I have started feeding the birds. So far I have attracted gold finches, house finches, cardinals, house sparrows, chickadees, bluebirds, and the entire neighborhood population of cats!!! They hide out in my bushes and flower patches waiting for the opportunity to pounce. I have placed the feeders high in the trees but don't want my yard to become the neighborhood kitty bar. Short of Scarecrow sprinklers, is there any way to keep the cats out?