Autumn migratory movements of raptors along the southern Baltic coast

摘要

Some of the known major bottlenecks on European flyways are yet insufficiently explored and require more intensive study. On the basis of raptor counts on the Vistula Spit (southern Baltic coast, Poland), from 15~(th) August to 15~(th) November 2008-2011, we consider this bottleneck to be important at a European scale. Every year we observed there almost 11,000 individuals of 22 raptor species. The flyway is especially important for Peregrine Falcons, Hen Harriers, Merlins and Eurasian Sparrowhawks. To analyse the species composition observed we related the mean annual number of raptors recorded on the Vistula Spit to the corresponding numbers at Falsterbo. The linear mixed model showed that the median migration date showed a significant effect on the species composition and the flight strategies a nearly significant effect. The southern Baltic coast seems to be the most important bottleneck in the autumn passage for late migrating raptors with flapping flight and differ in composition and numbers of species from the flyway at Falsterbo.