The Breeding Population Of Rook Corvus Frugilegus In Major Cities Of Podlaskie Voivodship (NE Poland)

Abstract Until now, there was no relevant data about the rook breeding populations in cities of north-eastern Poland. The main research was conducted in 2012, whereas in Białystok, which is the capital of Podlaskie voivodeship, the data was collected also in 2007. During the research 2329 nests forming 42 colonies were noted in three major cities, i. e. Białystok, Suwałki and Łomża. Mean density in mentioned cities was 5.17 pairs/km2, 9.71 pairs/km2 and 33.09 pairs/km2 respectively. In Białystok and Łomża the colonies were located only in the city centre, while in Suwałki they were observed also in the suburbs. Between 2007 and 2012 in Białystok has been a slight increase in the number of colonies and of their average size and, simultaneously, a decrease in the number of pairs nesting separately.