This indicates that noise changes top predator assemblage, which in consequence may disturb predator-prey interactions within human-transformed habitats. This study demonstrates that species richness of owls in urban areas may be shaped by landcover heterogeneity and limited by noise intensity. The number of owl species was positively correlated with landcover diversity index and negatively correlated with nocturnal noise emission. In total, 52% of sample plots were occupied by at least one species (1–3 species per plot). Five owl species were recorded in the study area with forests as the dominant landcover type for Tawny and Ural owls, grasslands for Long-eared and Barn owls, and gardens for Little owls. The area of main landcover types, landcover diversity index, mean size of landcover patch, and nocturnal noise level were defined within the sample plots and correlated with owl species richness. Owls were surveyed in the city of Kraków (southern Poland) on 65 randomly selected sample plots (1 km 2). The aim of this study was to identify the role of noise and landcover heterogeneity in the species richness of owl assemblage in the urban ecosystem. However, influence of urbanization on owl communities, anthropogenic noise in particular, has not been investigated so far. Owls are the top predators in most terrestrial habitats, and their presence is a reliable indicator of ecosystem quality and complexity. Habitat loss and fragmentation are listed among the most significant effects of urbanization, which is regarded as an important threat to wildlife.

Are owls nocturnal