Marcin Przymencki, Klaudia Litwiniak, Szymon Beuch, Jan Rapczyński, Łukasz Wardecki, Łukasz Bednarz, Anna Włodarczak-Komosińska, Przemysław Doboszewski, Łukasz Borek, Maciej Rębiś, Paweł T. Dolata, Piotr Zieliński, Kamil Bilecki, Dariusz Węcławek, Monika Bukacińska, Dariusz Bukaciński
Ornis Polonica 2024, 65: 30–41
https://doi.org/10.12657/ornis.2024.1.2
Abstract: Nesting of gulls on urban infrastructure components has been known for more than 100 years. This phenomenon is commonly explained by the hypothesis that the population growth rate is higher than the availability of nesting sites in traditional habitats. The roofs of buildings, where gulls often nest, provide certain benefits, such as avoiding predation by mammals and a lower probability of disease transmission. However, birds primarily foraging on anthropogenic food may have lower breeding success. The Common Gull Larus canus is considered as vulnerable to extinction in Poland, with a population decline recorded since the second half of the 1990s. It began nesting in Polish cities in this period, but the intensification of inhabiting urbanized areas occurred in the last 10–15 years. In 2023, 227 breeding pairs were nesting on urban infrastructure components. The highest number of pairs was recorded in Włocławek (136), followed by Warsaw (29) and Płock (27). Some nests were also found in cities outside the Vistula river valley, such as Olsztyn, Ostrów Wielkopolski and Stargard. The birds mainly inhabited rooftops, which were the nesting sites for over 90% of the surveyed population. Due to difficulties in finding the Common Gull nests in cities, we believe that the reported population size may be underestimated. Despite certain threats associated with nesting in this habitat, it is anticipated that urban colonization will increase and may lead to population growth, as was observed in other countries.
Keywords: anthropogenic structures, cities, gulls, nesting, rooftops, synurbization
