INFLUENCE OF SNOW COVER ON PREY SELECTION BY LONG-EARED OWLS ASIO-OTUS

During winter the composition of the diet of the Long-eared Owls present at a roost varied in relation to the ground snow cover; birds and riparial rodents increased when ground cover was complete. A comparison between diet and prey availability (assessed by trapping) showed that small mammal species were mostly preyed upon in relation to their abundance; the scarce presence of Insectivores in the diet is apparently due to their reduced seasonal availability. Long-eared Owls behaved as adaptable predators; their dietary specialization in Northern Europe may be due to the great abundance of Microtinae at high latitude.