The Origin of Species

On beauty and birds:

I can see no good reason to doubt that female birds, by selecting, during thousands of generations, the most melodious or beautiful males, according to their standard of beauty, might produce a marked effect.

Charles Darwin
The Origin of Species (1859)

It’s interesting to think that when we see a bird, a male cardinal for example with his bright red colors and sharp-pointed head, we are seeing the culmination of generations of choices by females of what they think is melodious and beautiful. Even within what Darwin calls the struggle for survival there is room for beauty.