Bird that sounds like a smoke detector low battery?

Last few weeks we've had this bird (or other animal) that chirps crazy loud that sounds like a smoke detector low battery. Regular intervals of about one chirp every 4 seconds.

Goes on for about 5 to 30 minutes a few times a day. We live in the great hills area and we do have a shit ton of birds in the area, including a bunch of hummingbirds which Google says it might be.