It took the squirrels over a year of trying, but they did learn how to defeat my spinning bottom bird feeder. ( Yankee is the brand.). The feeder was hanging from a shepard's hook and the squirrel grabbed the vertical portion of the hook with his two back paws and with one front paw held on to a non spinning nut on the very bottom of the feeder. The free hand raided the feeder. They won. No large tree was available to move the feeder to, so I bought a Slinky spring toy and ran the hook through the toy, attaching the slinky at the very top of the hook with the spring falling to the ground thus covering the entire vertical portion of the hook. I won, at least temporarily.