Abstract
Between August 27th and September 30th 2014 the intensity of nocturnal bird migration was measured in the Dobrudzha Region (NE Bulgaria) using a specific bird radar. During the same time period and in the same area (part of Natura 2000 net BGSPA0002051 Kaliakra and adjacent areas), road-kills as well as collisions of birds with wind turbines were recorded. Along a 9-km-long secondary road, 95 dead birds out of 24 species belonging to six orders were found. A systematic carcass search under 52 wind turbines was examined and eight collision victims belonging to five bird species of four orders were discovered. The results did not show a relation between bird mortality due to wind turbine collisions and nocturnal migration. However, a positive correlation between night passerine migration intensity and road mortality of passerines was found. Windfarms do not appear to be more detrimental to migrating birds than other anthropogenic sources of mortality, such as automobile traffic. The recorded high number of road-kills in the designated Natura 2000 zone Kaliakra provides a basis for planning additional restrictions in this zone, in order to secure the habitats, which are important for migrating passerine birds.