The tufted duck (Aythya fuligula) is a diving duck species belonging to the family Anatidae. It is a medium-sized duck, with a length ranging from 42 to 49 cm (17 to 19 in) and a wingspan of 71 to 82 cm (28 to 32 in). The male has a black head with a distinctive white tuft on the back of the head, while the female has a brown head and a white patch around the eye. Both sexes have a black back and white underparts, and a long, pointed bill.
The tufted duck is found in freshwater habitats across Eurasia and North America. It is a migratory species, and winters in southern Europe, North Africa, and Asia. The tufted duck is an omnivorous feeder, and its diet consists of aquatic plants, insects, and small fish. The tufted duck is an important species in the aquatic ecosystem, as it helps to control the populations of aquatic plants and insects.