No one owns an animal, however, there is a bit of respect for another hunter involved. I think that it may be possible the other individual didn't see your blind. If he did, he should've left the area, it may not be law, but its the right thing to do. Personally, if I am hunting and come upon someone else in the area that got there before me, I will back out and look for somewhere else. I don't enjoy people walking in my tracks and I won't do it to them.