Diet of Long-eared Owl and Common Kestrel in an urban landscape (Ukraine)

Ivan Komarnytskyi,Oleksii Dubovyk,Ihor Dykyy,Ivan Zahorodnyi

doi:10.2478/orhu-2021-0008

Abstract

Abstract In the present study we performed a comparative dietary analysis of two predatory birds, the Long-eared Owl (Asio otus) and the Common Kestrel (Falco tinnunculus) in the district of Lviv city. We found that the Long-eared Owl and the Common Kestrel are typical small mammal specialists within the urban ecosystem. Considering the abundance and biomass of prey, small mammals comprise 98.4% of the Long-eared Owl’s diet. The species composition of mammals coincides almost 50% in the food intake comparison of the two birds. It has been established that the main prey of both species is the Common Vole (Microtus arvalis). The diet of the Common Kestrel is more varied, compared to the Long-eared Owl, due to the consumption of different species of insects (families Gryllotalpidae, Tettigoniidae, Carabidae and Scarabaeidae), reptiles and birds. This result suggested that dietary plasticity of the Common Kestrel facilitate successful adaptation to the urban landscape. The Long-eared Owl is more narrowly specialized in feeding on murine rodents, which reduces the trophic competition between the two predatory birds and allows the coexistence of two predators in the urban ecosystem.

Highlights

The contemporary state of the world’s fauna can be described by unprecedented scales of its changes, which are mainly caused by an anthropogenic factor (Zagorodniuk 2006)
Birds are exposed to significant ecological disturbance. It mainly concerns the natural populations of predatory birds, as one of the most vulnerable taxa that are forced to change their behavior and spatial distribution, which is mainly reflected in their foraging – a primary physiological demand of the living organism
Small mammals comprise 98.4% of the diet of the Long-eared Owls in number and biomass. 13 species of small mammals were identified in total

Summary

Introduction

The contemporary state of the world’s fauna can be described by unprecedented scales of its changes, which are mainly caused by an anthropogenic factor (Zagorodniuk 2006). We were able to observe intensified development of disturbed human environments. This significantly changed natural habitats (Dziemian et al 2012), but it could create new ecological niches for many species (Luniak 2004, Żmihorski & Rejt 2007). The topic of changes in fauna is being actively discussed and is developing in academia. This topic is commonly ignored in Ukraine, so that the lack of information exists in this field (Zagorodniuk 2006)

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Discussion

Conclusion