The birds are musical, and may be music to your ears (as in metaphorical music) but whether birdsong is literal music seems to be up for debate [1] unless a human records and samples it into such.

Cage is performance art certainly but not, IMO, music. Again it’s something certainly up for debate. [2] But such debate reminds me of a particular South Park episode based in SF.

[1] - http://www.iupress.indiana.edu/product_info.php?products_id=...

[2] - https://youtu.be/WTCVnKROlos