Niagara Falls' Botany - swarm

This is one of the oddest things I've ever seen -- it appeared at first to be some sort of banner, but as I looked more closely, I saw that it was actually some sort of bug swarm, trapped or guided by wind currents around the corner of the building. I also took a short movie of it, which is less distinct, but conveys the sense of movement a good deal better (natch!)

The swarm formed and dissolved almost regularly, like a pulse -- moving from nearly solid-looking to nearly invisible as the insects moved apart. It lasted for at least ten minutes, but was gone when we returned at dusk.