Description
The area at the Danube reservoir at Greifenstein consists of a roughly 2.5-kilometre peninsula (1) that separates the Danube (2) from an old southern side arm (3). Around 220 species have already been recorded in the area. Most interesting are gulls, ducks, geese, and divers which stay from mid-October until early spring.
The side arm (3) is best explored on foot or by bike from the southern path “Am Damm.” Afterwards, it is worth walking across the “Die Schwelle” bridge to the Danube lock. Along the way you pass several small islets that are also worth checking. From dam on the lock, only the eastern part of the Danube is visible, where gulls and cormorants rest. As early as late summer and autumn, the Mediterranean Gull is occasionally sighted, followed somewhat later by the European Herring Gull. More common are Yellow-legged Gull, Caspian Gull, and Black-headed Gull. The Little Gull has been recorded especially in November. Four sightings of the Great Black-backed Gull and three of the Kittiwake also come from the cold season. Records of the heuglini subspecies of Lesser Black-backed Gull ("Heuglin's gull") and Glaucous Gull are rare but confirm the site’s potential. Among cormorants, the Atlantic subspecies P. c. carbo is regularly observed.
The island (1) is covered with a strip of alluvial and deciduous forest. Noteworthy among the probable breeding birds are Collared Flycatcher, Middle Spotted Woodpecker, and on the islets the Common Sandpiper. Most surveys in the area, however, take place outside the breeding season; in the summer, the side arm is frequented by swimmers and water sports enthusiasts. Of particular interest are the winter gatherings of waterbirds either on the side arm or on the impounded Danube itself (2), which reach their peak in January. They can be viewed from the northern path, which is heavily used by cyclists.
Among the ducks, the Tufted Duck is the most numerous. A regular guest between November and January is the very similar Greater Scaup. Less frequently at the same time, the Velvet Scoter, Slavonian Grebe and Red-necked Grebe are recorded, and even more rarely the Long-tailed Duck. Those not lucky with rarities can expect Goosander, Common Goldeneye, and Lesser Black-backed Gull. The food-rich area also regularly attracts the White-tailed Eagle.
Details
Access
The Danube side arm and reservoir are located in Greifenstein, about 25 km north of Vienna. While parking is possible (click on "P" on the map to get directions), the area is best reached by public transport or bicycle. The paths are wheelchair accessible.


