The Serenity feeder's huge 4 lb. capacity is sure to keep hungry birds happy. The wide opening is easy to fill and clean. The Serenity feeder is designed to allow you to Choose Your Birds™ by selecting which seed to serve and adjusting perch length to fit different sized birds. Seed Selection: Simply flip the feeder window to accommodate mixed seed or Thistle/Nyjer. Adjustable Perches: The perches adjust to give the little birds a chance! Being able to adjust the length of your perch lets you control who visits your feeder. Rule of thumb: A shorter perch discourages large, and often less desirable, birds.