USGS Chronic Wasting Disease Research at the National Elk Refuge
National Elk Refuge looking towards Sheep Mountain
Over the past 20 years, chronic wasting disease (CWD) in Wyoming has been spreading slowly outward from the southeastern corner of the state into the Greater Yellowstone Area and Wyoming's elk feed grounds. CWD detections have been getting closer to the National Elk Refuge, which provides supplemental feeding to approximately 8,000 elk and 500 bison each winter. NOROCK scientists have been providing the science and tools to help the National Elk Refuge make informed management decisions about the elk on their refuge in the context of CWD.
National Elk Refuge and the Jackson Elk Herd
The National Elk Refuge (NER) is managed by the U.S. Fish and Wildlife (FWS) and located next to Grand Teton National Park (National Park Service), the Gros Ventre Range of Bridger-Teton National Forest (U.S. Forest Service), and the town of Jackson, Wyoming. This region is home to the Jackson elk herd (Jackson herd), the largest elk herd in North America and popular attraction at the NER. The Jackson herd summers in Teton and Yellowstone National Parks and Bridger-Teton National Forest. They migrate to lower elevations and many in the herd congregate at the NER in winter, where the FWS provides them supplemental feed. This management strategy results in potential tradeoffs:
- Supplemental feeding aggregates elk in high densities that may increase transmission of disease, like CWD
- Reduce winter starvation of elk
- Limit elk movement on the landscape, thus reducing wildlife-human conflicts such as:
- transmission of disease, like brucellosis
- limiting competition between elk and cattle for winter grazing
Chronic Wasting Disease
CWD is a100% fatal neurological disease with no effective cure or vaccine affecting members of the deer family, which include deer, elk, and moose in the U.S. The disease has been detected in 36 U.S. states (as of April 2025), including Wyoming. CWD detections have been found close to the NER, for example:
- in 2018 a CWD-positive mule deer was detected in Grand Teton National Park
- in 2020 a CWD-positive elk was detected in Grand Teton National Park
- in the winter of 2024-2025, CWD-positive elk were detected in several Wyoming state feedgrounds near the NER
The spread of CWD in the U.S., including its proximity to the NER, and the Jackson herd moving through land holdings managed by a diverse array of land managers has made NOROCK science increasingly valuable in providing wildlife managers information and tools on:
- How to assess CWD transmission risk due to elk aggregation
- Migration-CWD dynamics
- Management alternatives to supplemental feeding at the NER while considering the effects of CWD
NOROCK CWD Projects to Assist the National Elk Refuge
1) Predicting the effects of supplemental feeding and chronic wasting disease in Greater Yellowstone Ecosystem elk
The NER and its partners are assessing the continued winter feeding of the approximately 8,000 elk and 500 bison to inform a National Environmental Policy Act environmental impact statement associated with developing the next Bison and Elk Management Plan for the refuge. Using a structured decision-making process, USGS scientists worked with the FWS to identify key FWY objective and potential management alternatives to be evaluated and the results were published in a USGS report. The management alternatives evaluated in the report were:
- Continue supplement feeding of bison and elk on the NER
- Stop supplemental feeding on the NER
- Stop feeding after CWD on the NER reaches a 3% prevalence threshold
- Reduce and then stop feeding
- Increase harvest of elk to reduce their population, then stop feeding
FWS and collaborating agencies are using the results of the USGS report to further tailor their management alternatives considered in the next Bison and Elk Management Plan. Current information on the Elk and Bison Management Plan can be found here: https://www.fws.gov/NER-BEMP
Contacts: Paul Cross and Jonathan Cook, USGS
2) Migration and CWD
Increasing hunter harvest in CWD-affected regions is one of the main tools managers use when trying to limit CWD spread and growth. Yet, hunting can be very limited in suburban areas. As a result, suburban deer and elk densities can be high which leads to increased vehicle collisions, other forms of private property damage, higher disease risk, and works against the preservation of long-distance migrations.
Previous work showed that some elk are more easily food-conditioned and less human-averse. Those same elk were more likely to abandon long-distance migration. The proportion of long-distance migrants in the Jackson elk herd has declined over time despite well-conserved movement corridors connecting the National Elk Refuge with Grand Teton and Yellowstone National Parks. We hope to understand how the use of human-derived food sources in the suburbs surrounding Jackson, Wyoming relates to migration behavior and use of the Refuge in the Jackson elk herd. We are partnering with the U.S. Fish and Wildlife Service, National Park Service, and Wyoming Game & Fish Department to identify patterns that can inform management actions tailored to reducing CWD spread while preserving long-distance migration.
Contacts: Gavin Cotterill, USGS; Tabitha Graves, USGS; Paul Cross, USGS
3) Estimating the effects of artificial feeding at the National Elk Refuge on elk contact rates
In November 2018 chronic wasting disease (CWD) was detected for the first time in Teton County, Wyoming, in the heart of the globally-significant Greater Yellowstone Ecosystem (GYE). The detection occurred in a mule deer in Grand Teton National Park (GRTE) near the northern boundary of the National Elk Refuge (NER). Elk that winter on the NER are managed under the USFWS Bison and Elk Management Plan, in collaboration with the Wyoming Game & Fish Department (WYGFD). NER elk densities greatly exceed levels predicted to result in rapid population declines with the introduction of CWD. NER management options that influence animal aggregation and distribution include feeding and hunting. We are quantifying elk contact patterns on the NER and the role of supplemental feeding in modifying potential CWD transmission. We are also developing methods to more cost-effectively estimate elk densities using tools including satellite imagery and unmanned aerial systems and to evaluate the success of adaptive management in changing densities and degree of concentrations of elk.
For more information, click here.
Contacts: Tabitha Graves, USGS; Eric Cole, USFWS; Will Janousek, USGS
USGS Chronic Wasting Disease Research at NOROCK
Developing Tools to Evaluate Chronic Wasting Disease Transmission Risk
Over the past 20 years, chronic wasting disease (CWD) in Wyoming has been spreading slowly outward from the southeastern corner of the state into the Greater Yellowstone Area and Wyoming's elk feed grounds. CWD detections have been getting closer to the National Elk Refuge, which provides supplemental feeding to approximately 8,000 elk and 500 bison each winter. NOROCK scientists have been providing the science and tools to help the National Elk Refuge make informed management decisions about the elk on their refuge in the context of CWD.
National Elk Refuge and the Jackson Elk Herd
The National Elk Refuge (NER) is managed by the U.S. Fish and Wildlife (FWS) and located next to Grand Teton National Park (National Park Service), the Gros Ventre Range of Bridger-Teton National Forest (U.S. Forest Service), and the town of Jackson, Wyoming. This region is home to the Jackson elk herd (Jackson herd), the largest elk herd in North America and popular attraction at the NER. The Jackson herd summers in Teton and Yellowstone National Parks and Bridger-Teton National Forest. They migrate to lower elevations and many in the herd congregate at the NER in winter, where the FWS provides them supplemental feed. This management strategy results in potential tradeoffs:
- Supplemental feeding aggregates elk in high densities that may increase transmission of disease, like CWD
- Reduce winter starvation of elk
- Limit elk movement on the landscape, thus reducing wildlife-human conflicts such as:
- transmission of disease, like brucellosis
- limiting competition between elk and cattle for winter grazing
Chronic Wasting Disease
CWD is a100% fatal neurological disease with no effective cure or vaccine affecting members of the deer family, which include deer, elk, and moose in the U.S. The disease has been detected in 36 U.S. states (as of April 2025), including Wyoming. CWD detections have been found close to the NER, for example:
- in 2018 a CWD-positive mule deer was detected in Grand Teton National Park
- in 2020 a CWD-positive elk was detected in Grand Teton National Park
- in the winter of 2024-2025, CWD-positive elk were detected in several Wyoming state feedgrounds near the NER
The spread of CWD in the U.S., including its proximity to the NER, and the Jackson herd moving through land holdings managed by a diverse array of land managers has made NOROCK science increasingly valuable in providing wildlife managers information and tools on:
- How to assess CWD transmission risk due to elk aggregation
- Migration-CWD dynamics
- Management alternatives to supplemental feeding at the NER while considering the effects of CWD
NOROCK CWD Projects to Assist the National Elk Refuge
1) Predicting the effects of supplemental feeding and chronic wasting disease in Greater Yellowstone Ecosystem elk
The NER and its partners are assessing the continued winter feeding of the approximately 8,000 elk and 500 bison to inform a National Environmental Policy Act environmental impact statement associated with developing the next Bison and Elk Management Plan for the refuge. Using a structured decision-making process, USGS scientists worked with the FWS to identify key FWY objective and potential management alternatives to be evaluated and the results were published in a USGS report. The management alternatives evaluated in the report were:
- Continue supplement feeding of bison and elk on the NER
- Stop supplemental feeding on the NER
- Stop feeding after CWD on the NER reaches a 3% prevalence threshold
- Reduce and then stop feeding
- Increase harvest of elk to reduce their population, then stop feeding
FWS and collaborating agencies are using the results of the USGS report to further tailor their management alternatives considered in the next Bison and Elk Management Plan. Current information on the Elk and Bison Management Plan can be found here: https://www.fws.gov/NER-BEMP
Contacts: Paul Cross and Jonathan Cook, USGS
2) Migration and CWD
Increasing hunter harvest in CWD-affected regions is one of the main tools managers use when trying to limit CWD spread and growth. Yet, hunting can be very limited in suburban areas. As a result, suburban deer and elk densities can be high which leads to increased vehicle collisions, other forms of private property damage, higher disease risk, and works against the preservation of long-distance migrations.
Previous work showed that some elk are more easily food-conditioned and less human-averse. Those same elk were more likely to abandon long-distance migration. The proportion of long-distance migrants in the Jackson elk herd has declined over time despite well-conserved movement corridors connecting the National Elk Refuge with Grand Teton and Yellowstone National Parks. We hope to understand how the use of human-derived food sources in the suburbs surrounding Jackson, Wyoming relates to migration behavior and use of the Refuge in the Jackson elk herd. We are partnering with the U.S. Fish and Wildlife Service, National Park Service, and Wyoming Game & Fish Department to identify patterns that can inform management actions tailored to reducing CWD spread while preserving long-distance migration.
Contacts: Gavin Cotterill, USGS; Tabitha Graves, USGS; Paul Cross, USGS
3) Estimating the effects of artificial feeding at the National Elk Refuge on elk contact rates
In November 2018 chronic wasting disease (CWD) was detected for the first time in Teton County, Wyoming, in the heart of the globally-significant Greater Yellowstone Ecosystem (GYE). The detection occurred in a mule deer in Grand Teton National Park (GRTE) near the northern boundary of the National Elk Refuge (NER). Elk that winter on the NER are managed under the USFWS Bison and Elk Management Plan, in collaboration with the Wyoming Game & Fish Department (WYGFD). NER elk densities greatly exceed levels predicted to result in rapid population declines with the introduction of CWD. NER management options that influence animal aggregation and distribution include feeding and hunting. We are quantifying elk contact patterns on the NER and the role of supplemental feeding in modifying potential CWD transmission. We are also developing methods to more cost-effectively estimate elk densities using tools including satellite imagery and unmanned aerial systems and to evaluate the success of adaptive management in changing densities and degree of concentrations of elk.
For more information, click here.
Contacts: Tabitha Graves, USGS; Eric Cole, USFWS; Will Janousek, USGS