The eco‐geographical Bergmann's rule predicts that animals have smaller body size in warmer regions than in cold environments because of thermoregulatory reasons. Although this rule has been widely investigated, intraspecific analyses on cosmopolitan taxa are rare. We examined whether geographical variation in wing length, a proxy of body size, shows a Bergmannian pattern and can be explained by three mechanisms known to affect animal body size (heat conservation, resource availability and starvation resistance) in seven species of nocturnal raptors of the genus Tyto.

中文翻译：

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伯格曼法则的通用证据：大都会猫头鹰属的体型变化

生态地理学的伯格曼法则预测，由于温度调节的原因，与较冷的环境相比，较温暖的区域动物的体型较小。尽管已经对该规则进行了广泛研究，但很少有人对大都会类群进行种内分析。我们检查了机翼长度的体长的地理变异（是否代表体长）是否显示了贝尔格曼模式，并且可以通过已知的三种机制来解释这七个物种的夜间猛禽的影响动物体长的三种机制（热守恒，资源可利用性和抗饥饿性）。Tyto属。