We studied nest sites and nest tree characteristics of Long-eared Owls (Asio otus) in Zuojia Nature Reserve of Jilin Province,China.Our study sites,42km 2,were distributed in middle of Jilin Province (126°0′~126°1′N,44°6′~45°2′E),which was located on hill extending from eastern Changbai Mountain to western plain,ranging from 200m to 500m above sea level.The climate was east monsoon climate,characterized hot,dry summers and cold,snowy winters.The two dominant vegetation types present on the study area were ...