Nobody is really talking about what you do with the windmill blades when they are worn out - you can't easily recycle, reuse, or otherwise dispose of them. Throwing them into a landfill, essentially forever, seems the only option for now.
There are places where they are having problems with predators - coyotes and so on, because the birds get killed flying through them, and then the predators/scavengers have learned it is easy meals there.