长尾林鸮（Strix uralensis）是鸮形目（Strigiformes）鸱鸮科（Strigidae）林鸮属（Strix）的中大型猛禽，具有逆性二型（Reversed Size Dimorphism）现象，即雌鸟体重通常大于雄鸟；且繁殖期间长尾林鸮双亲在抚育后代方面有不同的分工：雌鸟主要负责孵卵、育雏和巢防御，雄鸟则主要负责捕食和领域防御。其中，巢防御和领域防御都属于领域行为，作为生殖投资的一部分，均具有风险或消耗能量，因而受到生活史策略的影响。如果个体之间存在生活史权衡策略的差异，那么个体的防御攻击水平也会不同。2018-2019年繁殖季，我在吉林省吉林市永吉县大岗子林场（N43°32′-43°40′，E126°03′-126°14′）对长尾林鸮的巢防御和领域防御行为进行了实验研究。巢防御攻击性以人作为入侵者接近巢树进行测试，领域防御攻击性则以鸣声回放模拟同种个体入侵进行测试。本论文的主要研究结果如下：（1）长尾林鸮巢防御任务主要由雌鸟承担。将20只长尾林鸮雌鸟的62次巢防御行为的攻击等级分0-5级，其中以3级最多，1级和2级次之，0级、4级和5级最少。雌鸟的巢防御攻击性有显著的个体间差异和个体内重复性（R = 0.66 ± 0.11，N = 20，P < 0.001）；雌鸟在育雏后期的平均攻击性与出飞子代数量呈显著正相关（r = 0.58，N=18，P = 0.010）；雌鸟在育雏后期的平均巢防御攻击性与领域内鼠类密度无显著相关（r = 0.26，N = 11，P = 0.43）；当进入异步出飞期，即巢内最大的雏鸟出飞后，雌鸟对巢内其余雏鸟的防御水平均显著低于育雏后期（t = 1.92，df = 9，N = 10，P = 0.040）。（2）繁殖期间，长尾林鸮领域防御任务主要由雄鸟承担；雄鸟的领域防御攻击性也有显著的个体间差异和个体内重复性（R = 0.31 ± 0.15，N = 17，P = 0.020）；雄鸟的领域防御水平与当年领域内鼠类密度无显著相关（r = -0.22，P = 0.40）；个体的领域防御水平与出飞子代数量呈显著负相关（r = -0.48，N = 17，P = 0.040）。（3）雄鸟领域防御水平和雌鸟巢防御水平并无显著相关（r = -0.11，N = 11，P = 0.74），即未发现选型配对的证据。本论文首次报道了中国东北地区长尾林鸮种群的巢防御和领域防御行为模式及个体差异，并对攻击性个体差异的原因和影响展开了探讨，可增进对长尾林鸮这一国家二级保护物种的了解，从而为该物种的保护与复壮提供基础资料。

The Ural Owl (Strix uralensis) is a large owl with reversed sexual size dimorphism with females being larger than males. During breeding, females incubate the eggs and defend the nest, while males feed the female and offspring and defend the territory. Nest and territory defense are part of territorial behavior that related to reproductive investment. As territorial behavior is risky and energy-consuming, if the trade-offs in resolution of life history differs among individuals, the level of defense would vary among individuals. From march to June during 2018 and 2019, we observed the territorial behavior of the Ural Owl in Dagangzi forest (N43°32′-43°40′, E126°03′-126°14′), in N.E. China. In this study, we reported the patterns and variation of the territorial behavior of Ural Owl. Human intruder and conspecific intruder (simulated by song playback) were applied to test the nest defense aggression and territorial aggression, respectively. The main results of this study are as follows: 1) The nest defense of females could be divided into level 0-5, with a significant individual repeatability (R = 0.66 ± 0.11, N = 20, P < 0.0010), as well as positively correlated with the number of fledglings (r = 0.58, N = 18, P = 0.010). Females invest less effort in defense the chicks on the nest after eldest nestling was fledged out (t = 1.92, df = 9, N = 10, P = 0.040). 2) The territorial aggression of males is significantly repeatable (R = 0.31 ± 0.15, N = 17, P = 0.020) and negatively correlated to the number of offspring (r = -0.48, N = 19, P = 0.040). 3) There was no significant correlation between the level of male territorial defense and the level of female nest defense (r = -0.11, N = 11, P = 0.74), suggesting these two factors may not affect mate choice in Ural Owls.