Data from: The evolutionary origin of variation in song length and frequency in Cettiidae warblers

Aspects of bird song have been shown to correlate with morphological and ecological features, including beak and body size, and habitat. Here we study evolution of song length and song frequency among 30 species belonging to the Cettiidae. Frequency is negatively correlated with body size, and song length increases with latitude. Although migration distance correlates with latitude, the association of song length with latitude is only present within the non-migratory species, implying the association is not a consequence of migration. We place these correlations in a historical framework to show that the body size-frequency association arose early in the group, but the latitude-song length association is more evolutionarily labile. We suggest that latitudinal correlates of song length may reflect increased importance of sexual selection by female choice.

已有研究证实，鸟类鸣唱的多项特征与其形态学、生态学特征存在显著关联，这些特征涵盖喙部与体型大小以及栖息环境。本研究针对隶属于树莺科（Cettiidae）的30个物种，探究其鸣唱时长与鸣唱频率的演化规律。研究结果显示，鸣唱频率与体型大小呈负相关，而鸣唱时长则随纬度升高而增加。尽管迁徙距离与纬度存在相关性，但鸣唱时长与纬度的关联仅存在于非迁徙性物种中，这表明该关联并非由迁徙行为所导致。我们通过历史演化框架对上述相关性展开分析，结果表明体型与鸣唱频率的关联在该类群演化早期便已形成，而鸣唱时长与纬度的关联则在演化过程中更易发生变化。我们推测，鸣唱时长与纬度的相关性，或许反映了雌性选择介导的性选择作用的重要性有所提升。