you will hear various things but if you know the birds are there I would tend to stay back listen for them to fly up to roost & then glass the fields to see when they are using them. If your lucky you can find where they sleep & where they strut and eat. If you find that you can kill the birds even if they are not vocal.

It is also well worth your effort to walk any roads that you can & see if you can find tracks droppings & dropped feathers. Turkeys tend to walk roads a lot more than other creatures. Good Luck!