They do work very good. They key is to put a lot of emotion in your calling. If you've ever heard a fawn screaming you wouldn't forget it. It sounds just like a small child srceaming bloody murder. I was roofing my brother's house and heard what I thought was one of my kids at the pond screaming so I rushed over there and found that my dogs had a fawn out in the middle of the pond. I'll never forget the way it screamed(I swam out there and rescued the fawn and took it to where I last saw the mother and she took it back). Anyway, make your calls loud and change tones.