Owl pellet dissection time.
Look at all the bones that have been removed (and that's only about half of the pellet)!
I'm sure at one time I knew (but long since forgotten) that that owls produce 2-3 of these pellets a day and each one usually contains bones from about 8 different animals.
I hope my cats are safe from the owl we have nearby at home. The teacher reminded me that owls can attack cats, but I'm hoping there are enough mice around to keep Mr./Mrs. Owl happy.