Owls can’t move their eyeballs.
That’s because owls don’t have eyeballs at all. Instead, their eyes are shaped like tubes, held rigidly in place by bones called sclerotic rings. (Human eye sockets, which hold spherical eyes, do not have sclerotic rings.)
Because owls can’t roll their eyes around the way we do, they have to move their entire head to get a good look around. They frequently twist their head and “bob and weave” to expand their field of view. Owls can turn their necks about 270° in either direction, and 90° up-and-down, without moving their shoulders!