With bird sounds, but for the love of god, don't put the bird sounds, like, in rhythm with the song.
Put, like, 1 at the beginning.
And then at that section where the flute (or whatever it is) cuts out, and it's plain for a few seconds, and then it comes back in with strings.
Put a couple (as in, not many) bird sounds over that part where it's "simpler."
And maybe a few at the end.