Liie Cajun said, it'll be an old mature cow in the lead of the herd usually, with the mature bull bringing up the rear. All the bulls will bugle about the same amount it seems like to me. When the heat of the rut is on, they can all be very vocal. About the only thing that really will make elk change elevation is heavy snow. But ya gotta remember, if they are spooked or feel heavy hunting pressure, it's nothing for them to move a mile, and that could include going up 1000' plus feet to go over a ridge/mtn.