Right after hanging this on a tree with screws, I saw the squirrels attack it.  I don't believe they were ever able to get any food and eventually they gave up.  But they did bend the flimsy metal around the tray and it doesn't open a close properly anymore.  Also, it is way too heavy to hang from a typical shepherd's hook used for bird feeders.  The first one I hung it one was steel pipe and did not bend, but the weight being all on one side caused the whole thing to fall over.  The "springy" shepherd hook hangers simply bend way over under all the weight.  So I screwed it into a tree trunk.  Now it is hard to get it to come apart to refill.  You have to jiggle and push and twist etc until it finally lifts out.  Putting it back in is not easy either.
Right after hanging this on a tree with screws, I saw the squirrels attack it. I don't believe they were ever able to get any food and eventually they gave up. But they did bend the flimsy metal around the tray and it doesn't open a close properly anymore. Also, it is way too heavy to hang from a typical shepherd's hook used for bird feeders. The first one I hung it one was steel pipe and did not bend, but the weight being all on one side caused the whole thing to fall over. The "springy" shepherd hook hangers simply bend way over under all the weight. So I screwed it into a tree trunk. Now it is hard to get it to come apart to refill. You have to jiggle and push and twist etc until it finally lifts out. Putting it back in is not easy either.