This particular squirrel has been coming to the feeder since last fall, and the darn little bugger can empty it out pretty quickly. This spring, I put a door up and the netting to cat proof the patio, so that the cats could hang out out there without me having to worry about them running off.
You should have seen Sadie when I first let her out on to the deck... She's the door dasher and would love to go running off down the stairs and into the stand of trees in the back yard. She was pacing along the edges, pressing her head against the netting, trying to figure out some way to escape. Thankfully, now she's content to just sit out there.
The squirrel, though, quickly learned that the cats were on one side of the netting and the bird feeder on the other, so he stopped running off at the sight of them, and us. He comes by almost every day. The first time Cheddar saw him out there, he ran out and jumped up against the netting, but the cats are so used to seeing him now that they usually just watch. Heck, just the other day, Sadie was paying more attention to a rabbit in the yard than the squirrel that was right above her head!