This feeder is designed to protect bluebirds and other small birds. Entrance holes on both sides allow the little ones in and keep starlings out. Bluebirds feed inside on berries, fruit, meal worms or insects. Red cup is included to hold the live meal worms. Front plexiglass slides out for cleaning. Two pre-drilled holes on the top and bottom of the feeder lets you easily mount to a post or pole.