White-Headed Duck

(Oxyura leucocephala), a bird of the family Anatidae. The white-headed duck is approximately 55 cm long and weighs as much as 900 g. The plumage is brownish gray with dark speckling. The male has a blue bill and a white head with a black crown, and the female has a brown head with a gray bill. The white-headed duck is distributed sporadically in arid steppes and deserts from Spain and Morocco to the Tuva ASSR. The duck nests most often on brackish lakes on a mass of floating vegetation, often occupying the old nests of coots and other birds. A clutch contains six large eggs. It appears that the female broods the eggs only during the first half of the incubation period, and the embryos develop further without heating. The white-headed duck feeds on aquatic plants and small invertebrates. It has practically no commercial significance.