One thing I like about animals is that they have habits. If you hang around them long enough you can see patterns. “Thumper” likes to perch on top of this log and thump away! Grouse move around in their territory like a trapper on a trap line. They beat their wings against their chest creating a loud thrumming sound. (Unfortunately the trail camera does not have sound.) Once you’ve heard the it, you’ll never forget it.
He’s basically telling other males to stay away and any females that he’s there.