Why do zoos attract crows? A comparative study from Europe and Asia. Issue 24 (26th November 2019)

• Record Type: Journal Article
• Authors: Kövér, László; Lengyel, Szabolcs; Takenaka, Makiko; Kirchmeir, Alice; Uhl, Florian; Miller, Rachael; Schwab, Christine
• Is Part Of: Ecology and evolution. Volume 9:Issue 24(2020)
• Page Start: 14465
• Page End: 14475
• Publication Date: 2019-11-26
• Subjects: adaptation -- artificial food -- city planning -- Corvidae -- pest management -- urban ecology; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.5881
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Crows have successfully colonized many cities, and urban zoos have been important in this process. To evaluate why zoos attract crows, we quantified crow numbers and behavior in three zoos in Europe (Debrecen, Edinburgh, Vienna) and one in Asia (Sapporo). Data were collected in 445 surveys over 297 days in summer 2014 and winter 2014–2015. We found that crow numbers were highest in Vienna, intermediate in Debrecen and Edinburgh and lowest in Sapporo, increased significantly from summer to winter (Debrecen, Edinburgh, Vienna), and from mornings to afternoons (Debrecen, Sapporo, Vienna), and were higher in sunny weather than in cloudy weather with precipitation and when visitor numbers were low (Debrecen, Vienna). The crows' use of natural food was highest in Vienna, intermediate in Edinburgh and Sapporo, and low in Debrecen. The use of anthropogenic food was high in Debrecen and Sapporo, where the availability of open grassy areas typically used by crows for natural foraging was low. In Sapporo, food availability was more limited than in other zoos, resulting in strong territoriality and few crows in summer, which decreased further in winter. Our study indicates that crows are primarily attracted to zoos by food availability and secondarily by breeding opportunities and that the relative importance of natural versus anthropogenic food sources may vary with zoo habitat structure. Our study draws attention to a previously overlooked role of zoos in urban biodiversity conservation. It may also provide useful information for the management of crow populations, if necessary, and for the planning of urban areas. Abstract : Crows are primary attracted to zoos by food availability and secondly by breeding opportunities. Crows' number increased significantly from summer to winter and from mornings to afternoons. The number of visitors influenced crow numbers as well as the availability of food. The structure of zoos and food management affected the appearance of crows. Zoos could play important role regarding to crow control.