Squirrels!!!

We seem to have a very healthy population of ground squirrels. They are driving the cats crazy. They sit by the fence dreaming of chasing and catching them while the squirrels play in the wood pile. Our cats have a large cat fenced area where they can exercise and watch the squirrels and pigeons. They can't get them, which I'm sure is frustrating, but we look at it as "cat TV" being entertaining to them.