One after another, young and curious Rocky Mountain elk use their tongues and noses to investigate WPS cameras on a windy day in late May in Rocky Mountain National Park, northern Colorado. Once their curiosity is satisfied, they continue to graze past our cameras, fattening themselves on new spring grasses. Elk herds vary in size from small to large groups like this one—in some cases swelling to hundreds of individuals. Their range extends across 415 square miles of park lands into adjacent front range terrain.
Antlers Signal Health
Elk need to eat three pounds of grass, forbs (flowering plants), and shrubs daily for every 100 pounds they weigh in order to be in optimal health. That’s a lot of grass! This is especially important for young males, called bulls, who need all the energy they can get from food to grow antlers, which start growing in April and reach full size in August. The bulls’ antlers are visible on our footage as fuzzy stubs. When grown, the antlers of these elk can outrival in size those of all six sub-species of elk in North America—weighing up to 40 pounds on mature bulls. Come rutting season in autumn, which peaks mid-September to mid-October, a bull’s antlers will be used to fight other males and attract females, called cows, to its harem. Each harem typically has up to six cows. The young bulls in our video, however, must wait until they reach sexual maturity before they can compete—typically from age two to four or five.
Strange Sounds in the Night
The telltale sound of rutting season is the bull’s bugling call to females, which they can also use to assert dominance over other males. The haunting cries, which are sometimes shrill and at other times low and growling, can carry for miles on the wind. Many tourists travel to Rocky Mountain National Park specifically to hear elks bugle in autumn. Their sounds are a seasonal signature of the park’s natural soundscape. The best times for visitors to hear the elk are at dawn and dusk.
Chronic Wasting Disease
Wildlife biologists are studying a degenerative disease that is afflicting some Rocky Mountain elk and also deer known as Chronic Wasting Disease. In animals with the condition, abnormal pathogenic agents called prions attack the central nervous system—altering behavior and bodily functions, and ultimately “wasting” the brain, resulting in death. There is no known cure, and the origins are also unknown. Researchers are monitoring elk and deer populations to assess if and how the disease might be impacting their numbers. Many of the collared elk and deer in the park are part of this study. The collars transmit data from 5 up to 10 years about their migration, survival, disease, and habitat use.
Foraging herbivores such as elk help manage vegetation in ecosystems. There is a sweet spot for balance. For example, too much grazing can reduce plants that provide necessary ground cover for other animals. Under grazing could cause noxious plants and other vegetation to grow unchecked. Carnivores like mountain lions and wolves contribute to the balance by controlling elk numbers.
Julie West, WPS Communications Specialist