Great Cormorant (Phalacrocorax carbo) Science Article 26
This paper describes distribution and population development of the continental race of the Cormorant in its central and eastern European breeding range. After a period of severe human persecution until halfway this century, the populations started to rise from about 1980 onwards, parallel to the rise in the western breeding range. Mean annual growth rates ranged from 14% in Poland to 27% in Sweden. Systematic disturbances of newly established settlements have locally lowered the overall growth rate, but may have been responsible for further eastward expansion of the breeding range. Considering the timing of the population growth and the level of the growth rate, the recent developments of this population do not seem to be caused by the increase of the western population. Contaminant levels, though at least locally high, are unlikely to have had any noticeable negative influence on reproduction and/or population development. The role of eutrophication is suspected to be of importance, but proofs will still have to be found.
Lindell L., Mellin M., Musil P., Przybysz J. & Zimmerman H., ARDEA 83 (1): 81-92.