Common Buzzard (Buteo buteo) population during winter season in North-Eastern Romania: the influences of density, habitat selection, and weather

Common Buzzards (Buteo buteo) in Eastern Europe are partial migrants, and their numbers in a specific area fluctuate during the winter season. In the cold season of 2010-2011 we carried out 15 car-transect counts, each 40 km in length, during four months (November-February) to study the wintering population of the Common Buzzard in North-Eastern Romania. The counts revealed a density of 0.334-0.539 individuals/ km for the winter season. Birds were non-randomly distributed across habitat types: agricultural land and especially areas with natural perches (trees or bushes) were used disproportionately commonly. The density of Common Buzzard varied during the four months, and was influenced by temperature. The numbers of Common Buzzards peaked at transects with complete snow cover and during periods of lower-than-average temperature.