Most folks have said hardwoods.. (I agree) I usually don't give advice on something I haven't tried myself... I've been wanting to give this a try as I've heard several folks swear by it. If you'll take to coins and scrape the edges together rapidly it sounds like a squirrel cutting an acorn... folks on other forums I'm on swear they'll come running and almost sit in your lap... wish I could say I've given it a try but I rarely sway from coyote hunting... let me know if it works for you!