Each year, as the days of summer dwindle and the colors of fall begin to emerge in the Pacific Northwest, an otherworldly sound during Roosevelt elk's mating season fills the air in the foothills of Mount Rainier at Northwest Trek Wildlife Park, about an hour from Seattle. | Reuters

Roosevelt bull elk bugling during the rut, or breeding season. This incredible sound is made to show off to other bulls and the females. | Northwest Trek Wildlife Park

Bull elk bugling during the rut in the Canadian Rockies #elk #deer #rut #elkbugle | Harry Collins Photography

174K views · 2.3K reactions | Early elk rut with a nice bugle!! | Estes Park News, Inc. | Facebook

Bugle Boy! Sound up to listen to the current lead bull let out a big bugle today during elk rut (breeding season). | Northwest Trek Wildlife Park

During the elk mating season (rut), which generally happens from now through mid-October, bulls bugle to announce their availability and fitness to females and to warn and challenge other bulls. While this iconic song is a beautiful backdrop to fall in Yellowstone, remember that bull elk can be extremely dangerous during this time. Always keep at least 25 yards from elk. More elk bugling videos are available on our website: https://www.nps.gov/yell/learn/photosmultimedia/vl_elkbugling.htm. Note: