Winter habitat selection of Corvids in an urban ecosystem

Abstract

Urban areas attract birds during the winter when cities provide a predictable source of food and relatively stable weather conditions. However, many other factors determine the occurrence of birds in cities. This study analysed the relationship between corvids wintering in the city of Poznań, in western Poland and habitat features. Each of 32 research site was investigated three times. The most abundant species was the rook (mean = 17.4 individuals/site); the most frequent was the Eurasian magpie (88% of all sites). To determine variables that influence the abundance of birds, a set of generalised linear models was created, with model averaging being selected for each species. The abundance of hooded crows was positively influenced by surface of parks, water and by the length of tram tracks. The number of rooks was positively linked with the number of walnut trees, garbage cans and the surface of the water and negatively linked with the length of watercourses. Jackdaw was affected positively by the number of garbage cans, the surface of the water and negatively by the cover of trees. The number of magpies was associated with the number of walnut trees, garbage cans and negatively influenced by the surface of trees. None of the investigated habitat variables significantly affected the abundance of European jay. We also found a positive correlation between the abundances of hooded crow, rook, jackdaw and magpie. The results indicate that corvids wintering in urban ecosystems exhibit selectivity toward specific habitat features and that preferences differ among the studied species.

Nest-site selection of an avian urban exploiter, the Eurasian magpie Pica pica, across the urban-rural gradient

“…Our study confirms a pattern previously reported in other European cities that the Eurasian magpie successfully exploits the urban environment, especially green urban habitats, including gardens, orchards or avenues of mature trees that represent crucial nesting habitats in an urban environment (Jokimäki et al 2017, Szala et al 2020). An important adaptation of Eurasian magpies to living in an urban environment may be one of adjusted nesting behaviour (Wang et al 2008), as magpies select higher trees to nest on within urban habitats than in rural habitats.…”

Caching territoriality and site preferences by a scatter‐hoarder drive the spatial pattern of seed dispersal and affect seedling emergence

“…We observed that some magpies maintained their territories during the entire year, switching the territorial behaviour from caching seeds to nesting. Magpies usually remain in their nesting territory throughout the year but sometimes they move to other locations and return in spring (Birkhead, 1991; Szala et al., 2020). We showed that nest distribution varied between years, but the dispersal patterns matched the VPs derived from the nest distribution that appeared in the spring after the acorn dispersal season.…”

“…To address this goal, we used the interaction among Eurasian magpie ( Pica pica L.) and holm oak ( Quercus ilex L.) as our study system. Magpies are massive acorn scatter‐hoarders, that is, disperse large number of acorns (Martínez‐Baroja et al., 2019) and territorial breeders (Baeyens, 1981; Birkhead, 1991; Szala et al., 2020) that inhabit open landscapes. The holm oak is the most important tree in agroforestry systems in the western Mediterranean Basin (Pulido & Díaz, 2005).…”

Long-Term Winter Population Trends of Corvids in Relation to Urbanization and Climate at Northern Latitudes

“…Our results indicated that fewer corvid species are urbanized in Finland than in southern and central Europe. For example, we detected the Rook only once even though the species is very abundant in more southern urban areas (e.g., [ 48 , 49 , 79 ]). The Rook became a member of the Finnish avifauna no earlier than the late 1800s, and it is still breeding in only a few sites in Finland [ 80 ].…”