Autumn migratory movements of raptors along the southern Baltic coast

Abstract

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