In the distance

As I pulled up to a stoplight the other day, I noticed something in the distance. At first, I thought it was smoke, but it seemed to disappear before my eyes. Then it reappeared, a strange, pliable brown cloud. It was a flock of birds, and they were flying in unison. As I watched, they would turn, and disappear from my sight, as I was too far to see them. A moment later, they turned again, and I could see their wings. I watched them shimmer in the distance until the person behind me honked their horn. The stoplight had turned green.