When a Northern Saw-whet Owl spreads its wings, many birds can see something our human eyes can’t: the owl’s flight feathers glow with ultraviolet light. It’s invisible to humans without the help of a UV blacklight. While the glowing feathers on parrots might help them attract mates, the reason for the owls’ glowing feathers still isn’t clear. However, scientists realized that they could estimate an owl’s age based on the pattern of luminescent color on the wings, which changes predictably as birds grow and replace their feathers.

More info and transcript at BirdNote.org. 

Want more BirdNote? Subscribe to our weekly newsletter. Sign up for BirdNote+ to get ad-free listening and other perks. 

BirdNote is a nonprofit. Your tax-deductible gift makes these shows possible.