Crows are fascinating creatures. My wife read that they will chase hawks and eagles away, so she started putting food out for the crows near the tree where they gather (we have chickens and ducks that we don't want the hawks near).

Now they bring trinkets as gifts and leave them near the tree. We also had a crow in the past that would make barking noises when it saw our dogs and freak them out. I'm convinced it was messing with them.