I think you are on the right track. Definately ask the owner if he allows others to hunt on the property. If he says yes, ask them if they had ask for permission to hunt before you did. If they had first crack at the ground then it doesn't look like there will be much for you to do. Unless you ask him if you can exclusively lease the land or something. But then you might be stepping on the toes of the other hunters.

If he claims he hasn't let anyone else onto the property, ask him if you can put up any kind Trespassing or No Hunting signs. Then again, a signdoesn't always stop people from hunting when they havealready trespassed in the first place.

After that, I don't know what else youcould do, maybe talk to the owner and ask if you can havesomeone keep an eye on the land, like a conservationofficer. I don't know if the landowner wouldgo for it, but it is wortha shot.

Basically if he allows other onto the land there isn't much you can do but ask him to lease the land outright. But once again, as stated above, you may be stepping on some toes, especially if they were there first.