Distribution and habitat selection of the Black-headed Duck (Heteronetta atricapilla)

Abstract

The Black-headed Duck is found in the temperate or, rarely, subtropical zones of South America, including most of central and northern Argentina, coastal Uruguay, the south coastal tip of Brazil, central Paraguay and central Chile. Only one record is known from eastern Bolivia. Breeding records are known only for Argentina, Chile and Paraguay. Unlike northern hemisphere ducks, there is no clear-cut geographic difference between breeding and non-breeding ranges. Migration is probable, but its extent is uncertain. Although there is not a complete exodus from the breeding areas in Buenos Aires Province, concentrations are common in northwestern Argentina. Additional banding data are needed badly. Throughout their range, Black-headed Ducks are found mainly in semi-permanent, fresh marshes dominated by juncos. Throughout Argentina, Rosy-billed Pochards frequented the same areas.