You think you've got clever squirrels? Check this out:https://www.youtube.com/watch?v=nWU0bfo-bSYEver seen it before? Crazy!
I've defeated squirrel poaching of birdseed by suspending the feeder by a wire from a tree branch above my deck and threading a vinyl 33 1/3 RPM LP record on it, resting on the feeder itself. Just got to be sure nothing is close enough for the squirrel to jump from, either below or to the side.