Michelle & Susan, you are both just to kind. Become an concerned citizen & make a citizens arrest, become an aux inforcement officer. Find out if they park on your land, can you clamp/boot their car/truck & can you charge them for it's return. On reservation land where they have their own law enforcement the local game warden conficates every thing, vechiel, fishing poles or firearms, whatever's in the vechiel & whatever's on their person. Post that "TRESPASSERS HUNTING WILL BE SHOT". Doesn't matter if it's true or not. If some one's parked & waiting, like Garg, let the dogs out & cover their ass with your own weapon, I know that's a bit extreme but shoting assholes is fair play. If they do manage to bag a buck take pictures of them, the game, their vechiel & the posted signs, then take the game too. If they're stupid enough to hunt on posted land or if they're so stupid they can't read then they're stupid enough to fall into your hands & will have to deliver up to you & the law what's demanded of them. After the embrassment of their actions are known it's likely that you'll be left alone soon enough. A few more dogs wouldn't be hurt either, trained dogs, pointers & retrievers. Big time law suit for a hunter shooting one of those.
Good luck this hunting season, you can probably bag at least one hunter each season, it's your turn now.

Barry