A comparative study of breeding bird populations and associated landscape character, Toruń, Poland

Abstract

Comparative studies of bird communities inhabiting urban (three sites — two squares and a cemetery), suburban (one site) and forest (two sites) areas were conducted in Toruń, central Poland. Twenty-eight breeding species were recorded in the urban sites (mean 22.7), 37 species in the suburban forest and 45 species in the surrounding forest (mean 35). The total densities of birds in the town were twice as low as those in the forest. The density of shrub-nesters varied from 1.8 pairs per 10 ha in the town to 65.5 pairs per 10 ha in the forest. The density of insectivorous birds decreased with increasing urbanization from 173.4 pairs per 10 ha in the forest to 22.2 pairs per 10 ha in the town. High densities of omnivorous birds were recorded in the town, 38.2 pairs per 10 ha compared with 0.6 pairs per 10 ha in the forest. While 61.1–78.4% of birds inhabiting the urban sites foraged outside their breeding sites, only 39.4–13.8% of the community did so in the suburban and forest areas. Turdus philomelos, Turdus merula, Phylloscopus collybita and Sylvia atricapilla showed signs of adaptation to green areas in the urban zone and bred in high densities in the suburban forest. The study showed that in urban land management the suburban forests should be saved and protected since they create ecological corridors which enable the birds to colonize the urban habitats and maintain their populations there.