The Effects of Land-use and Landscape Structure on Barn Owl (Tyto alba) Breeding Success in Southern England, U.K.

Abstract

To aid effective conservation and management there is a need to understand the effect of landscape on species ecology. The aim of this research was to assess the effect of landscape parameters on breeding success of barn owls throughout the Rother and Arun River catchments, Sussex, UK. We used a Geographic Information System to describe the habitat mosaic and landscape structure within an estimated home range area of 3 km2 around 85 artificial nest box sites. Results showed that land cover was less heterogeneous at successful sites, with home ranges dominated by a few habitat types of regular patch shapes. Unsuccessful nesting sites had significantly more improved grassland, suburban land and wetlands than successful sites. Cluster analysis and Principle Components Analysis was used to assess the similarity of the habitat mosaic within these areas and pellet analysis was undertaken to assess barn owl diet and prey availability. Ten prey species were recovered from pellets, field vole (Microtus agrestis), common shrews (Sorex araneus) and house mice (Mus musculus) making up nearly 90% of recoveries. However box sites varied in relative proportions of small mammal, and hence prey availability. Results indicated that land use and landscape structure can affect breeding success in barn owls. Higher levels of poor quality small mammal habitat were associated with unsuccessful sites. However, at a landscape scale, the habitat mosaic across the study area lacked variation, limiting analysis and clear correlations between habitat type and positive breeding success, suggesting that a finer scale was needed in future studies utilising this approach.