Male birds-of-paradise have a lot of tools in their arsenal for attracting potential mates: bright feathers, elaborate dances and, according to new research, the ability to glow.
Scientists have found that 37 of the 45 species of the tropical forest birds are capable of biofluorescence - that is, their feathers absorb blue or ultraviolet (UV) light and emit it back out at lower, visible frequencies.
“It seems fitting that these flashy birds are likely signaling to each other in additional, flashy ways,” says Rene Martin, the lead author of the study and a biologist at the University of Nebraska-Lincoln.
Males were biofluorescent in areas that would be prominent during mating displays, such as the feathers on their head, neck, tail or belly, as well as the inner mouth, throat, bill and feet. Females also emitted a glow, primarily on the belly and chest. The fact that biofluorescence was more present in males than in females, ties into the idea that the glowing feathers are used to attract mates.
“What they’re doing is taking this UV color, which they can’t see, and re-emitting it at a wavelength that is actually visible to their eyes,” explains the New York Times. “In their case, it’s kind of a bright green and green-yellow color.”
“Even a charismatic group like the birds-of-paradise that have been studied extensively can still offer new insights into avian vision, behavior and morphology,” says Rene Martin.
Th findings were published in the journal Royal Society Open Science.