© Marcel Burkhardt
Zehtindjiev, P. & F. Liechti (2003)
A quatitative estimate of the spatial and temporal distribution of nocturnal bird migration in south-eastern Europe - a coordinated moon-watch study.
Avian Science 3: 37–45
In SE Europe, the spatial and temporal distribution of nocturnal migration is
hardly known. With the moon-watching technique the passage of 5603 nocturnal
migrants was recorded during 419 observation hours at 28 sites spread over
Bulgaria, SE Romania and northern Greece. Mean migratory traffic rate was 1400
birds.km-1.h-1 in autumn and 900 birds.km-1.h-1 in spring. Migration intensity
was similar along both E-W and N-S gradients. Flight directions were virtually
opposite between seasons, with a slight shift from SSW to S during the autumn
and from NNE to N during the spring. These results indicate that a high
proportion of nocturnal migrants along the eastern flyway do not circumvent the
eastern Mediterranean Sea, but cross the sea on a broad front. This is in
contrast to the migration along the western fly-way, where a majority of mainly
long distance migrants take south-westerly directions towards the Iberian
Peninsula and thus avoid a long sea crossing.
Keywords: Nocturnal migration, moon-watching, migratory intensity, flight direction, SE-Europe.