Methods The food pellets of the wintering Asio otus were collected from urban parks and suburb area of Beijing from 2003 to 2006.

• 方法于2003-2006年冬季应用直接观察法,在北京市城区和城郊结合部收集冬季长耳鸮的食团,分析内容物中鼠类的种类和数量构成。