My first experience trying a moose cal went like this.
I had been afraid to try. Always thought my attepts sounded stupid. I made several birch bark calls, and practiced, but never used them hunting.
Then, one day, near last light, I figured what the hell, i cupped my hands, and made my best attempt at a grunt.
The bush fairly exploded about fifty yards up the bank, and a yearling for which i had no tag, came charging up the swamp right at me.
He was in spear chucking distance, and I was looking for a tree to climb (none), when I moved out where he could see me, waved my arm, and said hello to him. He stopped, maybe 20 feet away, and looked me over. Then he turned and calmly walked out across the swamp. I stopped him twice more with grunts from my cupped hands!
I've been calling ever since.