I read a passage in a book growing up, I can't remember what book it was, but it was about how crows are only black to humans, they can see different colors than we can so they're very colorful to each other, covered in all sorts of brilliant colors.

Another fun fact: bees can see utraviolet, and flowers are "designed" for bees, so many of the patterns are invisible to humans, but visible under UV photography:

https://en.wikipedia.org/wiki/UV_coloration_in_flowers

https://www.wildflower.org/magazine/native-plants/a-differen...