Our spring bear hunt was taken from us by the tree huggers. So, yes it works in the fall. It's hard to describe, but what you want is the fawn to sound distressed like a predator is already on the fawn. You'll get any big boar in the area come running in ready to fight for the meal.

I use custom calls. Get ahold of this guy and tell him what you want. He makes the best calls i've ever found.

http://rrcalls.com/custom-calls.html