Data from: The influence of wing morphology upon the dispersal, geographical distributions and diversification of the Corvides (Aves; Passeriformes)

New species are sometimes known to arise as a consequence of the dispersal and establishment of populations in new areas. It has nevertheless been difficult to demonstrate an empirical link between rates of dispersal and diversification, partly because dispersal abilities are challenging to quantify. Here, using wing morphology as a proxy for dispersal ability, we assess this relationship among the global radiation of corvoid birds. We found that species distributions are associated with wing shape. Widespread species (occurring on both islands and continents), and those that are migratory, exhibit wing morphologies better adapted to long-distance flight compared with sedentary continental or insular forms. Habitat preferences also strongly predict wing form, with species that occur in canopies and/or areas of sparse vegetation possessing dispersive morphologies. By contrast, we found no significant differences in diversification rates among either the migratory or habitat classifications, but species distributed in island settings diversify at higher rates than those found on continents. This latter finding may reflect the elevated dispersal capabilities of widespread taxa, facilitating the radiation of these lineages across insular areas. However, as the correlations between wing morphology and diversification rates were consistently weak throughout our dataset, this suggests that historical patterns of diversification are not particularly well reflected by present-day wing morphology.已知种群在新区域扩散并定居后，有时会催生新物种。然而，要证实扩散速率与物种分化速率之间的经验关联始终颇具挑战，部分原因在于扩散能力难以量化。本研究以翼形（wing morphology）作为扩散能力的替代指标，针对鸦科鸟类（corvoid birds）的全球演化辐射类群，分析二者间的关联。研究发现，物种分布与翼形密切相关：同时栖息于岛屿与大陆的广布物种，以及迁徙物种，其翼形相较于定居性大陆物种或岛屿定居型物种，更适配长距离飞行。栖息地偏好同样可显著预测翼型，栖息于林冠层或稀疏植被区域的物种，多具备利于扩散的翼形。相较而言，本研究未发现迁徙类群或不同栖息地类群间的物种分化速率存在显著差异，但岛屿分布物种的分化速率显著高于大陆分布物种。这一结果或许反映了广布类群较强的扩散能力，推动其演化支系在岛屿区域实现辐射演化。不过，由于本数据集内翼形与分化速率间的相关性始终较弱，这表明现生翼形并不能很好地反映物种的历史分化模式。