Living environment and biology of the species
It is a species found in a variety of habitats, from tundra to subtropical, with slow-flowing or still, relatively sheltered waters, estuaries and deltas, lagoons, shallow water sea coasts, lakes, rivers, ponds and puddles, especially in shallow waters with submerged or floating vegetation. Generally avoids deep or exposed waters.
Predominantly migratory species, but some populations are sedentary. Wintering and nesting territories overlap for many populations.
It is an omnivorous and opportunistic species. Food consists of plant debris, leaves, tubers, rhizomes, roots, seeds, insects and their larvae, snails, crustaceans, tadpoles and even small fish. It is a very active species at night. They gather in large groups outside the nesting season. Migrates in flocks. In spring migration flocks are predominantly pairs. In February the pairs begin to look for nesting sites.
Pairs nest separately, but may sometimes form colonies. They nest on the ground in dense vegetation, under boulders, in overhangs or at the base of bushes. Nesting is also common on plains or in reeds. After mating, the male leaves the female and joins other males, waiting for the breeding season, which begins in June. Sometimes they may stay with the female for a second breeding when the first nest has been destroyed. Laying of the clutch takes place from February (in warmer areas). The clutch consists of 8-14 greenish or blue-green eggs, which are incubated for 27-28 days. If the first clutch is destroyed, a second clutch is laid. The breeding period is very demanding for the female, as she invests almost half of her body weight in egg production. For this reason, quiet and feeding areas are very important for the conservation of this species. The chicks are nidifugous and follow the female into the water immediately or a few hours after hatching. They can feed on their own, but depend on parental care until they are 7-8 weeks old, when they become able to fly. Other species of nesting parasitic ducks, such as the brown-headed duck, the widgeon, the mottled duck, the red duck or the spoonbill, may lay eggs in the nests of large ducks. In these cases of nest parasitism, the female mallard may hatch the entire clutch, or remove the eggs of a different colour. It often happens that the whole nest is abandoned, especially if the parasitism occurs during the laying period.
