Bugle. During the mating season (or Rut), the male elk, the bull, bugles. This is attract females but more importantly to keep other bulls away from his herd of cows. This was taken in Rocky Mountain National Park - RMNP before the sunrise. Shortly before this was taken, this Bull went after another Bull and sparred with him.
RutRMNPRocky Mountain National ParkBull ElkBugleSlideshowSeptember2009