We analyzed the pellets of Long-eared Owls Asio otus in Nagano and Iiyama Cities, Nagano Prefecture, central Japan. A total of 370 pellets which were collected at two roosts in Nagano City in five wintering seasons from 1992 to 2002 included the remains of 548 animals. In 1999, on the other hand, we collected 30 pellets at a breeding site in Iiyama City. They were comprised of 36 animals. The collected pellets included five Rodentina, one Chiroptera, one Insectivora and small birds. Rodents represented more than 90 % of the pellet contents, with Microtus montebelli predominant in all sampling sites. Furthermore, a pellet collected in winter contained three or four Pipistrellus abramus which are assumed to be dormant in that period.
