Spatial patterns of seasonal distribution of Corvidae (the case of urban habitats)

Abstract

Corvids in Zhytomyr city reach maximum density in the winter period. Rooks and Eurasian Jackdaws were the most abundant species in winter, usually feeding in multispecies flocks and forming collective roosts.Suburban green areas (buffer zones) were characterized by a considerably high diversity of Corvidae species: this habitat was occupied by all six species. We also registered the highest density of Eurasian Jays and Hooded Crows in this habitat. The green areas in the city center were also characterized by significant corvid density, especially during the breeding season. The maximum breeding density of Rooks was in these habitats, which held 6 of 12 identified urban colonies in Zhytomyr. We found that the European Magpies, Eurasian Jays, and Hooded Crows also had high breeding success here. Eurasian Jackdaws occurred here only in autumn and winter, when they fed together with Rooks on lawns, gardens, and parks. With stable snow cover the Rook density in habitats of the green areas decreased due to the depletion of food resources.The individual buildings zone of the city were characterized by the lowest density of all corvid species, except for European Magpies and Eurasian Jays. The number of common species (Rooks, Eurasian Jackdaws, and Hooded Crows) was low because of shortage of food resources, lack of sites for large roosting flocks and shortage of suitable nesting sites. However, Eurasian Magpies reached one of their highest densities in this habitat (12.8 birds/km2). This species was registered in habitats around private buildings all the year round, successfully nesting in the yards of private houses and on trees in the streets. Its breeding density was 11.2 birds/km2.During three years of research (2009–2012) the density of all corvids except for European Magpie, practically did not change, although we determined a slight positive trend for all the species. The strong increase in the number of Eurasian Jackdaws could be explained by the increasing density of wintering populations or due to the increasing number of migrants from more northern regions.

Why do zoos attract crows? A comparative study from Europe and Asia

“…Our findings may have implications for the planning of urban areas and green infrastructure, as well as potential management implications for zoos regarding free‐living corvids, which may be especially relevant if crows become high in number. In many urban areas of the world, free‐living corvids come into conflict with humans (e.g., Soh, Sodhi, Seoh, & Brook, ), as large concentrations or high nesting densities of corvids may impact the soil and vegetation, decrease urban bird diversity, and present sanitary risks from the crows' use of waste dumps and leftovers for feeding (Matsyura, Zimaroyeva, & Jankowski, ; Zeller & Schuffenecker, ). The high importance of food, especially of anthropogenic food, in the attraction of crows to zoos suggests that appropriate management of such food sources could reduce the attractiveness of zoos to crows, if deemed necessary.…”

Corvids in Urban Environments: A Systematic Global Literature Review

“…Overall, studies conducted over an urban-rural gradient (an order of settings based on the prevalence of human-mad infrastructures in association with human population density) or different urban habitats types, as well as comparative studies between urban and non-urban habitats, were included, since such studies can offer a wider perspective on urbanization’s impact on wild fauna and help to explore disturbance in urban environments [ 15 , 33 , 34 , 35 ].…”

“…Corvidae is a family of mid to large-sized passerines. Many corvid species thrive in many types of urban environments, from the peripheral urban areas to highly urbanized urban core areas [ 13 , 14 , 15 ]. Because of the wide distribution areas of many corvid species and good adaptability to many habitats, corvid species are often described as urban adaptors and even exploiters [ 16 , 17 , 18 ].…”

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

“…With their opportunistic way of life and plastic behavior, corvids are an excellent model group to study the impacts of urbanization on animals. Many corvid species thrive in many types of urban environments, from the peripheral urban areas to highly urbanized urban core areas [ 18 , 19 , 20 , 21 ]. Because of their wide distribution and good adaptability to many habitats, corvids are often described as urban exploiters or adaptors [ 13 , 22 , 23 , 24 ].…”

“…In some areas, such as in the United Kingdom [ 47 ] and Poland [ 48 , 49 , 50 , 51 , 52 ], special attention has been paid to the population trends of both rural and urban corvids. Currently, most of the earlier urban bird studies were conducted during the breeding season, whereas as fewer studies have examined urban birds during the winter [ 19 , 40 , 43 , 48 , 49 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ]. However, because of the scarcity of resources and the severity of weather conditions in northern latitudes, winter is the most critical season for many birds [ 65 , 66 ].…”