Nest-site and landscape characteristics affect the distribution of breeding pairs of European Rollers Coracias garullus in an agricultural area of southeastern France

Understanding factors that drive the choice of breeding habitats for birds is important for species management and conservation. We addressed this question in the case of the European Roller Coracias garrulus, an endangered species listed in Annex I of the European Union directive for bird conservation. For secondary hole-nesting birds, such as rollers, the breeding micro- and macrohabitat selection may rely on the location of the nest hole in a tree and its immediate surrounding environment as well as the larger scale foraging habitat. We used both of these criteria to compare the characteristics of Green Woodpecker Picus viridis holes that either were or were not occupied by breeding pairs of the European Roller. Our study was carried out in an agricultural landscape of southeastern France where the population of European Roller is trending towards an increase. When compared to unoccupied holes, occupied holes were at a lower height (approx. 6 m above ground) and were preferentially located in dead trees with other holes in close vicinity. Occupied holes were also located in landscapes with lower land use intensity (i.e., higher proportions of meadows, fallow lands, and fewer hedgerows and built areas) than non-occupied holes. Finally, fallow lands and meadows harboured more Orthoptera, an important food resource for rollers, than other land cover categories. Thus, our results highlight the importance of these land covers for the species management and indicate that they may be favourable areas for nest-box provisioning.