Tawny Owl Strix aluco Distribution in the Urban Landscape: The Effect of Habitat, Noise and Light Pollution

Abstract

At present, the intensification of urban landcover is one of the most critical threats for biodiversity. Common side-effects of urban sprawl are anthropogenic noise and artificial light at night (ALAN). Although their negative effects have often been described, little research has concerned nocturnal wildlife, especially avian predators. Here, we investigated the effect of urban and tree cover, traffic noise and ALAN on the presence of the Tawny Owl Strix aluco, a common night-active predator in Europe. We conducted playback surveys along an urban gradient in Turin (Italy) to detect species presence. Traffic noise was measured in the field, the cover of built-up and (semi-)natural areas was estimated using GIS and multiple measures of ALAN were acquired from a light pollution map. We modelled species presence as a function of each environmental predictor and we found a significant negative relationship with light pollution, which was the foremost urban stressor affecting Tawny Owl occurrence. Our findings suggest that Tawny Owls are more likely to be found in less artificially illuminated areas and that their distribution in urban areas is not only influenced by noise pollution and the availability of suitable habitat, but also the intensity of ALAN. Therefore, light pollution could be a key driver of the spatial distribution of Tawny Owls and potentially other nocturnal species in urban ecosystems.