Patterns of Bird Migration Defined by a Weather Radar at Part of the East European Flyway (Via Pontica)

The results of the first comprehensive radar survey of the spring and autumn bird migration in Bulgaria in a key area of the migratory flyway Via Pontica are presented. The weather radar of Bulgarian Air Traffic Ser- vices Authority (BULATSA) located nearby the town of Aksakovo (Varna Region, North-Eastern Bulgaria) was used. The survey covered 1101 days and nights of four years (2014–2017). It wa…