Just read a few other postings that suggested it could possibly be bats. Never thought of that possibility, but it sure makes sense!

Wow, I would love to see bats at the feeder. I think that's kind of cool.

I have lots of deer, racoon, etc. I was sure the culprits were racoon and set a live trap; caught a racoon and the feeders were ok for a while. My feeders were on a couple of 2x6s on top of three posts. If I plug the electric fence up around those posts, racoons will leave alone until I unplug it. Don't think bats would worry about my electric fence. I do have plenty of bats in the area, too. Flying squirrels have bothered my feeders at another residence (did not knock down). The racoons have knocked 6 or 8 feeders down at night without damaging them. They did put one small hole in one feeder that I siliconed.

Forgot, I did put a camera out and got pics before using the live trap. If you don't have a game camera, maybe you could borrow one from someone.

I vote for the raccoons.

I vote raccoon too.