Abstract
A lot of studies exist on the soaring bird migration along the Eastern Mediterranean migration route. However, most of them are focused on the avian species composition and numbers, while the migration patterns and the influence of weather conditions are still poorly investigated. The present study is focused on the migration of White Storks in northeastern Bulgaria, based on data collected for 6-year period (2004- 2010) from 33 observation points. Our aim was to investigate the horizontal and vertical distribution of migrating storks, and how the dynamics of these distributions was influenced by the weather conditions. We demonstrated that the migration route of White Storks in the study area extends up to 70 km inland from the coast. The most intensive was the migration in the early afternoon, during the last 10 days of August and under north-coming winds. The majority of storks was flying above 400 m and the altitude of flight was influenced by the air temperatures and the day hour. The main driver for the flight distance from the sea was the wind direction. Considering the potential negative cumulative effects due to the high concentration of wind parks in northeastern Bulgaria, we emphasise that the prospective intentions for construction of wind farms, even located at 70 km from the coast, should be subjected to careful studies on the soaring bird migration through the area.