Invasion of the black crows

Today I heard the piercing sound of hundreds of big black crows, as they were flying around the neighborhood. A few weeks ago I saw them in another part of town and was struck by how many there were and how loud they were squawking!
I was so surprised to see they came to this side of town. They were flying from tree to tree, darting through the air like they were out of control. You couldn't miss seeing them, or hearing them. As a matter of fact, cars that were driving up the street were stopped, as the drivers were trying to get a glimpse of them.
They must be looking for food because of the cold weather!