Openings in the wire shroud align with seed ports and provide birds access to the seed. When a squirrel climbs onto 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.
Remember it's the squirrel's weight that triggers the closing mechanism. If a squirrel can reach over from a nearby foothold and avoid placing weight on the feeder, then the squirrel will have access to the seed ports! Allow for at least 18 inches of clearance around the feeder. This will force the squirrel to climb onto the feeder, thus triggering the closing mechanism.
Dimensions: 7.5" W (including perches) by 10.75" H (+ 9.25" hanger). By Brome Bird Care.