If squirrels are invading your birdfeeders, you might consider giving them feeders of their own, filled with corn kernels and whole peanuts. Or, install a feeder like this one, which features a built-in baffle, a plastic skirt shield protecting seed access ports. This squirrel-safe item also includes a weight-activated shutoff mechanism that blocks seed access ports if a squirrel gets hold of the feeder perch. With all of these security features, you can hang this feeder anywhere.
About $30; Woodstream