干旱区生态环境知识资源中心

The Japanese scops owl (Otus semitorques) and Ural owl (Strix uralensis), found in the forests of northeastern China, differ in body size and foraging tactics, and are thus expected to prey on different rodent species. We hypothesized that the Japanese scops owl, an active predator, would prey on smaller and younger individuals than the Ural owl, a sit-and-wait predator. We used pellet analyses to evaluate selection of rodents by the two owls in relation to prey species, age, and size. Although the two owl species consumed a wide range of food items, rodents constituted the most common prey with the greatest biomass in the Japanese scops owl. The Japanese scops owl also foraged on insects and birds, whereas the Ural owl complemented its diet of rodents with spiders, scorpions and snakes. The Japanese scops owl selected smaller and younger rodents and the Ural owl preyed on larger and older individuals. Morphology and behaviour of both prey and predators may explain this differential predation between the two species.