The Blue Jay is a fairly large bird about 10 inches in length. It is commonly seen east of the Rocky Mountains. Males and females look the same. They are aggressive birds; generally, when they are on a feeder, other birds stay away until the Blue Jay leaves. Although cats like to catch birds, when a Blue Jay sees a cat, it will often swoop at it and frighten it away. It likes sunflower seeds but it doesn't have the "tooth" that the Cardinal has. To open a sunflower seed, the Blue Jay will perch (either on a feeder perch or a tree limb); it will place the seed between its feet and peck at it with its beak until the hull splits open. If your feeder has wooden perches, you will eventually have to replace them because this pecking slowing erodes the perch.