I have a Merriam's tom done "hanging dead". I brought a century old wooden fence post with some rusty barbed wire on it outta my woods. The bird is mounted with a rawhide thing wrapped around his legs and stuck through a crack on the top of the post. The post will free-stand on its base OR hang on a wall with a bracket.
Just be careful that your taxidermist knows what a hanging dead bird looks like. I've seen too many mounts where the dead bird is all spread out in display........defying muscle memory and gravity.