I don' t know about Idaho, but in NH where I hunt I call Bull moose in every year while deer hunting between Sept 15th and October 1st. I have had luck calling them in using an immature buck grunt, but calling a little longer than you would for deer. If you get a bull interested you' ll hear them from pretty far off with their deep rythmic grunt/coughs when they come in. I have also had luck using rattling to bring in Bulls. The dominant Bull in an area usually comes in ALL fired up .. so be careful .. if you see what a rutting moose does to a 15' tree in a few swipes of his antlers .. you' ll be impressed.

I called in my first moose by accident archery deer hunting. Since drawing a moose tag in NH is almost impossible, I enjoy trying to call them in later in the morning when the deer hunting slows down, they are really cool animals to watch.