Melodies of Singing Birds: Result of a Rare Evolutionary Event

Over millions of years, sound production was taken over by the syrinx, possibly because the syrinx was much better in producing varieties of sounds.

Ancient Birds Avoided Mass Extinction By Shrinking

These songbirds sing for hours a day to keep their vocal muscles

Bird - Wikipedia

Nature: Some East African sunbirds have been singing the same song

Statistical Evolutionary Laws in Music Styles

Evolution of Feathers

At 67 Million Years Old, Oldest Modern Bird Ever Found Is Natural

Ho-Oh (Pokémon) - Bulbapedia, the community-driven Pokémon

For Tropical Bird, Violin More Resonant Than Aria

Meet robots on a mission to help birds

A Wealth of Knowledge from an Everyday Bird