Finck Peter
Lehrstuhl für Physiologische Ökologie, Zoologisches Institut der Universität Köln, Weyertal 119, D-5000, Köln 41, Federal Republic of Germany.
Oecologia. 1990 May;83(1):68-75. doi: 10.1007/BF00324636.
In a population of Little Owls (Athene noctua) at the Lower Rhine (FRG), the factors were studied that influence the size and shape of territories of this non-migrating, all-year territorial owl species. These studies were carried out between September 1984 and June 1987. The birds were individually marked with transmitter packages so that their locomotional movements could be monitored. Using a standard protable stimulus (a dummy with an attached loudspeaker) the territorial boundaries of 19 male Little Owls were surveilled during the different seasons of the year. Male Little Owls defended their territories in all seasons, but distinct seasonal changes of intraspecific aggressiveness and territory size were observed. The seasonal variations of territory size followed a common pattern in all studied Little Owls, in spite of individual differences in the size of the defended areas. The largest territories were defended in March/April during the courtship season [Formula: see text]. In May/June all male Little Owls reduced the size of their territories [Formula: see text]. This corresponds to the breeding and nestling period. The yearly minimum of territory size [Formula: see text] was reached in the summer months July and August when the fledglings were still fed in the parental territory. When the first-year birds started to disperse in autumn (September/October), the size of the defended areas of the adult tenants again increased [Formula: see text]. In winter (November to February), a further increase in territory size was observed for periods of warm weather [Formula: see text]. Male Little Owls, however, were less aggressive during winter than in the following courtship season. On cold winter days with a ground cover of snow territorial aggressiveness ceased. Pastures and meadows offered a continuous food supply almost throughout the year. In some seasons they were overproportionally represented in the territories of Little Owls compared to the general surroundings. In reaction to changing accessibility of food, the hunting ranges within the home ranges were shifted much faster than the boundaries of the defended territories. The significance of various factors contributing to the variability of territory size in Little Owls are discussed (e.g. availability of food, seasonal and individual differences in aggressiveness, experience in the occupied area, population density).
在莱茵河下游（联邦德国）的一个纵纹腹小鸮种群中，对影响这种不迁徙、全年占据领地的鸮类物种领地大小和形状的因素进行了研究。这些研究在1984年9月至1987年6月期间进行。给这些鸟分别佩戴了发射器包裹，以便监测它们的活动。使用一个标准的便携式刺激物（一个带有扬声器的假鸟），在一年的不同季节对19只雄性纵纹腹小鸮的领地边界进行了监测。雄性纵纹腹小鸮在所有季节都会保卫自己的领地，但观察到种内攻击性和领地大小有明显的季节性变化。尽管被保卫区域的大小存在个体差异，但领地大小的季节性变化在所有研究的纵纹腹小鸮中遵循一种常见模式。在求偶季节的3月/4月，保卫的领地最大[公式：见原文]。在5月/6月，所有雄性纵纹腹小鸮都缩小了它们的领地[公式：见原文]。这与繁殖和育雏期相对应。领地大小的年度最小值[公式：见原文]在7月和8月的夏季达到，此时幼鸟仍在亲鸟领地内进食。当一岁的幼鸟在秋季（9月/10月）开始扩散时，成年领地所有者保卫区域的大小再次增加[公式：见原文]。在冬季（11月至2月），在温暖天气期间观察到领地大小进一步增加[公式：见原文]。然而，雄性纵纹腹小鸮在冬季的攻击性比随后的求偶季节要弱。在有积雪覆盖的寒冷冬日，领地攻击性停止。牧场和草地几乎全年都提供持续的食物供应。在某些季节，与一般环境相比，它们在纵纹腹小鸮的领地中所占比例过高。为了应对食物可获取性的变化，家域内的狩猎范围比被保卫领地的边界变化得快得多。讨论了导致纵纹腹小鸮领地大小变化的各种因素的重要性（例如食物的可获取性、攻击性的季节性和个体差异、在占据区域的经验、种群密度）。
