| Popis: |
Background: For sedentary birds of prey in the temperate zone, the cold non-breeding season can have strong impacts on fitness traits with implications for population dynamics. The non-breeding season should thus receive the same attention as other parts of the annual life cycle. Birds of prey in intensively managed agricultural areas are repeatedly confronted with unpredictable, rapid changes to their habitat due to farming practices like mowing, harvesting, and ploughing. Such a dynamic landscape is likely to influence prey distribution and availability and might even result in changes in habitat selection of the predator over the annual cycle. Methods: In the present study, we 1) quantified barn owl prey availability in different habitats throughout the annual cycle, 2) quantified the size and location of barn owl breeding and non-breeding home ranges using GPS-data, 3) assessed habitat selection in relation to prey availability during the non-breeding period, and 4) discussed the changes in habitat selection between the breeding and non-breeding period.Results: The patchier prey distribution during the non-breeding period compared to the breeding period led to habitat selection towards grassland during the non-breeding period. Barn owl breeding and non-breeding home-range size were similar, but there was a small shift in the location of home-ranges which was more pronounced in females than males. The changes in prey availability led to a mainly grassland-oriented habitat selection during the non-breeding period. Further, our results showed the importance of biodiversity promotion areas and undisturbed field margins within the intensively managed agricultural landscape. Conclusions: We showed that differences in prey availability among habitat types between the breeding and the non-breeding period can lead to changes in habitat preference. Given these results we demonstrate the importance to maintain and enhance the structural diversity within the intensive agricultural landscape, to effectively conserve birds of prey specialised on small mammals. |
