Scientists studying birds-of-paradise at the American Museum of Natural History discovered that these birds exhibit photoluminescence, a phenomenon where they absorb UV light and re-emit it as visible light, often in green or yellow hues. This biofluorescence, previously found in other species like fish and mammals, had not been identified in birds until now. The study, published in Royal Society Open Science, suggests this visual effect may play a role in their elaborate mating displays.