Opportunistic citizen science data reveals habitat selection of lesser black-backed gulls in Central Europe

This study is the first attempt to find a relation between the opportunistic observation data of an easily identifiable but locally rare bird, in our case the lesser black-backed gull (Larus fuscus fuscus), and the Corine Land Cover habitat map by applying a resource selection function model to reveal the habitat selection of the species. We provide a scientific analysis using the valuable citizen science dataset sourced from the www.birding.hu website, collected by hundreds of volunteers over a span of more than a decade in Hungary. Birds selected for landfills, river and lake habitats and showed a significant but much smaller attraction towards urban areas, while they selected against arable lands. We found that in the case of rare and moderately common birds, we can obtain a representative picture of the habitat selection of the species, even if the data are collected by non-standardized means.