Relationships between breeding Barn owls Tyto alba, their prey and agri-environment scheme habitats in lowland arable landscapes.

Abstract

Capsule: Small mammal abundance was greatest in landscapes with a high coverage of grassy field margins, which was also associated with increased fledging success of Barn Owls. Aims: To determine the potential value of agri-environment scheme (AES) habitats for small mammals and, in turn, predatory Barn Owls. Methods: Monitoring of small mammals was conducted across 14 1-km2 British National Grid squares. Survey squares were selected according to a known distribution of Barn Owls derived from monitoring during 2018–2020. We analysed relationships between small mammal activity and coverage of grass-dominated field margins, floristic margins, hedgerows, and tree lines. Barn Owl nest box occupancy in 2021 was analysed in relation to prey abundance (small mammal activity) and the described habitat types. Barn Owl fledging success was then modelled in relation to the prey abundance and the coverage of different habitat types. Results: Our findings suggest that grass field margin habitats are among the AES options most likely to be of value to Barn Owls, as positive relationships with fledging success and prey species were identified. This research is important in providing evidence to support continued implementation and valuing of grass margins under future versions of AES. Conclusion: The study findings suggest that breeding Barn Owls benefit from the provision of grassy field margin habitat, more so than those sown with wildflowers. Our findings add to the body of evidence demonstrating the positive relationships between AES and wildlife and support continued implementation of grass margins on arable farmland.