Thousands of delighted bird lovers have confirmed it: Brome's Squirrel Buster technology is truly squirrel proof! With four perches and a protective grid, it'll attract perching and clinging birds while the patented technology thwarts squirrels and large birds. As an added deterrent to large birds, the perches can be removed to allow only clinging birds to use the feeder. Openings in the wire shroud align with seed ports and provide access to the seed. When a squirrel climbs on the feeder, its weight automatically forces the shroud down, closing access to the seed ports. All squirrels and many large birds are foiled but not harmed in any way. The feeder dismantles easily and without any tools so cleaning is virtually effortless.