East Walker Mule Deer

East Walker mule deer are mostly traditional migrants that migrate between distinct seasonal ranges in central California near the Nevada border. Their winter range comprises Pinus spp. (pinyon)-Juniperus spp. (juniper) and spans Wovoka Wilderness in Nevada and an area east of State Route 338 in Nevada and State Route 182 in California. In 2019, the herd contained 1,279 mule deer (Tom Stephenson, California Department of Fish and Wildlife, written commun., 2025). In the spring, individuals move west into California using several corridors; however, a concentrated migration corridor parallels the East Walker River, crossing State Route 182 and into the Sweetwater Mountains to the north of Bridgeport Reservoir, ending in the Sierra Nevada (fig. 3). Most deer do not cross into Yosemite National Park, instead summering in the Toiyabe National Forest (part of the Humboldt-Toiyabe National Forest) or Bureau of Land Management (BLM) lands. Migration corridors varied from short (3.96 miles [mi]; 6.38 kilometers [km]) to long (41.54 mi [66.85 km]) distances and migration start dates were variable within and among years.

West Walker Mule Deer

West Walker mule deer are mostly traditional migrants in east-central California, near the Nevada border. Their winter range spans Antelope Valley in California and Nevada and stretches across State Route 395 into Slinkard Valley and Little Antelope Valley near Walker, California. In 2019, the herd contained an estimated 3,589 mule deer (Tom Stephenson, California Department of Fish and Wildlife, written commun., 2025). In the spring, individuals move south and west into higher elevations in California using several corridors; however, a concentrated migration corridor parallels the West Walker River, straddling State Routes 395 and 108 to the west of the Sweetwater Mountains and ending in the Sierra Nevada (fig. 4). Most deer do not cross into Yosemite National Park, instead summering in montane forests of Stanislaus and Toiyabe National Forests (part of the Humboldt-Toiyabe National Forest). Some mule deer are multirange migrants, moving among two or more distinct ranges in a single season.

North Park Mule Deer

The North Park mule deer herd (Data Analysis Unit [DAU] D3) inhabits North Park, an intermountain basin on the east side of the Continental Divide in Jackson County, Colorado (fig. 5). Elevations within the DAU range from approximately 7,800 to 13,000 feet (ft; 2,377 to 3962 meters [m]). North Park is bound to the north by the Wyoming border, to the east by the Medicine Bow Mountains and Never Summer Mountains, to the south by the Rabbit Ears Range, and to the west by the Park Range. North Park serves as the headwaters of the North Platte River and contains many drainages, including the Illinois River, Michigan River, Canadian River, and the North Fork of the North Platte River. The North Park basin spans 1.04 million acres (420,873 ha) and features diverse landownership, including 12 percent State, 36 percent private, and 52 percent Federal land (BLM, U.S. Department of Agriculture Forest Service [FS], and U.S. Fish and Wildlife Service).

During the summer, North Park mule deer are dispersed across the entire DAU; higher deer densities are in forested and alpine habitats more than 8,500 ft (2,591 m). Population estimates have historically fluctuated, peaking at 10,000–12,000 deer in the 1950s (Don Gore, Colorado Division of Wildlife, written commun., 2025), though more recent estimates indicate approximately 4,500–6,000 deer (the 2023 posthunt estimate was 5,400 deer; Eric VanNatta, Colorado Parks and Wildlife [CPW], written commun., 2025). Historically, North Park supported a large wintering deer population within the DAU. However, in the early 2000s, CPW staff observed a shift in wintering deer patterns; most deer now migrate from North Park to adjacent winter ranges to the north, east, and south of the DAU. Despite only moderate land-use changes, including the conversion of some Artemisia spp. (sagebrush) habitat to grassland for livestock grazing, North Park still retains quality mule deer winter range, although few, if any, deer now use it. CPW staff hypothesize this shift in winter deer distribution may be a result of past management decisions implemented during the mid-1900s, when a combination of relatively liberal hunting quotas and late-season hunting permitted years of heavy, targeted harvest of deer on local winter range. Because of this management regime, a smaller migratory subset of deer that were less affected by hunter harvest may have experienced higher survival and may have led to migratory behavior becoming more dominant.

The predominance of this migratory behavior poses challenges for managing a stable population. For example, CPW classification survey flights, done annually in late December or early January, coincide with winter conditions that drive deer, elk, and Alces alces (moose) into areas with greater sightability. Surveys from the 1960s to 1970s reported 2,000–3,000 mule deer per year. However, an average of only 250 deer per year have been counted during the past decade (CPW, 2023), likely because most mule deer have already left North Park or are near staging areas along suspected migration routes during the typical survey period. These small sample sizes complicate population modeling, limiting CPW’s ability to accurately estimate population size and detect subtle demographic changes. This challenge has spurred recent research, funded by Secretarial Order 3362, into understanding North Park mule deer migration characteristics.

San Juan Basin Mule Deer

The San Juan Basin mule deer herd (DAU D30) inhabits a 2,800-square mile (mi²; 7,252-square kilometer [km²]) area in the southwest corner of Colorado (fig. 6). It is bounded to the north and east by the Continental Divide, to the south by the Colorado and New Mexico border, and to the west by the Animas River. Elevations range from 5,000 ft (1,524 m) to more than 14,000 ft (4,267 m). The DAU encompasses Durango, Bayfield, Ignacio, and Pagosa Springs, Colorado, and landownership is a mix of 30 percent private, 12 percent Southern Ute Indian Tribe of the Southern Ute Reservation, Colorado (hereafter Southern Ute Indian Tribe), 2 percent BLM lands, and 56 percent FS lands.

The San Juan Basin mule deer herd includes migratory and nonmigratory individuals. Deer generally summer at higher elevations in the northern and eastern part of the DAU and winter at lower elevations to the south. The timing of deer migration is consistent annually; peak spring migration occurs approximately during the second week of May, and the peak fall migration occurs approximately during the third week of October. In the fall, males generally migrate 1–2 weeks later than females. Part of the deer herd’s migration corridor and winter range extends onto Southern Ute Indian Tribal lands and into New Mexico. Resident deer remain year round at the lower elevations that are often associated with agriculture fields.

The main threats to the San Juan Basin mule deer herd include human development and associated infrastructure. Energy and recreational development occur on a large part of important habitat for the San Juan mule deer herd and jeopardize their available resources. Development concerns are a region-wide issue, but they pose a greater problem near Durango, Bayfield, and Pagosa Springs, Colorado.

Additionally, the San Juan mule deer herd inhabits an area with some of the highest recorded wildlife-vehicle collisions (WVCs) in the State. Several highways bisect mule deer migration corridors and winter range, including U.S. Highways 160, 84, and 550, and Colorado State Highways 172, 151, 240, and 501. GPS-collar data from female mule deer have helped identify locations where mule deer cross roadways. These data, along with WVC data, have been instrumental in prioritizing where to build wildlife-crossing structures to ease mule deer movement across busy roads. In 2022, the Colorado Department of Transportation (CDOT), the Southern Ute Indian Tribe, CPW, and other partners helped to fund the construction of a wildlife overpass and underpass on a 1.9-mi (3.1-km) section of U.S. Highway 160 near Chimney Rock and the intersection of Colorado State Highway 151. In 2023, a network of camera traps was established to determine the effectiveness of wildlife-crossing structure installations to reduce WVCs and maintain wildlife movement permeability. Within the first 8 months of monitoring (October 2023 through June 2024), mule deer, elk, Ursus americanus (black bears), Puma concolor (mountain lions), and many smaller mammal species successfully used the crossing structures (Cramer, 2024). The CDOT has plans for additional crossing structures as funding becomes available.

Blackrock Canyon Mule Deer

The Blackrock Canyon mule deer herd winters near Pocatello, Idaho. During very severe winters, most deer live within 0.5 mi (1 km) of the Interstate 15 corridor from Inkom, Idaho, to the southeast extent of the Pocatello city limits (fig. 7). During milder winters, deer shift southeast of Pocatello and use a broader winter range covering approximately 27 mi² (70 km²). Recent aerial abundance surveys indicated that 1,500–2,500 mule deer winter to the southeast of Pocatello. The Interstate 15 corridor is fenced with wildlife-exclusionary fencing from Inkom to Pocatello, and very little movement currently (2025) occurs between the Blackrock Canyon mule deer herd and deer south of the highway. Before 2020, the Blackrock Canyon mule deer winter range was considered part of the Bannock mule deer herd to the southwest. However, as more GPS-collar data were collected, it became clear that the winter range of this herd had little connectivity to those southwestern areas and, instead, was integrally connected to summer ranges to the north and east. Blackrock Canyon mule deer travel to the east–northeast through the Fort Hall Reservation to the Portneuf Range, Chesterfield Range, the foothills of the Grays Range, and near the Blackfoot Reservoir. In the winter range, wildfire has degraded the lowest-elevation areas, and nonnative, invasive annual grasses have flourished. Fencing, WVCs, urban sprawl, and connectivity are also concerns for this herd. In the summer range, human-caused resource extraction and Populus tremuloides (quaking aspen) stand invasion by Pseudotsuga menziesii (Douglas fir) continue to challenge and degrade nutrient-rich summer habitats.

Hells Canyon Mule Deer

The Hells Canyon mule deer herd consists of 3,000–5,000 deer that winter primarily in sagebrush-steppe habitat adjacent to the Snake River and near the Brownlee and Oxbow dams (fig. 8). The area is dominated by steep canyons with grasslands and sagebrush-steppe habitat at lower elevations and on south-facing slopes and pine at higher elevations. Most of this herd summers at high elevations in the management unit, to the northwest of Cambridge and west of Council, Idaho. However, a large part of this herd winters farther east, south of New Meadows, Idaho, where it overlaps with the Weiser mule deer herd and migrants from areas around Riggins, Idaho. Additionally, several Hells Canyon mule deer cross the Snake River between Oregon and Idaho during their seasonal migrations. Hells Canyon mule deer face multiple challenges along their migration routes, including crossing State Highway 95, Idaho’s primary north–south highway, increased energy and mining development, and navigating a matrix of private and public lands. Frequent, large wildfires degrade winter range quality and promote the establishment of invasive annual grasses on winter and summer ranges.

Canyon de Chelly Mule Deer

The Canyon de Chelly mule deer herd is one of several herds that winter in the foothills of the Chuska Mountains, an 80-mile (129-km) long range within the southeastern Colorado Plateau in Navajo Nation, Arizona, New Mexico, & Utah (hereafter Navajo Nation). Initially included in Kauffman and others (2022a), this herd has been updated for this report with data from additional years. The winter ranges and migration corridors of the Canyon de Chelly herd are just 7 mi (11 km) south of the Ram Pasture herd (refer to the “Ram Pasture Mule Deer” section of this report) but are separated geographically by Canyon del Muerto and Black Rock Canyon (fig. 9). These canyons are part of the larger Canyon de Chelly National Monument. Unlike other federally managed parks, the monument is comanaged with a Native American Tribe, whereas all parklands remain Navajo Nation Tribal trust land (National Park Service, 2025). Members of the Navajo Nation continue to reside in and around the canyons, maintaining livestock and cultivating crops. Although the canyon has accessible routes and perennial streams, GPS-collared mule deer primarily winter on the canyon mesas. Windmills installed by the Navajo Nation Department of Water Resources for livestock also provide a critical water source for mule deer in winter. During spring and fall migrations, the Canyon de Chelly herd crosses Indian Route 12, a heavily traveled rural highway along the Arizona and New Mexico border. The primary challenges the herd faces during migration include vehicular collisions, urban development, and overgrazing by feral horses and unregulated livestock.

Ram Pasture Mule Deer

The Ram Pasture mule deer herd is one of several herds that winter in the foothills of the 80-mi (129-km) long Chuska Mountains in Navajo Nation (fig. 10). This herd was originally included in Kauffman and others (2022a) and has been updated for this report to include new data from additional years and mule deer (12 new adults; Kauffman and others, 2022a). These mule deer winter in pinyon-juniper and sagebrush foothills; migrate to the east to higher elevations in the spring; and summer in habitats comprised of mixed conifer, aspen, high alpine meadows, and Pinus ponderosa (ponderosa pine). Winter and summer ranges remain entirely within Tribal trust lands managed by the Navajo Nation Department of Fish and Wildlife. Similar to the Canyon de Chelly mule deer herd (refer to the “Canyon de Chelly Mule Deer” section of this report), every spring and fall, the Ram Pasture herd must cross Indian Route 12, a busy rural highway along the Arizona and New Mexico border. During migration seasons, WVCs are a continuous problem in these areas. In 2023, aerial surveys estimated 1,030 mule deer as the minimum number of known alive deer throughout their winter ranges in the Chuska Mountains, which is a decline from the 2020 estimate of 1,583 mule deer (Kauffman and others, 2022a). The limiting factors for this herd include low-quality habitat caused by overgrazing and resource competition with feral horses and unregulated livestock (Davies and Boyd, 2019; Wallace and others, 2021). Furthermore, extended drought and habitat fragmentation driven by urban development have accelerated the decline of habitat suitability (Redsteer and others, 2018; Nania and others, 2014).

Washoe Mule Deer

The Washoe mule deer herd inhabits the northwest corner of Nevada, northeastern California, and southern Oregon (fig. 11). The Washoe mule deer herd spans seven of Nevada Department of Wildlife (NDOW)’s Hunt Units (011–015, 032–033) and consists of long-distance and short-distance migrants; some deer travel more than 62 mi (100 km), and other deer travel less than 0.5 mi (1 km) downslope to lower elevations during the winter. The Washoe mule deer herd comprises several subherds, including the Mosquito Mountain, Sheldon National Wildlife Refuge, Vya, Boulder Mountain, and Granite Peak mule deer. Over the past 10 years, the Washoe mule deer herd has declined drastically, largely because of the long-term effects of drought. Other threats this herd faces include fencing, habitat loss from wildfires, the conversion of shrublands to annual grasses, and competition with feral horses for forage and water. Several habitat projects have been initiated to help manage these mule deer subherds, including spring protection projects in Hunt Unit 013 near Findman Spring and Horse Canyon Spring, and in Hunt Unit 015 near Horse Corral and Byers Springs. Additionally, approximately 7.5 mi. (12 km) of fencing improvements have been made along the California border near Big Mud Lake and Fee Reservoir (NDOW, 2024).

Beaver Mule Deer

The Beaver mule deer herd inhabits the Beaver Wildlife Management Unit (WMU) in southern Utah and includes three mountain ranges: the Tushar Mountains in the east and the Mineral and Black Mountains in the west (fig. 12). The WMU encompasses more than 885,000 acres (358,147 ha) of mule deer range and has approximately 12,000 mule deer (Utah Division of Wildlife Resources [UDWR], 2020b). The area is mostly rural, and landownership consists mainly of BLM and FS lands (UDWR, 2020b). The Beaver mule deer herd is migratory; most deer summer in high elevations on the Tushar Mountains, but some use limited summer range on the Mineral and Black Mountains. Mule deer winter in the lower-elevation slopes of all three mountain ranges. Most mule deer habitat in this WMU is made up of pinyon-juniper woodland (38 percent) and sagebrush-steppe and shrublands (27 percent; Payne and others, 2023). However, widespread encroachment of pinyon and juniper into sagebrush shrublands has decreased available food sources for Beaver mule deer.

Other challenges this herd faces include drought conditions, which much of the Beaver WMU has experienced for 68 percent of the time since 1993 (Payne and others, 2023). Several major roads with high traffic densities pass through this WMU, resulting in concentrated WVCs along sections of Interstate 15, State Route 20, and State Route 21 (Payne and others, 2023). Several mitigation measures have been installed in these areas, including five wildlife crossings and mesh wire exclusionary fencing along Interstate 15 and Interstate 70, which have begun to reduce these WVC effects (Payne and others, 2023). The UDWR uses the GPS data of this herd to describe migration corridors and determine crucial habitats.

Chalk Creek Mule Deer

The Chalk Creek mule deer herd inhabits the Chalk Creek WMU in northern Utah, northeast of Salt Lake City, Utah, and abuts the Wyoming border (fig. 13). The WMU is bordered to the east by the Uinta Mountains and to the west by the Weber River and two State park reservoirs, Echo Reservoir and Rockport Lake. It encompasses 380,608 acres (154,027 ha) of mule deer range and has approximately 11,250 mule deer (UDWR, 2023b). Landownership is primarily private (88 percent summer range, 96 percent winter range), which makes management of critical mule deer habitat challenging for UDWR (UDWR, 2023b). The Chalk Creek mule deer herd is migratory; deer use high-elevation habitat on private and FS lands in the summer, and limited low-elevation habitats on mostly private lands in the winter. Habitat vegetation types in this WMU include sagebrush–grass, Quercus gambelii (oak brush), and juniper, and 43 percent of the WMU consists of shrubland cover (Payne and others, 2021).

Winter range is limited and threatened by development, agriculture, oil and gas infrastructure, juniper encroachment, and overuse by large elk herds (Payne and others, 2021; UDWR, 2023b). Additionally, Echo Reservoir and Rockport Lake hinder mule deer movement on the west side of the herd’s range. A high number of WVCs occur along Interstate 80 near the reservoirs, particularly along Echo Reservoir where a high use migration corridor intersects Interstate 80 (Payne and others, 2021). The UDWR works closely with the Utah Department of Transportation to prevent WVCs in this unit through fence installation, construction of wildlife escape ramps, and inclusion of wildlife underpasses (UDWR, 2023b). The UDWR uses the GPS data of this herd to describe migration corridors and identify crucial habitats.

La Sal Mule Deer

The La Sal mule deer herd inhabits the La Sal WMU in southeastern Utah, abutting the Colorado border (fig. 14). Southeastern Utah has varied geography, including a section of the Disappointment Valley, the Colorado River, La Sal Mountains, Arches National Park, and part of Uncompahgre National Forest in western Colorado. The elevation ranges from 4,000 ft (1,219 m) at the lowest point to 12,721 ft (3,877 m) at the highest point (Payne and others, 2019). It encompasses 507,156 acres (205,239 ha) of mule deer range, mostly on and around La Sal Mountains, and has approximately 5,100 mule deer (UDWR, 2020a). Land is primarily managed by the BLM in the winter range (73 percent) and FS in the summer range (57 percent). The annual range is made up of National Park Service lands (41 percent) and BLM lands (46 percent; UDWR, 2020a). The La Sal mule deer herd is migratory; animals use high-elevation slopes in La Sal Mountains in the summer and mesas at 8,000 ft (2,438 m) or lower in the winter, which are all on the east side of the WMU. About 60 percent of the unit comprises shrublands, including Coleogyne ramosissima (blackbrush), a key browse species for mule deer, but most of these areas are not considered mule deer habitat (Payne and others, 2019). The herd faces several challenges, including habitat quality and quantity, pinyon-juniper encroachment, and wildlife-unfriendly fences and crossings that reduce ranges (Payne and others, 2019). The La Sal WMU has the highest prevalence of chronic wasting disease (CWD) in the State; CWD increased in prevalence from 7.9 percent to 14.1 percent between 2015 and 2020 (UDWR, 2020a). The UDWR uses the GPS data of this herd to describe migration corridors, identify crucial habitats, and determine CWD transmission risk.

Oquirrh-Stansbury Mule Deer

The Oquirrh-Stansbury mule deer herd inhabits the Oquirrh-Stansbury WMU in north-central Utah, south of the Great Salt Lake (fig. 15). The WMU includes parts of Salt Lake City, Tooele, Grantsville, and Stockton, Utah, and two mountain ranges: the Stansbury Mountains to the west and the Oquirrh Mountains to the east. It encompasses 449,582 acres (181,939 ha) of mule deer range and has approximately 9,900 mule deer (UDWR, 2023a). Landownership is a mix of private (38.2 percent summer range, 38.6 percent winter range), BLM (27.3 percent summer range, 31.3 percent winter range), and FS (28.8 percent summer range, 7.2 percent winter range) lands (UDWR, 2023a). In the fall, deer migrate from high-elevation summer ranges to low-elevation winter ranges surrounding the Stansbury and Oquirrh Mountains. A small part of the winter habitat and migration corridors overlap with developed areas in the WMU. On the west side of the unit, habitat consists primarily of shrubland (36 percent) and a mix of mostly developed, agricultural, open water, and sparsely vegetated areas (24 percent; Payne and others, 2021). On the east side of the WMU, only 23 percent of the habitat is shrubland, and 57 percent is a mix of developed, agricultural, open water, and sparsely vegetated areas (Payne and others, 2021). The herd faces several challenges, including winter range habitat conditions and habitat degradation and loss due to housing development, mining, and pinyon-juniper encroachment on sagebrush rangelands (Payne and others, 2021). Additionally, deer fences and crossings may limit deer ranges, emphasizing the importance of agency collaborations to ensure habitat access for deer and human safety (Payne and others, 2021). The UDWR uses the GPS collar data of this population to monitor mule deer survival, describe migration corridors, and identify crucial habitats.

Uinta Mule Deer

Between 2021 and 2024, the Wyoming Cooperative Fish and Wildlife Research Unit at the University of Wyoming and the Wyoming Game and Fish Department (WGFD) conducted a GPS-collaring study to further understand the movement patterns and habitat use of mule deer near Evanston, Wyoming (fig. 16). To gain additional insight into the potential effects of U.S. Highway 189 and Interstate 80 on deer movements, wildlife cameras were used to monitor crossing structures along these highways. Almost 7,000 deer crossings were documented during the winter of 2021–22. New underpasses and a potential overpass to mitigate WVCs are planned for the section of U.S. Highway 189 north of its intersection with Interstate 80. The GPS-collar data collected from this study will likely be used to help the Wyoming Department of Transportation and other agency partners appropriately site these crossing structures to conserve mule deer migrations and reduce WVCs.

Most of the mule deer in the Uinta herd winter in the flats and hills to the north, east, and south of the intersection of U.S. Highway 189 and Interstate 80. Winter range is characterized by Juniperus osteosperma (Utah juniper) and sagebrush species, including Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) that occupies most upland sites, Artemisia tridentata ssp. tridentata (basin big sagebrush) in ephemeral drainages and terraces adjacent to riparian areas, Artemisia arbuscula ssp. longiloba (early sagebrush) in upland sites with clay soils, and Artemisia nova (black sagebrush) on shallow soil and gravelly sites. Migrations of these mule deer extend from their winter ranges north into the Wyoming Range, west into the foothills of northeastern Utah, and south into the foothills of the Uinta Mountains. During migration, mule deer must navigate linear barriers such as Interstate 80, U.S. Highway 189, and Wyoming State Highway 89, which can lead to WVCs. Mule deer summer ranges along the Bear River Divide, foothills of the Uinta Mountains, and lower elevations of the Wyoming Range comprise mixed mountain shrubs and aspen habitat. Mountain shrub species consist of Artemisia tridentata ssp. vaseyana (mountain big sagebrush), Purshia tridentata (antelope bitterbrush), Amelanchier alnifolia (western serviceberry), Cercocarpus montanus (true mountain mahogany), and Symphoricarpos albus (common snowberry). Healthy aspen understories include species such as Geranium viscosissimum (sticky geranium), Ligusticum porteri (Porter’s licorice-root), Elymus glaucus (blue wildrye), and Bromus marginatus (mountain brome). High-elevation summer ranges comprise conifer stands as well as tall forb and alpine meadow communities.

Upper Wind River Mule Deer

The Upper Wind River mule deer herd is a larger aggregate of the Dubois, Wind River, and Owl Creek herds, which were included in previous volumes of the report series (Kauffman and others, 2020a, 2022a). Upper Wind River deer migrate varying distances, ranging from 5 to 90 mi (8 to 144 km) between their winter and summer ranges. Short-distance migrations are largely elevational from winter ranges on the lowlands along the Wind River to summer ranges in the Wind River Range (fig. 17). Many deer migrate longer distances into the heart of the Greater Yellowstone Ecosystem, including Yellowstone and Grand Teton National Parks. Mule deer in this migration corridor winter on habitats in the upper Wind River valley under the jurisdiction and sovereignty of the Eastern Shoshone Tribe of the Wind River Reservation, Wyoming, and Northern Arapaho Tribe of the Wind River Reservation, Wyoming (hereafter Wind River Reservation) and surrounding State, Federal, and private lands. Winter ranges are a mix of shrubs, herbaceous grasslands, riparian habitats, and mixed vegetation types associated with agriculture. Summer ranges on the surrounding national forests and national parks are predominantly Pinus contorta (lodgepole pine) montane forests with smaller areas of open herbaceous sagebrush–grasslands, and subalpine forests and grasslands at higher elevations in the Teton Range.

Though the herd has declined, it is one of the few mule deer herds in the State that has not experienced a large decline in recent decades. This relative stability of the herd may be partly because the herd continues to use intact migration routes and winter ranges each year, as it has for generations. Winter ranges and the migrations of this herd often cross U.S. Highway 26/287, which is the highest priority area in Wyoming for reducing WVCs (Wyoming Wildlife and Roadways Initiative, 2019). Additionally, part of the larger herd moves through residential subdivisions near Dubois, Wyoming, including undeveloped private lands. Recognizing the value of this migration, regional partners have collaborated to collect GPS data and track the herd’s movements. In 2024, the WGFD identified the migration corridor as part of Governor Gordon’s Migration Corridor Executive Order 2020–1 (State of Wyoming, 2020). Although the Wind River Reservation provides critical winter, migratory, and stopover habitat, the WGFD’s identified corridor ends at the reservation boundary to respect the sovereignty of the Tribes. Volumes 1 and 2 of the report series (Kauffman and others, 2020a, 2022a) detail the full migration routes of the three separate herds, including the routes through the Wind River Reservation.

White Clouds Pronghorn

The White Clouds pronghorn herd winter range runs from Willow Creek Summit to Bradbury Flat and extends to the south to Spar Canyon. Pronghorn concentrate on both sides of U.S. Highway 93 between Willow Creek Summit and Bradbury Flat in winter (fig. 18). This area is mostly public land (BLM) with some private properties along U.S. Highways 93 and 75. The winter range comprises broad, flat sagebrush-steppe at lower elevations and rolling, sagebrush-covered hills from Bradbury Flat to Road Creek. Snow accumulation is light during most winters with occasional short periods of deeper snow, generally later in winter (late January–February). Pronghorn concentrations vary depending on snow depth and winter severity. White Clouds pronghorn have two main migration styles. Most pronghorn wintering here migrate to the west along a narrow corridor following the East Fork Salmon River, Germania Creek, and Pole Creek to the Sawtooth Valley south of Stanley, Idaho. Once in the Stanley Basin, an unknown number of individuals stay south of Stanley, whereas others continue northwest into Valley Creek and upper Marsh Creek. This migration is likely the highest elevation pronghorn migration in North America (8,480 ft [2,585 m]). The summer range in the Sawtooth Valley, Valley Creek, and Marsh Creek receives abundant precipitation and comprises meadows and sagebrush-steppe with high-quality forage. The other, much shorter, migration routes are either limited elevational migrations to the northeast to the Lost River Range or to the southwest to the Road and Herd Creeks area. Barriers to this migration include wildlife-unfriendly fencing along the route and a long stretch of heavily forested habitat that pronghorn pass through, which increases the risk of predation by mountain lions, black bears, Canis lupus (gray wolves), and Canis latrans (coyotes). The White Clouds pronghorn herd faces unique challenges throughout the year. On summer range, increased development in the Sawtooth Valley and a concurrent increase in fences impede movements and access to forage; on the eastern part of the migration route, an increase in nonnative annual grasses (Bromus tectorum [cheatgrass]) reduces forage quality; and on winter range, an increasing feral horse population competes for forage and water resources.

Central Washoe Pronghorn

Central Washoe pronghorn use a network of interconnected migration corridors and seasonal ranges (fig. 19). Pronghorn summering east of Long Valley migrate south to winter ranges on Mahogany Mountain and the Calico Hills, where they overlap with pronghorn that summer near The Buttes. Pronghorn summering by Cherry Mountain also use Mahogany Mountain and areas near Nevada Route 447 during winter; some pronghorn travel long distances to use both locations during the same season. One pronghorn dispersed from the Calico Hills to Melody Mountain in early 2020, overlapping with other wintering pronghorn that summer near Granite Range and Hog Ranch Mountain. Pronghorn wintering by Boulder Flat have summer ranges to the southwest of Long Valley and near Surprise Valley, California. Other pronghorn wintering north of Nevada Route 447 migrate south to summer near the Cottonwood Mountains in California, temporarily overlapping with pronghorn that winter near the Smoke Creek Desert, and use additional summer ranges surrounding Painters Flat, California. Habitat primarily consists of shrub-steppe intermixed with grassland. Big sagebrush and basin big sagebrush dominate low altitudes, transitioning to Wyoming big sagebrush, followed by A. arbuscula (low sagebrush) and mountain big sagebrush as elevation increases.

Challenges to this herd include invasive annual grasses and Juniperus occidentalis (western juniper) encroachment, potential competition with feral horses, unpermitted livestock grazing on some BLM allotments, and livestock fences that inhibit efficient movement. Several habitat improvement projects have been implemented in Central Washoe County, Nevada. The Horse Canyon Spring protection project installed pipe-rail fencing to protect more than 8.75 acres (3.54 ha) of degraded springs and the Cherry Spring protection project preserved 20 acres (8.09 ha) of riparian habitat along a prominent pronghorn migration route on private land (NDOW, 2024). Additionally, the NDOW cooperated with the Winnemucca BLM Field Office to treat approximately 7,755 acres (3,138 ha) of burned native rangeland from the 2020 Poodle fire using an aerial herbicide application to reduce annual grass invasion and promote native vegetation growth.

Paulina Pronghorn

Most of the Paulina pronghorn herd winter either near U.S. Highway 20 or Browns Valley; additional winter ranges are near Christmas Lake Valley and Alfalfa, Oregon (fig. 20). During spring, pronghorn use a complex network of migration corridors to reach summer ranges near West Butte, Mahogany Butte, Trail Butte, Bronco Butte, Stookey Flat, and the base of the Maury Mountains. The seasonal ranges of different pronghorn frequently overlapped, often with the same area used as either summer or winter range, depending on the individual. One pronghorn dispersed north almost 60 mi (97 km) to new seasonal ranges near Waterman Flat during the spring of 2018, crossing the Ochoco Mountains and U.S. Highway 26. In 2019, another pronghorn traveled south from winter range in Browns Valley until finally turning back at Oregon Route 140 and crossing U.S. Highway 395 twice in a 76-mi (122-km) round-trip movement.

Summer and winter ranges were dominated by shrubland with common species, including low sagebrush, big sagebrush, mountain big sagebrush, and Wyoming big sagebrush. Winter ranges contained more farmland and Columbia Basin grassland, and summer ranges contained more western juniper and ponderosa pine. U.S. Highway 20 bisects a major migration corridor and multiple seasonal ranges, which increases the risk of WVCs. One particularly high-use area occurs where the highway separates two fields of Medicago sativa (alfalfa) pivots near Hampton, Oregon. Paulina pronghorn were present in alfalfa pivots throughout the year, and individuals often incorporated the same pivot into summer and winter ranges. Paulina pronghorn occupy an area containing more than 995 mi (1,601 km) of known BLM fencing because of their range's proximity to residential and agricultural regions. On average, the straight-line paths of pronghorn intersected fences almost 148 times per animal per year. However, this value only incorporates mapped BLM fences and ignores instances where pronghorn approached fences but did not attempt to cross, likely underestimating the true effect on pronghorn behavior.

Sheldon-Hart Mountain Pronghorn

Sheldon-Hart Mountain pronghorn traverse northwest Nevada and southeast Oregon (fig. 21). First published in Kauffman and others (2022a), this updated analysis includes 8 years of additional GPS data from 51 pronghorn. Winter ranges are as far north as Catlow Valley, Oregon, and as far south as the Black Rock Desert, Nevada. Winter range use depends on winter conditions, and almost half the Sheldon-Hart Mountain pronghorn travel to additional winter ranges in more severe winters. The highest use midwinter migration corridors occur between Sage Hen Flats and Big Spring Table, and the highest use spring and fall migration corridors occur between Sage Hen Flats and Little Juniper Mountain. Core summer ranges are near Duhaime Flat, Hart Mountain, Little Juniper Mountain, and Catnip Mountain. One pronghorn traveled 86.5 mi (139 km) to a new range during summer in 2016 before returning to its previous location within the same season. This herd is affected by invasive grasses, habitat loss, juniper encroachment, severe droughts, fences, and WVCs along Oregon/Nevada Route 140. Wildfires in summer range, such as the 2019 Poker fire and the 2024 Warner Peak fire, also spread invasive grasses in areas without sufficient shrub cover.

Surprise Valley Pronghorn

The Surprise Valley pronghorn herd crosses Oregon, Nevada, and California, primarily occupying shrub-steppe communities containing low sagebrush, big sagebrush, and mountain big sagebrush with mixed-conifer forests at some higher elevations. Most pronghorn use winter ranges near Lake Abert and Warner Valley in Oregon and the northeast edge of Surprise Valley in California (fig. 22). Individual seasonal ranges often extend over large areas; some pronghorn travel along Surprise Valley or move between Surprise Valley and Warner Valley during the winter. Summer ranges are near Oregon Route 140, Coleman Valley, Sage Hen Butte, the northwestern rim of Long Valley, and Fort Bidwell, California. In comparison to winter ranges, summer ranges include more mountain big sagebrush and wetland habitats. Summer ranges in higher elevations also contain sections of encroaching western juniper and several low-elevation seasonal ranges around Surprise Valley and Coleman Valley that overlap agricultural areas. Multiple pronghorn migrate across, or have summer ranges adjacent to, Oregon Route 140, which increases the risk of WVCs.

In Oregon, the Surprise Valley herd inhabits the Warner WMU, which has benefited from multiple habitat mitigation projects. Since 2010, more than 49,940 acres (20,210 ha) of western juniper were removed, 13,568 acres (5,491 ha) were treated to eliminate invasive plants, 13,002 acres (5,262 ha) of prescribed burns were completed, and 1,702 acres (689 ha) were reseeded with shrubs and grasses (Oregon Department of Fish and Wildlife, 2015, 202034). In 2023, the NDOW cooperated with the BLM Applegate Field Office to complete a 5.7-mi (9.2-km) fence improvement project that benefitted pronghorn migrating across the Nevada and California State boundary fence near Big Mud Lake and Fee Reservoir (NDOW, 2024). The transboundary nature of this herd will potentially require cooperation among Oregon, Nevada, and California State agencies and stakeholders to ensure migration corridors are unimpeded and seasonal ranges are protected.

Gillette Pronghorn

The Gillette pronghorn herd comprises the North Black Hills and Gillette Herd Units that are separated by State Route 59. In general, pronghorn populations in northeastern Wyoming are understudied, and this work represents the first GPS study to document detailed movement and distribution patterns of pronghorn in this region. This initial study of 35 pronghorn revealed clear interstate movements and migrations of 30–50 mi (48–80 km) between Wyoming and Montana, including occasional facultative winter migrations of Montana pronghorn into Wyoming, and more consistent seasonal migrations of Wyoming pronghorn to summer ranges in Montana. Regardless of the migratory type or State origin, all pronghorn migrations paralleled the Little Powder River, and the heaviest use was on the river’s east side (fig. 23). Pronghorn movements to the south were limited by Interstate 90 in Wyoming and blocked to the north by U.S. Highway 212 in Montana. East and west movements across the Little Powder River and State Route 59 were rare and only documented at the southern extent of the migrations. The region largely comprises private lands interspersed with parcels managed by the BLM. Roadways, fencing, energy development, invasive species, and disease are the primary management concerns for pronghorn herds in this region. This project was initiated by the WGFD, and all animals were captured on winter ranges in Wyoming. Although many of the animals moved north into Montana, Montana Fish, Wildlife & Parks was not directly involved in the project or the resulting maps produced in this report.

Sublette Pronghorn

The Sublette pronghorn herd was originally included in the second volume of the report series (Kauffman and others, 2022a) and is one of the largest pronghorn populations in North America. The management population objective for this herd is 48,000 individuals (WGFD, 2023). During the early 2000s, modeled population size—estimated using aerial line-transect abundance surveys—fluctuated between 31,000 and 62,000 pronghorn. The 5-year average herd size was estimated at 33,700 individuals in 2024, although the herd’s posthunting season population size in 2024 was 26,800 individuals (WGFD, 2024).

Sublette pronghorn winter in the more southern areas of the upper Green River Basin in Wyoming (fig. 24). Depending on winter severity, individual pronghorn winter between Pinedale, Wyoming, in the north, to Rock Springs, Wyoming, in the south, and on the west side of the Red Desert. Winter ranges include a mix of grassland, desert shrub, sagebrush-dominated mesas, and rolling hills. The herd uses a variety of summer ranges, which generally consist of higher-elevation grasslands and sagebrush habitats intermixed with mesic meadows.

Sublette pronghorn have mixed movement strategies: 75 percent of pronghorn tracked with GPS collars (469 females) show migratory behavior with distinct seasonal ranges, and the remaining 25 percent show more nomadic or resident strategies. Sublette pronghorn migrate an average one-way distance of nearly 42 miles (68 km), and some individuals migrate more than 150 miles (241 km). This herd includes some of the longest-distance migrating pronghorn; one pronghorn migrated 200 mi (322 km) from the southern reaches of the range to Grand Teton National Park following Bridger-Teton National Forest Path of the Pronghorn, the first federally designated migration corridor (Berger and Cain, 2014). Others migrate to summer ranges in the Hoback River valley, the Gros Ventre Range, and along the east slope of the Wyoming Range and west slope of the Wind River Range.

Many pronghorn within this herd migrate or winter near energy development, mainly oil and gas development in the Pinedale Anticline, Jonah, and Calpet natural gas fields. Previous research shows pronghorn spend less time in areas after development (Sawyer and others, 2025), and sometimes, pronghorn abandon traditional winter ranges altogether (Reinking and others, 2019). Additional gas wells are permitted in the Normally Pressured Lance field in the center of the Sublette pronghorn herd range, and pressures are increasing from renewable energy sources, such as wind and solar developments along the Interstate 80 corridor in the southern reaches of the herd’s range. However, in 2012–13, Sublette pronghorn benefitted from wildlife overpasses constructed over U.S. Highway 191 at the Trapper’s Point and Boroff Hill sites in high-use parts of the migration route, and an arch crossing structure was constructed to facilitate pronghorn movement across U.S. Highway 189 to the south of Big Piney, Wyoming. In 2024, the Wyoming Game and Fish Department identified the migration corridor as part of Governor Gordon’s Migration Corridor Executive Order 2020–1 (State of Wyoming, 2020), and the process of designating the corridor is currently (2025) ongoing.

San Juan Basin Elk

The San Juan Basin elk herd (DAU E31) is in the southwest corner of Colorado (fig. 25). The DAU is 2,800 mi² (7252 km²) and is bound to the north and east by the Continental Divide, to the south by the New Mexico border, and to the west by the Animas River. Elevations range from 5,000 ft (1,524 m) to more than 14,000 ft (4,267 m). The DAU encompasses Durango, Bayfield, Ignacio, and Pagosa Springs, Colorado, and landownership is a mix of 30 percent private, 12 percent Southern Ute Indian Tribe, 2 percent BLM, and 56 percent FS. Elk generally summer at higher elevations at the northern and eastern part of the DAU and regularly cross the Continental Divide. Elk winter at lower elevations in the southern part of the DAU and into Southern Ute Indian Tribal lands and New Mexico.

Public lands attract multitudes of outdoor recreationists to southwest Colorado, which causes urban, exurban, and recreational development to occur on a large part of critical elk habitat. Development affects the entire DAU, but it is a considerably larger problem near Durango, Bayfield, and Pagosa Springs, Colorado. In addition, one of the largest natural gas fields in the United States overlaps part of the winter range. Several highways, including U.S. Highways 160, 84, and 550, and Colorado State Highways 172 and 151, bisect elk habitat. These roadways affect migrating elk and elk on winter range and increase WVCs. The Southern Ute Indian Tribe and CPW have used GPS-collared data from elk to identify priority habitat, migration routes, timing of migrations, and highway crossing locations. These data and WVC data are used to identify locations for building wildlife-crossing structures.

In 2022, CDOT, the Southern Ute Indian Tribe, CPW, and other partners helped to fund the construction of a wildlife overpass and underpass on a 1.9-mi (3.1-km) section of U.S. Highway 160 near Chimney Rock and the intersection of Colorado State Highway 151. These structures connected an important area of winter range containing high concentrations of elk and mule deer to summer habitats to the north. A multiyear monitoring study was started in 2023 (refer to the “San Juan Basin Mule Deer” section in this report) to determine the effectiveness of the project to reduce WVCs and maintain wildlife movement permeability. Preliminary data analysis (from data collected in October 2023 through June 2024) revealed that the underpass and overpass provide for safe crossings and habitat connectivity for elk and many other wildlife species and increase safer traveling for residents and visitors using the highway (Cramer, 2024).