A squirrel baffle is a device designed to deter squirrels, raccoons and other small mammals from accessing birdfeeders to retrieve birdseed. They are typically mounted on the pole of a birdfeeder, at a height to which squirrels cannot jump.
Squirrel baffles vary in design. One type may employ a rotating cylinder to destabilize the climbing surface, while another will feature a large round tube difficult for a squirrel to grab onto. Other designs include tapered cones and sloped disks. Many squirrel baffles are made of painted metal or plastic, in order to create a slippery surface.
The roof of a hanging birdfeeder can also be designed to act as a baffle to prevent squirrels from jumping down onto the feeder.
Providing an alternate equivalent food source in conjunction with a squirrel baffle is often the best way to minimize unwanted visits to a birdfeeder. There are many squirrel feeders available, as they love to eat all sorts of food.
Typically, those who feed birds need to follow the rule: "5-7-9". That is to say, the feeder should be at least five feet off the ground, seven feet away from perches (that could be used as a launch pad), and nine below branches.
Source of the article : Wikipedia