Birds-of-paradise are already renowned for their elaborate courtship dances and vibrant plumage. After researchers from the American Museum of Natural History and the University of Nebraska-Lincoln examined specimens of all 45 species under blacklight, we now know they’re biofluorescent too.

The study, published in Royal Society Open Science, found that 37 species exhibited biofluorescence, particularly on feathers involved in courtship displays.

Additionally, males often had glowing patches inside their mouths and on their feet, areas prominently displayed during mating rituals. The researchers suggest that biofluorescence may make their visual signals even more effective in the dimly lit rainforests they call home.

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