Fig. 1

During the dive, sound and color change markedly as a function of trajectory and speed. a Representative dive aligned with the origin at the nadir (point of lowest height). The asterisk indicates estimated female position. Colored sections correspond to the sonogram of sonations during the dive. b Sonogram corresponding to the representative dive. Colors indicate sections of dive sonation. Purple: wing-generated main dive sonations (section A). Orange: tail-generated sonations. Teal: wing-generated short sonations (section B). Pink: wing-generated long sonations (section C). c Plot of all tracked dives aligned as above and overlaid (n = 48). d Mean estimated speed during the dive. Shaded area indicates standard deviation (n = 17 bouts of diving containing 48 dives). Also overlaid with transparency are individual measures from all tracked dives (n = 48). e The perceived color of the gorget changes from red to black. Above: Female's relative cone stimulation values, estimating perception of the male's gorget (based on 10 male specimens), as predicted by a hummingbird vision model as a function of male orientation. Negative x values indicate that the beak is rotated toward the observer. Positive x values indicate that the beak is rotated away. Points indicate measured values, lines show smoothing spline interpolation of the mean, and the shaded area indicates standard deviation of the mean. Red: longwave-sensitive cone. Green: mediumwave-sensitive cone. Blue: shortwave-sensitive cone. Magenta: ultraviolet-sensitive cone. Black: double cone. Note that double cone stimulation is not relative to the other cones but to the reflectance standard in each image (0–1). Below: examples of extracted gorget images, and an illustration of the average hue of the gorgets at each orientation (irrespective of intensity/brightness). The arrow represents the direction of perceived color change that occurs for a female at the nadir of the dive; see main text below