Suspected anti's huh? That could be, or maybe they are hunters themselves and are jealous that you are hunting on that land!!! I agree that you should sit close and get it on film when they vandalize your vehicle.
I had a runin with an anti the other day. I was down on our property along the fencline where there is a house about 100 yards from the fence. I was trying to figure out where to set up a ground blind for this week and here comes Mrs. Anti-Hunter herself. Before i could say anything she said "can i help you?" then i said uhhh, can i help you? She then proceeded to ask me if i was supposed to be down there and I said yeah, my parents own the land. She said are you sure? And i said yeah, you see this fence right here and that creek over there? She had a stupid look on her face and i said well we own from the road between the fence and the creek all the way down till the creek and fence meet. She asks for my name and i tell her and she rolled her eyes at me and asked me if my dad was involved with law enforcemnt? I replied yes. She then said i dont like hunting nor people involved with hunting. I dont want any deer being shot down here. I moved out here to get away from that and i like to watch the animals. These are MY ANIMALS and i dont want them being killed. I said well mam, the first owner of these animals is god and the second owner is the state of iowa, not you!!! Then i said there is going to be hunting on this side of the fence. She didn't like that comment too much and she said mr. mccausland, im not going to be an easy neighbor to get along with... I said to her, thats too bad mam. She began walking away and i said by the way mam, harassing hunters is illegal. She said coming on to my property is illegal too!! I said i know it is, but if i have a blood trail to follow and it comes on to your property, state lawa says that i can track a wounded animal on your property as long as i dont bring my weapon. She said you cant if i put up no tresspassing sign's on the fence, and if you do i will call the police. Then i said, well mam, if that is the case, I will call the game warden and he will assist me on tracking the animal on your property. She stormed off after that and I said have a nice day mam. She fliped me the bird!

Cool head wins the battle every time!!!
I personally wouldn't retaliate on them guelph299, because that can cause more trouble. Let the authorities handle it!!!