Breeding density and nest-site selection of urban population of the fieldfare Turdus pilaris in Rzeszow (SE Poland)

Numerous studies have investigated the nest-site characteristics and selection of bird species, because these features often play a determining role in bird breeding success. In recent years researchers focused on urban environments as a source of novel conditions which provide breeding opportunities for species that are able to survive in human-altered environments. Although thrushes Turdus spp. are among the species which frequently inhabit urban areas, the fieldfare Turdus pilaris only recently has started to colonize human settlements and reports on populations in urban ecosystem are rare. The aim of our study was to investigate the fieldfare density and nest-site selection in urban parks of Rzeszow, Poland. We found that the average density of breeding pairs in study area was 2.92 pair/ha. Fieldfares nested entirely on deciduous trees, despite the presence of numerous coniferous trees in parks. They built their nests mostly on those tree species which were the most abundant in particular study plot, which indicates that the studied urban population of the fieldfare is rather opportunistic in the selection of a nest-tree species. Also nest-tree surroundings consisted of the trees that dominated in the parks. The results of our study suggest that the fieldfare is among the species that synurbize easily and may reach even higher breeding densities in towns than in natural habitats.