When we lived in town there was a family of crows that lived in a tree in our yard. The people that moved out of the house warned us that the crows were very "active" and would go so far as to swoop down on them when they were coming and going from the house. They were so agitated by this they they tried to get rid of them by throwing things at the nest, hoping that if they could get rid of the nest they could get rid of the crows from the yard for good.
They never did manage to get rid of the nest.
The whole time we lived there the birds never bothered us once.
Here is an article from the NYtimes revealing that crows remember faces. Check it out here.
Oh, how we underestimate the animal kingdom.