SEEN - SE European Bird Migration Network
Seasonal migration pattern of owls at Bukowo-Kopań station 2000-2003
Damiana Michalonek
Bird Migration Research Station, University of Gdansk, Poland

Owl migration is rather poorly studied. Studies are quite complicated because of bird nocturnal activity, low number of caught and ringed individuals and small number of recoveries as a result.
We used data collected at the Operation Baltic stations these are nearly 2000 ringed owls caught at Bukowo-Kopań station in autumns 2000-2003. Birds were caught with special raptor nets. They were ringed and measured according to the Operation Baltic standards. 
The Long-eared Owl migration have wave-like pattern with few nights of very high owl number after nights with a very low passage intensity. In some years there are more migrants than in others. This is a result of fluctuations associated with small mammal population dynamics.
It is possible to distinguish two groups of owl species according to passage peaks. Both the Short-eared Owl and the Barn Owl are most numerous at the same time as the Long-eared Owl i.e. at the beginning of November. Correlation is statistically significant every year though not very high. Migration pattern of the Tengmalm's Owl is conspicuously different. Passage maximum of this species occurs on the beginning of October and by the October 25th passage is almost finished. But even then individuals that migrate later are caught at the same time as the Long-eared Owl numerical force occurs.
Obtained results point out that the passage of different owl species is similar to the most numerous and typical migrant species – the Long-eared Owl. This suggests that some common factors influence owl migration must exist.
Created by Pronetix 2006