The Royal Wing Stacker Bird Feeder is an excellent addition to your feeding habitat. Stacker style feeders are often preferred by many bird enthusiasts because they're so easy to use, and they allow you to mix and match flavors. This is because each bird feeder can hold up to 4 bird snack stackers at a time. Make all 4 the same flavor, or switch it up to appeal to a larger variety of bird species. Bird food sold separately.