I assume you have the place well-posted.
Sad, isn't it, the people will resort to breaking the law for the sake of a "sport"?
I've never had the problem on the little bit of private ground I can hunt.
Only solution is to try to prosecute to the fullest extent of the law. Hope you have a cop and/or prosecutor who is a hunter and can appreciate the violation.
Don't resort to the self-help of shooting a gun at the trespassers as some have (I hope jokingly) suggested. You don't want to actually hurt another human, I would suspect, and you certainly wouldn't want the hassle or expense of defending against an assault or murder charge.
(IMHO, even suggesting such conduct is a poor/bad joke.)
If you invite me, I'll stake out your territory all season long, until you've shot your bird(s), and I'll run off any trespassers. (Joke.)
Good luck when you get to go!!