Dietary response of barn owls (Tyto alba) to large variations in Microtus arvalis and Arvicola terrestris prey populations

• Published in: Canadian Journal of Zoology
• Main Authors: Bernard, Nadine, Michelat, Dominique, Raoul, Francis, Quéré, Jean-Pierre, Delattre, Pierre, Giraudoux, Patrick
• Other Authors: Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté COMUE (UBFC)-Université Bourgogne Franche-Comté COMUE (UBFC), Centre de Biologie pour la Gestion des Populations (UMR CBGP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD France-Sud )-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: small mammals; prey population densities; diet; Barn Owl; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Jura; Microtus arvalis
• Online Access: https://hal.science/hal-00451728; https://doi.org/10.1139/Z10-011

E-mail Addresses: [e-mail] International audience The diet of the Barn Owl (Tyto alba (Scopoli, 1769)) was studied over an 8-year period in the Jura mountains of France, during two population surges of its main rodent prey (common voles (Microtus arvalis (Pallas, 1778)) and European water voles (Arvicola terrestris (L.,1758))), allowing us to test whether T. alba is an opportunistic predator as is often cited in the literature or exhibits more complex patterns of prey selection as is reported in arid environments. Small mammals were sampled by trapping and index methods. We observed (i) significant correlations between the proportions of A. terrestris and M. arvalis and woodland rodents in the diet and their respective densities in the field; (ii) interactions between populations of A. terrestris and M. arvalis, indicating that the proportion of each species in diet was affected by the density of the other; (iii) proportions of red-toothed shrews (genus Sorex (L., 1758)) in the diet did not correlate with their abundance in the field, indicating that those species were likely to be preyed upon when others were no longer available. This confirms that T. alba is generally opportunistic; however, prey selection of a focal species (e.g., Sorex spp., grassland species) can be affected by the density or availability of the other prey species