeding season, both male and female mallards can become aggressive, driving off competitors to themselves or their mate by charging at them. Males tend to fight more than females, and attack each other by repeatedly pecking at their rival’s chest, ripping out feathers and even skin on rare occasions.
Least Concern (IUCN 3.1)