The National Elk Refuge (NER) is a federally managed sanctuary established in 1912 in Jackson Hole, Wyoming. This nearly 25,000-acre tract of land preserves the winter habitat for a significant portion of the Jackson Elk Herd. As an integral component of the Greater Yellowstone Ecosystem, the refuge provides a mild, low-elevation winter range for thousands of elk migrating from surrounding high-country areas, ensuring the long-term survival and health of this migratory herd.
The Annual Census: Current and Historical Numbers
The number of elk wintering on the National Elk Refuge fluctuates annually, typically ranging between 5,000 and 7,500 animals during the coldest months. The total Jackson Elk Herd, which includes animals outside the refuge, is estimated to be between 9,000 and 13,000. This count is usually taken in late winter, often around February, when the herd is most consolidated on the refuge.
Wildlife managers from the U.S. Fish and Wildlife Service (USFWS) and the Wyoming Game and Fish Department (WGFD) collaborate to set a population objective for the entire Jackson Elk Herd. Management efforts have aimed to reduce the overall population toward a target number, sometimes as low as 5,000, to balance the needs of the herd with the habitat capacity.
Historical counts highlight the dynamic nature of the population; early censuses in the 1910s accounted for approximately 20,000 animals in the Jackson Hole area. Current population objectives reflect a long-term strategy to ensure the health of the herd and the surrounding ecosystem.
Seasonal Movement and Herd Dynamics
The fluctuation in elk numbers on the refuge is directly tied to the annual migratory cycle of the Jackson Elk Herd. As spring arrives, the herd disperses from the refuge, following the receding snow line into their summer ranges. These feeding grounds extend northward into Grand Teton National Park, the Teton Wilderness, and the southern reaches of Yellowstone National Park.
The onset and severity of winter weather are the primary drivers for when and how many elk arrive. Early, heavy snowfalls push elk off their high-elevation summer ranges sooner, resulting in a larger concentration on the refuge. Conversely, mild winters allow elk to remain dispersed across forest lands for longer periods, sustaining themselves on natural forage outside the refuge boundary. A low count on the refuge often indicates a less severe winter that allows for better distribution of the animals, rather than a declining herd.
The Management Strategy for Herd Health
The management of the elk population involves human intervention to maintain herd health and ecological balance. A central and historically controversial practice is supplemental winter feeding, which began in the early 1900s to prevent mass starvation after settlers blocked traditional migration routes. This involves distributing alfalfa pellets or hay to thousands of elk during the harshest periods of winter.
While feeding ensures survival, it creates unnaturally dense congregations of animals, heightening the risk of disease transmission, particularly Chronic Wasting Disease (CWD) and Brucellosis. Managers mitigate this risk by using a feeding trigger point, initiating supplemental feed when available natural forage drops below a specific threshold. The USFWS and WGFD collaborate on plans to reduce the reliance on feeding.
Population control measures, including regulated hunting on the refuge and surrounding areas, are used to meet established population objectives. The goal is to keep the herd size at a level that prevents overgrazing of the habitat and minimizes the risk of widespread disease outbreaks. Management proposals have modeled scenarios where feeding would cease if CWD prevalence reaches a predetermined level, in an effort to curb the disease’s spread.
The ongoing challenge is balancing the historical commitment to protecting the herd with the modern ecological imperative of managing disease and habitat sustainability. By setting population objectives and adjusting feeding based on forage conditions and disease risk, the agencies attempt to promote a more self-sustaining and healthy herd. This adaptive management approach is constantly being refined in response to new scientific modeling and the growing threat of CWD.
Counting Methods: How the Population is Tracked
To accurately track the herd size and movement, the refuge employs a combination of scientific counting methods.
Aerial Surveys
The most comprehensive annual count is the aerial survey, conducted from fixed-wing aircraft or helicopters during mid-winter. This method captures a snapshot of the population when the elk are most concentrated and visible against the snow.
Ground Counts
Refuge biologists also conduct weekly ground counts within a standardized survey area, typically covering the southern portion of the refuge. These observations help monitor the influx and outflow of animals throughout the winter season and provide timely data on herd distribution.
Telemetry Technology
Researchers utilize advanced telemetry technology to monitor the herd’s dynamics. Specific elk are fitted with GPS or radio collars, which transmit location data multiple times a day. This technology helps biologists track migration routes and estimate the overall population size and distribution across the Jackson Elk Herd unit.