Data: Morphological and ecological predictors of migration in shorebirds (a phylogenetic perspective)

Migration is the synchronised movement of a large part of a population from breeding to non-breeding grounds driven by seasonal variation of resources and avoidance of harsh winter conditions. Migration is a central component of many species’ life histories, including birds, mammals, fishes, and invertebrates. However, the interplay of ecological and evolutionary drivers of migration has long intrigued biologists and remains contentious. Shorebirds represent a valuable group for testing multiple predictors of migration, as they demonstrate a range of morphological and ecological characteristics (e.g., wing shape and habitat breadth), and a large proportion of shorebird species migrate. Here we tested whether breeding site climate, wing shape, body mass, and number of habitats occupied can predict migration across 196 shorebird species using novel Bayesian regression modelling allowing explicit decomposition of trait correlations into both phylogenetic and non-phylogenetic components. Increasing climate seasonality and pointier wing shapes favouring dispersal appeared strongly associated with migration, matching our predictions and potentially reflecting resource availability optimisation and the energetic costs of migration. Higher number of habitats occupied also appeared associated with migration, perhaps reflecting selection to decrease the specific habitat requirements of migration transits. The lack of a significant relationship for body mass may reflect conflicting selection pressures, as migration efficiency (energetics) increases with body size but migration duration (and time that can be spent at breeding sites) decreases.迁徙是指种群中大量个体因资源的季节变化以及躲避严酷冬季条件，同步从繁殖地迁往非繁殖地的行为。迁徙是包括鸟类、哺乳类、鱼类以及无脊椎动物在内的诸多物种生活史的核心组成部分。然而，迁徙的生态与进化驱动因素之间的相互作用长期以来一直令生物学家着迷，且至今仍存在争议。滨鸟（Shorebird）是检验迁徙相关多种预测因子的理想类群，因其展现出多样的形态与生态特征（如翅形与生境广度），且很大一部分滨鸟物种均会进行迁徙。本研究针对196种滨鸟展开分析，借助可将性状相关性明确拆解为系统发育与非系统发育两个组成部分的新型贝叶斯回归模型（Bayesian regression modelling），检验繁殖地气候、翅形、体重以及占据的生境数量是否能够预测其迁徙行为。研究结果表明，气候季节性增强以及利于扩散的尖削翅形与迁徙行为显著相关，这与我们的预测一致，或反映了对资源可用性的优化配置以及迁徙过程中的能量成本。占据更多生境同样与迁徙行为存在关联，这或许反映了自然选择压力促使物种降低迁徙过境阶段对特定生境的需求。体重与迁徙行为未呈现显著关联，这可能源于相互冲突的选择压力：一方面，体型越大，迁徙效率（能量代谢层面）越高；另一方面，体型增大会缩短迁徙时长，进而减少可用于繁殖地活动的时间。