Il ruolo dei micromammiferi nella dieta invernale del gufo comune nella Pianura Padana Cremonese

Small mammals are useful bioindicators to assess ecosystem health. Little is known about populations of small mammals in Southern Lombardy (Northern Italy, Cremona province). Although anthropogenic pressure in this area is very high, due to the high concentration of industries and intensive agriculture, several habitats of European concern also occurs. Pellets of long-eared owls Asio otus collected in this area in winter months confirm that this species has a generalist diet, mostly composed by small rodents. In particular, synanthropic species such as rats Rattus spp. and the house mouse Mus domesticus represent, together with the Savi's pine vole Microtus savii, the staple of the diet of this nocturnal raptor. On the contrary, in recent years, the presence of the harvest mouse Micromys minutus has not been detected in the diet of the long-eared owls, despite being reported in studies of the early 2000s. The use of pellets to assess the trend of small mammalian populations has been proven to be very cost-effective. Biases can be corrected using direct captures, despite requiring a high field effort and sampling time. The ongoing climate change is favoring thermo-xerophilic species over mesophilic ones. We therefore recommend to conduct owl diet analyses continuously, in the long term, to have constantly up-to-date data and to improve management measures to preserve habitats and communities.