A Strange Gathering of Crows

I was in my studio and I heard a great racket outside. Went to take a look and there were a bunch of crows gathering and talking up in this tree on the other side of the street. It was raucous for quite a while then they all flew off. I've never seen or heard anything quite like this before. They say crows are very intelligent. It might have been a meeting of some sort for warning each other about some kind of danger.