Sounds like the landowner may have an easement with one of the land trusts or an agreement with a private organization. Is it posted as such and is there contact information? Unless it is owned by a governmental agency (local, state, or federal) there are no laws prohibiting hunting except if it posted under the Landowner Protection Act. You may still be prosecuted for trespassing on any posted property without written permission. You can check with the local tax office and they should have a record of easements on the property.
"When I get to heaven, tie me to a tree
For I'll begin to roam and soon you'll know where I will be..."