Did you know that parrots are one of the few animals with flourescent feathers? Well, you can't see it with the naked eye, but they know it's there. These budgerigar parrots, illuminated here with UV light (like that sweet blacklight you would use at college parties), use their appealing plumage as a sexual signal; according to a recent study, females may prefer males with brighter plumage.

Dr Kathryn Arnold, University Research Fellow and Dr Mark Neville from the University of York via Royal Society