That's what you call a group of crows.
There is a park on the way home from work, Crestmoor Park, which abuts a really pricy older neighborhood. Crows, for some reason, particularly like that park. Some days, I see literally hundreds of the big black birds sitting on the grass and in the trees.
One day, as I made the turn onto the street to parallel the park, a murder of crows was sitting on the yard of the house at the corner. I saw them, out of the corner of my eye, start to fidget as I rounded the corner. As I straightened up, from the 90-degree turn, they all took off and flew in the direction I was going.
They not only flew in my direction, they flew with me. I had crows on either side of me, some of them 5 feet off of the ground and less than ten feet away. I could hear the whooshing of their wings, and I could occasionally feel the air they stirred up.
They matched my speed, and flew along with me for a whole block, looking at me in a quizzical fashion as I pedaled along. It was, at once, the coolest and the creepiest thing that had happened to me in a long time.
Eventually, the crows began to peel off, a couple at a time, landing on the grass in the park. Finally, there was just one crow and me, traveling down the road together. I stopped at the stop sign, and the crow banked to the left and landed in the grass with the rest of the murder.
I waved them a cheery goodbye, and continued on.