What are the purple, triangular-cylinder shaped things I keep seeing hanging from trees?

I would guess that the they are roughly 2.5' tall by 1' wide. They are royal purple in color. It's hard to tell what material they are made from, but my best guess would be some kind of nylon. I live in a rural area, and I'm seeing them hung up all over the place now. I wondered if these are some sort of new bat house or bird house?