Data from: Environmental variability and acoustic signals: A multilevel approach in songbirds

Among songbirds, growing evidence suggests that acoustic adaptation of song traits occurs in response to habitat features. Despite extensive study, most research supporting acoustic adaptation has only considered acoustic traits averaged for species or populations, overlooking intraindividual variation of song traits, which may facilitate effective communication in heterogeneous and variable environments. Fewer studies have explicitly incorporated sexual selection, which, if strong, may favour variation across environments. Here, we evaluate the prevalence of acoustic adaptation among 44 species of songbirds by determining how environmental variability and sexual selection intensity are associated with song variability (intraindividual and instraspecific) and short-term song complexity. We show that variability in precipitation can explain short-term song complexity among taxonomically diverse songbirds and that precipitation seasonality and the intensity of sexual selection are related to intraindividual song variation. Our results link song complexity to environmental variability, something previously found for mockingbirds (family Mimidae). Perhaps more importantly, our results illustrate that individual variation in song traits may be shaped by both environmental variability and strength of sexual selection.在鸣禽（songbirds）类群中，越来越多的证据表明，鸣唱性状的声学适应（acoustic adaptation）是为响应栖息地特征而发生的。尽管已有大量相关研究，但绝大多数支持声学适应的成果仅考虑了物种或种群水平上的平均声学性状，却忽略了鸣唱性状的个体内变异——而这类变异或可助力异质且多变环境中的有效通讯。仅有少数研究明确纳入了性选择（sexual selection），若性选择作用较强，则可能会倾向于塑造不同环境下的性状变异。本研究针对44种鸣禽，通过探究环境变异性、性选择强度与鸣唱变异（个体内变异与种内变异）及短期鸣唱复杂度之间的关联，评估声学适应在鸣禽中的普遍程度。研究结果显示，降水变异性可解释分类学多样性丰富的鸣禽类群的短期鸣唱复杂度，而降水季节性与性选择强度则与鸣唱的个体内变异相关。本研究将鸣唱复杂度与环境变异性建立了关联，这一结论此前仅在嘲鸫科（Mimidae）鸟类中被证实。或许更为关键的是，本研究表明鸣唱性状的个体变异或同时受环境变异性与性选择强度的共同塑造。