Several ecogeographical ‘rules’ have been proposed to explain colour variation at broad spatial and phylogenetic scales but these rarely consider whether colours are based on pigments or structural colours. However, mechanism can have profound effects on the function and evolution of colours. Here, we combine geographic information, climate data and colour mechanism at broad phylogenetic (9,409 species) and spatial scales (global) to determine how transitions between pigmentary and structural colours influence speciation dynamics and range distributions in birds. Among structurally coloured species, we find that rapid dispersal into tropical regions drove the accumulation of iridescent species, whereas the build-up of non-iridescent species in the tropics was driven by a combination of dispersal and faster in situ evolution in the tropics. These results could be explained by pleiotropic links between colouration and dispersal behaviour or ecological factors influencing colonization success. These data elucidate geographic patterns of colouration at a global scale and provide testable hypotheses for future work on birds and other animals with structural colours.

人们提出了几种生态地理学“规则”来解释广泛的空间和系统发育尺度上的颜色变化，但这些规则很少考虑颜色是基于色素还是基于结构颜色。然而，机制可以对颜色的功能和演变产生深远的影响。在这里，我们结合了广泛的系统发育（9,409 个物种）和空间尺度（全球）的地理信息、气候数据和颜色机制，以确定色素和结构颜色之间的转变如何影响鸟类的物种形成动态和范围分布。在结构彩色物种中，我们发现，快速扩散到热带地区推动了虹彩物种的积累，而热带地区非虹彩物种的积累是由热带地区的扩散和更快的原地进化共同驱动的。这些结果可以通过颜色和分散行为之间的多效性联系或影响殖民成功的生态因素来解释。这些数据阐明了全球范围内颜色的地理模式，并为未来对鸟类和其他具有结构颜色的动物的研究提供了可检验的假设。