The effects of land use changes on site occupancy and breeding success of the barn owl (Tyto alba) from 1993 to 2020

Land use changes, driven by human activities such as agricultural intensification and urban expansion, have drastic effects on biodiversity. As these changes are anticipated to continue, understanding species’ adaptations to their evolving habitats is essential to find solutions for effective conservation efforts and sustainable management. In this study, we investigated how long-term changes in the agricultural landscape influence the breeding performance of a population of barn owls (Tyto alba) residing in nest boxes using data collected from 1993 until 2020. Specifically, we assessed how agricultural intensification, urbanization, and site availability affected barn owls’ site occupancy and breeding success. Our results reveal that nest boxes surrounded by more agricultural fields are more likely to be occupied and have higher fledging success. Additionally, nest boxes installed higher on the barn were more likely to be occupied. Owls laid more eggs in nest boxes facing North than South or East. Clutches laid in nest boxes installed at higher altitudes were smaller. Finally, nest boxes with a higher density of surrounding nest boxes were less likely to be occupied and had smaller clutches. These insights show barn owls high reliance on the agricultural landscape surrounding their nesting sites, but also the importance of nest box characteristics to optimize their breeding success.

Keywords: Agricultural intensification, Urban expansion, Land use change, Barn owl fitness