Sorry, Phil, but he has as much right to live on his land as you do on yours. If a Chumash indian knocked on your door and said that you are on his land, would you just up and leave? ;) Are you a "squatter"?
I am in a similar, but smaller, position as the Bundy's. I don't know how much land they own, but we own 10 acres totally surrounded by BLM and AZ state land. If I had more cattle than could graze on my land, I can pay a fee to allow them to graze on the government managed land. It's a win/win situation in that I could feed my cattle more cheaply and the wild grasses are kept mowed which lessens the likelyhood of wildfires.
LS