Die Bedeutung der Donau als Rastplatz Überwinternder Entenvögel (Anatidae)

Abstract

Wintering waterfowl has been counted on the river Danube in Lower Austria since 1964/65. Nearly all species reach their maximal numbers in january, but of the twenty duck species, that have been watched during the whole time, only three are important: Mallard, Goldeneye and Goosander. They show a characteristic pattern of distribution on that part of the Danube where counting has been regularely undertaken. The most Mallards are found downstream of Vienna, Goldeneye and Goosander avoid this part of the river, one finds their maxima on the upper parts of the river. The possible reasons for this fact are discussed, such as the dirty water downstream of the city or the form of the river banks, for example rubble banks or artificial banks with steep slopes, which the ducks generally avoid.