Traditional silo feeders come in a variety of decorative styles and shapes designed to augment the backyard. The basic components include a tube to contain the seed, a number of feeding stations that also prevent the seed from spilling, a roof to protect the contents and sometimes a cage to deter squirrels and other pests. Silo feeders are usually filled with sunflower or mixed seed and they attract small to medium sized birds such as finches, sparrows, chickadees, cardinals and other birds with beaks designed for cracking husks. Occasionally a large bird such as a jay or a grackle may attempt to feed on a silo feeder but gripping can be hard so they usually prefer to wait for easy pickings under the feeder.