It's not just what you have, but how you use it: solar-positional and behavioral effects on hummingbird color appearance during courtship

Animals exhibit a diversity of colors that can play key roles in mating interactions. However, we presently lack an understanding of the relative importance of the environment, behavior, and natural reflective properties of colorful ornaments on an individual’s color appearance during mating-displays. We investigated interactions among structurally-based plumage, display environments, and courtship shuttle displays of male Costa's hummingbirds (Calypte costae) to test how these elements may differentially contribute to color appearance during shuttles. Male position relative to the sun was the strongest predictor of color appearance, with shuttle behaviors and feather reflectance playing smaller roles. Further, male solar orientation and shuttling behavior (e.g. shuttle width) were repeatable among displays, whereas male color appearance mostly was not. These results emphasize the contributions of behavior and environment to color-signaling and suggest that relying on reflectance measur...动物拥有多种多样的体色，这些体色在交配互动中可发挥关键作用。然而目前我们仍未明确，在个体交配展示期间，环境、行为以及彩色饰羽的自然反射特性，各自对其体色呈现效果的相对重要性究竟如何。我们以雄性科斯塔蜂鸟（Calypte costae）为研究对象，探究其结构型羽衣、展示环境与求爱穿梭展示之间的相互作用，以验证这些因素在穿梭展示过程中对色彩呈现的差异化贡献。研究发现，相较于穿梭行为与羽毛反射特性，雄鸟相对于太阳的位置是影响其色彩呈现的最强预测因子。此外，雄鸟的太阳朝向与穿梭行为（如穿梭宽度）在多次展示中具有可重复性，而其色彩呈现则大多不具备这一特性。上述研究结果凸显了行为与环境在色彩信号传递中的作用，并表明仅依赖反射率测量[...]