Ravens and crows are probably the most intelligent birds. A new study shows that ravens are, indeed, capable of abstract thought.
Apparently, if you train a raven to watch you bury food through a peephole, then give them excess food on the other side of the peephole...they'll assume somebody's watching through the peephole and hide the excess food particularly carefully. Even though they can't see if anyone's on the other side.
Always knew they were rascals.