I was amazed, I didn't think they were this strong, but in only a couple weeks time, squirrels ate through the TOP plastic covor of the birdfeeder, not the clear plastic seed viewing area, but the top covor of it. And I had it hanging a couple feet below the branch but that didn't stop them. Right now there is a 2" hole in the plastic top of my birdfeeder that was eaten away by the squirrels and sometimes I actually see a squirrel inside the feeder. I haven't heard of this before, but I guarantee it happened to me.Now I'm looking for a new feeder but among other squirrelproof things I want them to have, they HAVE to have a metal top and specify it in the description, the squirrels (or maybe they're super-squirrels) ate through the plastic top of my current feeder.