Why do birds sing?

This morning, like all mornings, the mockingbird that lives in our garden, was singing. Yes, is is music. Or rather, language that sounds like music. Language of emotion, competition and power.

Our mockingbird sings, waits a moment for an answer from another bird in the bushes next door, and sings again. If the answer doesn't come immediately, our bird will sing its song a bit louder or with a few extra notes.

When it sings the same notes over and over again, there is no response. Our bird comes up, with emphasis, with a new song. Yes, the other bird answers with the new song. This goes on and on.
The message: change your song and you will get the attention. The singing often sounds like a contest and inventing new songs to appeal to followers. Maybe it is "what you can do, I can do too".
The new songs and the many variations, will help the males to impress the females.

listen here: youtube link
I recorded some mockingbird songs. When I play them loudly, a bird comes to my window and starts repeating the song. But after a while, the bird looses interest.

Watch why birds sing:


Yes, most bird songs are beautiful. Doesn't beauty count in nature? Yes, it does.
Watch Birds of Paradise: