Corridors, local food resources, and climatic conditions affect the utilization of the urban environment by the Black‐headed Gull Larus ridibundus in winter

Abstract

AbstractBlack‐headed Gulls Larus ridibundus (BHGs) in urban areas are a public nuisance. The aim of this study is to investigate the factors affecting the occurrence and abundance of the BHG foraging in urban areas in winter. The study was conducted in the city of Krakow (southern Poland) in four easily identifiable urban habitats: (1) areas with blocks of flats, (2) areas with congested housing, (3) detached single‐family housing and (4) green areas. In each of these four habitats, 60 small (1‐ha) plots were randomly chosen, and the bird's presence and abundance were noted. Results revealed that birds occurred most frequently and in the largest numbers in plots with blocks of flats and green areas as well as plots located close to rivers and water reservoirs. This highlights the importance of ecological corridors and stepping‐stones for the presence of this species in the city. Food resources had no effect on the presence of the gulls but the abundance of the species was positively correlated with the number of litter‐bins. This indicates that local food resources could be more important than large landfills for this species in urban habitats during winter. No human disturbance indices had an effect on the occurrence and abundance of the BHG. Higher temperature and lack of snow cover positively affected utilization of the urban habitats by the species that indicates that global warming may speed up synurbanization of the BHG. To control the number of BHGs in urban areas, we suggest preventing access to local food resources by placing litter bins with waste baskets that are inaccessible to animals. Also, the public should behave appropriately towards gulls and refrain from feeding them intentionally.