Two ways to display: male hummingbirds show different color-display tactics based on sun orientation

Animals exhibit a diversity of ornaments and courtship behaviors, which often co-occur and are used for communication. The sensory drive hypothesis states that these traits evolved and vary due to interactions with each other, the environment, and signal receiver. However, interactions between colorful ornaments and courtship behaviors, specifically in relation to environmental variation, remain poorly understood. We studied male iridescent plumage (gorgets), display behavior, and sun orientation during courtship flights (shuttle displays) in broad-tailed hummingbirds (Selasphorus platycercus), to understand how these traits interact in both space and time to produce the perceived coloration of males. We also tested how gorget coloration varies among males based on their plumage, behavioral, and morphological characteristics. In contrast with previous work on other animals, we found that displaying males did not directionally face the sun, but instead displayed on a continuum of solar o...