Hagsign

Hagsign is the way a River Hag warns people that the area of a river belongs to her. It is pretty obvious if you know what to look for... usually the skeletons of river animals draped in duckweed or something like that. They aren't plastered in the middle of highways but they are there if you have the brains to look for them. River Hags aren't stupid. They'd rather keep you away than have to maul you.