On another post several have been talking about predation etc. With technology the research is getting pretty cool. So about 20 years ago I thought about having a device for a hunter that could put in the woods to monitor gobbling. Of course it was not gonna happen for anything we could afford. Check out this research they are doing in Kentucky using a Audible or Sound Listening device. They are about a grand so not anything you will have for yourself but pretty neat stuff happening.
Good 25 minute watch or listen
https://www.youtube.com/watch?v=MQYdkhRBF9c