Abstract The following study contains data from 2420 preys found in Barn Owl pellets from 16 sites of the Salento peninsula (Apulia, Italy). Nine preyed species were detected. Microtus savii was the most frequent prey. No specimen of Clethrionomys glareolus, Muscardinus avellanarius and Sorex spp. were ever found, probably for ecological and bioclimatological reasons. The relatively low values of some ecological parameters (Richness, Trophic level, Diversity) suggest that the micromammalian populations in Salento are influenced, locally, by both anthropic and biogeographical factors. These results may be inserted into the general debate on the "peninsula effects".