Dispersal is a key process with crucial implications in spatial distribution, density, and genetic structure of species’ populations. Dispersal strategies can vary according to both individual and environmental features, but putative phenotype-by-environment interactions have rarely been accounted for. Melanin-based color polymorphism is a phenotypic trait associated with specific behavioral and physiological profiles and is, therefore, a good candidate trait to study dispersal tactics in different environments. Here, using a 40 years dataset of a population of color polymorphic tawny owls (Strix aluco), we investigated natal dispersal distance of recruiting gray and pheomelanic reddish-brown (hereafter brown) color morphs in relation to post-fledging winter temperature and individual characteristics. Because morphs are differently sensitive to cold winters, we predicted that morphs’ natal dispersal distances vary according to winter conditions. Winter temperature did not affect the proportion of brown (or gray) among recruits. We found that dispersal distances correlate with winter temperature in an opposite manner in the two morphs. Although the gray morph undertakes larger movements in harsher conditions, likely because it copes better with winter severity, the brown morph disperses shorter distances when winters are harsher. We discuss this morph-specific natal dispersal pattern in the context of competition for territories between morphs and in terms of costs and benefits of these alternative strategies. Our results stress the importance of considering the interaction between phenotype and environment to fully disentangle dispersal movement patterns and provide further evidence that climate affects the behavior and local distribution of this species.

中文翻译：

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寒冷的冬天对野生猛禽的出生扩散距离有特定的影响

扩散是一个关键过程，对物种种群的空间分布、密度和遗传结构具有重要意义。分散策略可能因个体和环境特征而异，但很少考虑到假定的表型与环境的相互作用。基于黑色素的颜色多态性是与特定行为和生理特征相关的表型特征，因此是研究不同环境中分散策略的良好候选特征。在这里，我们使用 40 年的一组颜色多态黄褐色猫头鹰 (Strix aluco) 的数据集，研究了与羽化后的冬季温度和个体特征相关的灰色和褐变红棕色（以下称为棕色）颜色形态的出生扩散距离. 因为变形对寒冷的冬天有不同的敏感性，我们预测变形的出生扩散距离会根据冬季条件而变化。冬季温度不影响新兵中棕色（或灰色）的比例。我们发现，在这两种形态中，扩散距离与冬季温度的相关性相反。虽然灰色变种在更恶劣的条件下进行更大的运动，可能是因为它更好地应对冬季的严酷，但当冬季更严酷时，棕色变种会分散更短的距离。我们在变形之间争夺领土的背景下以及这些替代策略的成本和收益方面讨论了这种特定于变形的出生分散模式。