Bioluminescence and biofluorescence are some of the coolest visible natural phenomena.

There are no pics in the article, so if you want to see the fluorescence, you need to check out the original research paper which is linked, but I’ll also link it here:

https://royalsocietypublishing.org/doi/10.1098/rsos.241905

Be warned that dead birds were used for the research, but also no need to worry, because preexisting specimens from an ornithology collection at the American Museum of Natural History (AMNH) in New York were used, meaning no birds were killed for the research.