The Tufted duck (Aythya fuligula) is a small diving duck found in northern Eurasia. Its scientific name comes from Ancient Greek word aithuia, an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin words fuligo "soot" and gula "throat".
Adult males of this species are all black in color except for white flanks and a blue-grey bill with gold-yellow eyes, along with a thin crest on the back of their heads. They have an obvious head tuft that gives these birds their name. Adult females are brown with paler flanks and are more easily confused with other diving ducks. In flight Tufted ducks show a white stripe across the back of the wing.
Tufted ducks breed throughout temperate and northern Eurasia. They occasionally can be found as a winter visitor along both coasts of the United States and Canada. These ducks are migratory in most of their range and overwinter in the milder south and west of Europe, Africa, Middle-East, Southern Asia and all year in most of the United Kingdom. Tufted ducks breed close to marshes and lakes with plenty of vegetation to conceal the nest. They are also found on coastal lagoons, shorelines, estuaries, sheltered ponds, slow-flowing rivers, tidal bays or freshwater wetlands.
Tufted ducks are social birds and often form large flocks on open water in winter. They are highly aquatic and spend most of their life in the water. These birds feed mainly by diving, but they will sometimes upend from the surface. They are generally active during the day but migrate by night. Tufted ducks communicate with each other vocally. The females' call is a harsh, growling "karr", mostly given in flight. The males are mostly silent but they make whistles during courtship based on a simple "wit-oo".
Tufted ducks are serially monogamous; pairs form during migration and stay together for one breeding season. The breeding season occurs from May to early August. Tufted ducks nest singly or in loose groups usually near water and among dense vegetation. Females build the nest on the ground and line it with down and vegetation. They then lay 8 to 10 olive-grey eggs and incubate them alone around 26-28 days. During this time males leave to form moulting flocks. Ducklings hatch fully developed and are able to follow their mother to learn how to feed soon after hatching. They fledge 49 to 56 days after hatching and become independent after another 21 to 56 days. Young Tufted ducks reach reproductive maturity and able to breed for the first time when they are 1 year old.
The biggest threat to Tufted ducks is habitat loss due to the destruction of wetlands for human development, drainage, pollution and oil spills. They also suffer from disturbance on inland water bodies and noises from urban development, hunting, and predation.
According to the IUCN Red List, the total Tufted duck population size is 2,600,000-2,900,000 individuals. The European population consists of 551,000-742,000 pairs, which equates to 1,100,000-1,480,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
Tufted ducks feed on many aquatic invertebrates, thus controlling their populations. In turn, these birds serve an important food source for local predators.