Keep squirrels away from a bird feeder with squirrel baffles, wire cages and changes to the mounting system. Another option is to set up a separate feeding area for squirrels away from the bird feeder.
Squirrels can climb easily and jump significant distances ﾖ up to 10 feet or more in one jump. Make the bird feeder difficult to access by jumping to minimize the number of squirrels that steal the birdseed. A slippery metal pole makes it difficult for squirrels to climb all the way to the top. If squirrels still make the trek up the pole, add squirrel baffles, which are special sloped features that go onto the pole and make it difficult to climb.
Another option is to hang the bird feeder on a wire away from low branches or other structures. Slide small sections of pipe or thread spools on the wire so that they spin when the squirrel attempts to walk along the wire.
Some bird feeders come with wire cages to prevent squirrels from getting close while still allowing birds to reach the birdseed. Other bird feeders come with doors that close when the weight of a squirrel is on the bird feeder.
If you don't mind having the squirrels in your yard, consider setting up a squirrel feeder in another area. Squirrels like peanuts, corn and sunflower seeds. Leave those items out, or buy a squirrel feeder to control what and where the squirrels eat in your yard.