So I have a Parallax PIR sensor and I have it lined up pointing out of a patio door towards a bird feeder. It's obviously not sensitive enough because it doesn't trigger from birds but it does trigger from people. Are there any alternatives out there that would be sensitive enough to detect a bird?
(haven't tried it, but...) Perhaps the new Parallax X-Band motion detector? ($30)
I know nothing about differences in sensitivity, but if you haven't looked at it you probably should.
Wow, that looks promising!
If you try it, be sure to post your findings here. I'd be interested in such a device.