A Core On The Edge: An Urban Bird Assemblage On The Atlantic Margin Of Europe

Abstract

Urbanization threatens bird populations globally, however many urban habitats present important refugia for wildlife in this rapidly changing landscape. Additionally, birds at the periphery of their global range are more prone to landscape changes and thus these distributions are good indicators of the effects of urbanization on diversity; e.g., bird populations and communities of Cork City, Ireland. The aim of this study was to evaluate effects from urbanization on bird densities (birds/ha), species richness, and species composition throughout Cork City. I surveyed 32 points selected with a stratified random sample within commercial areas, residential habitats, and green spaces throughout Cork City during four breeding seasons between 2016–2019. Species richness was highest in green spaces with 18–34 species; whereas residential habitats had 14–27 species and commercial areas had 9–20 species. The most densely populated species citywide were Rock Pigeons (5.4–9.1 birds/ha), Eurasian Jackdaws (2.9–3.8 birds/ha), Rooks (4.5–6.4 birds/ha), European Starlings (3.4–5.3 birds/ha), Eurasian Blackbirds (2.4–3.6 birds/ha), and House Sparrows (2.7–4.5 birds/ha). Overall a lack in urban green space surrounding survey points was most strongly associated with reduced species richness and population estimates. Also, both species richness and population densities tended to be higher in regions with less noise pollution and farther from the urban core. Ultimately these results corroborate other studies stressing the importance of urban green spaces for conserving biodiversity in cities. This is particularly important for the birds of Cork City given that these urban habitats are at the western edge of these species’ distributions.