Sorry to hear of your hunt being ruined...he/she was Liberal tree hugger no doubt...
I do not think it was some tree hugger at all. I am thinking an individual or individual that has no respect for others rights. Also trying to scare the birds to a direction they were planning on hunting in.
Here it is different in respect to public/private land. I hunt on paper company lands which is privately owned but open to the public. I had decoys set up 2 years ago in a place where I was calling in some turkeys. Someone driving by saw the turkeys coming into my decoys and set straight across from me and tried to call them. I couldn't shoot if I wanted to as I could not see the other hunter good enough. So I got out of my blind and scared them off. I never tried to call from that spot again.
Last year a friend set up in the same area and had his truck parked where it could easily be seen. Another truck came by and stopped and got out of the truck. A women came walking up and scared the turkeys away from him while a guy was walking the road. He shot one of the turkeys as it tried to cross the road. Some do not have any respect of others or others rights. My friend should of contacted a warden in his case. As here it is illegal to intentional scare game away from another hunter. That might have prevented this from happening again there at least. Who knows??