Amorous male Costa’s hummingbirds seduce females with their speedy “shuttle dances” and flashy purple plumage. But what’s a bird to do if his feathers aren’t as vibrant as his peers’? A new study suggests a simple fix: Better lighting can make even dull males appear dazzling.
When researchers placed a female Costa’s hummingbird in an outdoor cage with a video camera below, it wasn’t long before eager males arrived and began to perform their signature courtship dance. Frame by frame, the researchers mapped out the males’ poses and their angles relative to both the sun and the female. Then, they re-enacted each male’s routine in outdoor locations that mimicked their initial solar orientations, using colored feathers plucked from the performers’ throats. Meanwhile, a special camera that captured light in the same way a bird’s eye would see it, including the ultraviolet part of the spectrum invisible to humans, snapped photos of the moving feathers.
The photos revealed that the best-looking males—at least, as the females saw them—weren’t necessarily the ones with the brightest plumage, the researchers reported this month in Ecology Letters. Males that faced the sun as they danced had more light bouncing off their iridescent feathers, making their purple pop even more than brightly colored males that faced away.
The finding shows that animals can masterfully manipulate their appearance by altering how they interact with their environment. And for male hummingbirds, that means that the right lighting can go a long way.