I think some of what I find might be the result of wind blowing through campsites, but I'm also pretty sure most of it is just humans being shitheads. Want to know something interesting I often find hiking out in the wilderness? The remains of mylar balloons that used to be filled with helium. That's where they end up when people let 'em fly.
Those deer legs were bizarre. Strange enough that they were there, even stranger that I pitched my tent right next to them and didn't even see them till after dark. Maybe they actually didn't appear until the night arrived…