Squirrel-proof bird feeders work in various ways. While some have a motor that's triggered by a squirrel's weight, others have certain materials that make it hard for pests to latch onto. Other common kinds of squirrel-proof feeders are caged feeders and pole-mount feeders. Caged feeders are excellent options because they're chew-resistant. Pole-mounted feeders can be great as long as they're kept away from jumping-off places squirrels can easily access.