[jellicle]

Jim Corbett was a Brit in India who had the job of hunting down a number of man-eating tigers, lived to tell about it, and wrote several books about it (recommended). He talks extensively about listening to the jungle as a tiger detection method - the monkeys freak out and call to warn each other about the predator, birds freak out and then disappear, etc. He paid attention to both unusual silences and unusual noises. There were still several occasions where he almost became tiger chow.