I'm not sure but I think the quests, 'Path of the Hunter' and 'Wanted Dead' have disappeared before I did them. Because I remember seeing them on the map, but then I proceeded with the story, thinking that I will do them later. But now I don't see them.
I just finished "the man named Hoyt" mission, and so far I have only done one hunting quest, and there is no other. I have unlocked 6-7 radio towers. Or is it normal (i.e. will new hunting quests will appear as I progress?) but I'm 99% sure there were others before.