Quote Originally Posted by DocFrance
We're the only ones on Earth that can appreciate the beauty we create, as well as natural beauty. A bird doesn't know that its song is beautiful; to the bird, it's only communication.
And how do you know they don't? Many animals choose mates based on song, or displays of feathers/crests/whatever. The prettier, the more likely the male is to get a mate. It doesn't make sense to say that they choose mates based on something other than beauty in those cases.