Canadian Journal of Zoology (2010) 88, 416-426

Nadine Bernard, Dominique Michelat, Francis Raoul, Jean-Pierre Quéré, Pierre Delattre and Patrick Giraudoux (2010)
Dietary response of Barn Owls (Tyto alba) to large variations in populations of common voles (Microtus arvalis) and European water voles (Arvicola terrestris)
Canadian Journal of Zoology 88 (4), 416-426
Abstract: 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, 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.
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Link to article at publishers website
Database assignments for author(s): Patrick Giraudoux

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Arvicola terrestris		France
	Microtus arvalis		France
Tyto alba (predator)	Arvicola terrestris		France