Mendocino Mule Deer

The Mendocino mule deer herd complex comprises three overlapping Odocoileus hemionus columbianus (black-tailed deer) administrative herds, including Mendocino, Clear Lake, and Alder Springs. Mendocino black-tailed deer exhibit variable movement patterns and strategies, including traditional seasonal migrants, multirange migrants, and full-time residents. Migrants move between seasonal ranges from a multitude of lower elevation areas in the northern Coast Range in winter to higher elevation summer ranges (fig. 5). With a larger dataset, local biologists predict finding high use winter ranges throughout foothill slopes and valley bottoms for this herd’s range. Female deer of the Mendocino herd complex exhibit short-term (seasonal and [or] annual) and long-term (multigenerational) fidelity to their summer ranges (Bose and others, 2017). Population density estimates based on fecal pellet deoxyribonucleic acid (DNA) collected in 2011 and 2012 indicated exceptionally high deer densities on productive summer ranges (131.44 deer per square mile [mi²]; 50.75 deer per square kilometer [km²]; Lounsberry and others, 2015). However, the herd was declining considerably during this period (2011–12) because of low adult survival, including of prime-aged females (Marescot and others, 2015); survival rates were lower than typically observed in other herds (Forrester and Wittmer, 2013). Predation from Ursus americanus (black bears) and Canis latrans (coyotes) was the primary cause of low annual survival of fawns (Forrester and Wittmer, 2019), whereas predation from Puma concolor (mountain lion) was the foremost cause of adult female mortality (Marescot and others, 2015), often in areas deemed less familiar to the individual deer (Forrester and others, 2015). Mountain lion kill rates of black-tailed deer in the study area were the highest reported for their range (Cristescu and others, 2022), probably because of high rates of kleptoparasitism from black bears (Elbroch and others, 2015; Allen and others, 2021). More recent research from California Department of Fish and Wildlife focused on collecting DNA from fecal pellets to update population density estimates (California Department of Fish and Wildlife, 2015) and to determine the herd’s response to catastrophic wildfire (California Department of Fish and Wildlife, 2019; California Department of Forestry and Fire Protection, 2021). Habitat use by black-tailed deer (Bose and others, 2018) and their predators (Cristescu and others, 2019) in the area is well understood, and most of the habitats occupied by the Mendocino herd complex are protected and not at risk of development or fragmentation. However, the threat of catastrophic wildfire and climate change-induced landscape scale changes exist.

Taylor Park Mule Deer

The Taylor Park mule deer herd (Data Analysis Unit D22) inhabits the central part of southwest Colorado (fig. 6) and overlaps with the East Gunnison Basin elk herd (refer to the “East Gunnison Basin Elk” section in this report). The unit encompasses approximately 1,432 mi² (3,709 km²) and is bound on the north by the Elk Mountains and Sawatch Range; on the east and south by the Continental Divide; and on the west by the East River, Gunnison River, and Cochetopa Creek. Elevations in the unit range from approximately 7,700 ft (2,347 m) near Gunnison, Colorado, to more than 14,000 ft (4,267 m) along the Continental Divide. The unit comprises a mix of land ownership and approximately 88 percent public lands. Most private lands are at lower elevations in the unit. Historically, the Taylor Park mule deer herd ranged from 5,000 to 10,000 mule deer, and the current estimate is 6,500 individuals.

During the winters of 2013–22, GPS collars were deployed on 71 adult female mule deer, with two main goals: (1) to measure annual survival rates, and (2) to understand long-term changes in distribution and movement patterns. Although most of the herd summers and winters in this unit, data indicated some individuals summer in the neighboring West Elk unit and some individuals winter in the adjacent Powderhorn unit to the west and southwest, respectively. During early and mild winters, mule deer are distributed throughout the winter range, which includes sagebrush and Populus spp. (aspen) woodland communities at midelevations. As winter severity increases, a commensurate proportion of mule deer move to lower elevations and concentrate along U.S. Highway 50 or the steeper south-facing slopes, such as slopes found in the Cochetopa Canyon along State Route 114 in the southwest section of the Taylor Park mule deer range. The severity of winter conditions amplifies the number of WVC along U.S. Highway 50 east of Gunnison either because mule deer migrate to the Cochetopa Canyon (5–10 mi [8–16 km] away) or because U.S. Highway 50 bisects their winter range. Wintering mule deer face harsh winter conditions with deep snow covering available food sources, causing extreme die offs approximately every 10 years. Ensuring mule deer can continue to move to critical winter range and safely cross roads are conservation priorities for this herd. Many of the same corridors and pinch points used by the Taylor Park mule deer herd overlap with the East Gunnison Basin elk herd.

San Cristobal Mule Deer

The San Cristobal mule deer herd uses a patchwork of winter ranges in the western foothills of the Sangre de Cristo Mountains south of Questa, New Mexico (fig. 7). Winter ranges, bisected by State Route 522, are shared by deer that migrate east and west to summer ranges in the Sangre de Cristo and San Juan Mountains, respectively. The mule deer use multiple migration corridors; most of the herd migrates east into regional national forest and wilderness areas, using shorter, eastern corridors in the Sangre de Cristo Mountains. However, some individuals migrate west from shared winter ranges, moving across U.S. Highway 285, to summer ranges in the San Juan Mountains. Quercus spp. (oak) woodlands, Pinus ponderosa (ponderosa pine), aspen, and mixed-conifer forests characterize the eastern corridors and sagebrush steppe, grasslands, Pinus spp. (pinyon)-juniper mesas, oak woodlands, ponderosa pine, aspen, and mixed-conifer forests characterize the western corridors and stopovers. The eastern corridor is split into two main sections, one heading north and the other heading south. The northern route terminates south of the Red River and west of Columbine Creek. The southern route terminates near Taos Ski Valley northwest of Wheeler Peak, New Mexico’s highest peak (13,167 ft [4,013 m]). Challenges for this herd include potential development on winter ranges and crossing State Route 522 and U.S. Highway 285.

Tesuque Pueblo Mule Deer

The Tesuque Pueblo mule deer herd is primarily nonmigratory, using the foothills of the Sangre de Cristo Mountains (fig. 8). U.S. Highways 84 and 285 are the major routes from Santa Fe, New Mexico, to areas in northern New Mexico and southern Colorado, bisecting Pueblo of Tesuque, New Mexico, and creating a physical barrier for deer movement. GPS collars were deployed on 6 mule deer (3 females and 3 males) to identify where mitigation efforts, like installing underpasses or fencing, may help mule deer cross busy highways successfully and reduce the number of WVC. The female mule deer primarily used the northeastern part of Pueblo of Tesuque, New Mexico, and the southeastern parts of the Pueblo of Nambe, New Mexico. The male mule deer primarily inhabited the urban private lands adjacent to the eastern boundary of Pueblo of Tesuque, New Mexico. Their annual range (50 percent contour) primarily consists of pinyon-juniper woodlands and pinyon-juniper savannahs. The mule deer are culturally significant to the Pueblo of Tesuque, New Mexico, Tribal members.

Urraca Mule Deer

The Urraca mule deer herd inhabits an area north of Questa in north-central New Mexico, on the eastern side of Sunshine Valley and the western base of the Sangre de Cristo Mountains (fig. 9). The winter range primarily comprises sagebrush flats east of State Route 522. The mule deer use two primary migration corridors spanning the Urraca Wildlife Management Area and a mosaic of private lands. The southern corridor follows the Urraca Canyon east and terminates at an approximate elevation of 11,000 ft (3,353 m). The northern corridor runs north of Urraca Canyon and ends southwest of the confluence of Costilla Creek and Comanche Creek in New Mexico, at 9,500 ft (2,896 m). Dense conifer and aspen forests interspersed with meadows and creeks characterize the corridors and stopovers. High-elevation summer ranges are northeast of Latir Peak (12,670 ft [3,861 m]).

Area 17-Toiyabe Mule Deer

The Area 17-Toiyabe mule deer herd inhabits the Shoshone Mountains and Toiyabe Range, which run north to south in central Nevada (fig. 10). Mule deer from the Shoshone Mountains and Toiyabe Range are characterized by short distance migrations from high elevations above 7,874 ft (2,400 m), down to 5,577 ft (1,700 m). Since the 1920s, the lower elevation slopes east of Toiyabe Dome, between Wisconsin Creek and Broad Creek and locally known as Toiyabe bench, have been documented by the Nevada Department of Wildlife as crucial mule deer winter range. Because of the value of this habitat for mule deer, the BLM closed the area to domestic livestock grazing in 1983 (Nevada Department of Wildlife, Bureau of Land Management, and Toiyabe National Forest, 1985). In 2018, in collaboration with Nevada Department of Wildlife, the FS treated 2,600 acres (647 ha) of pinyon and juniper—thinning the woody vegetation wherever they encroached shrublands—on the crucial mule deer wintering habitat (Gundlach, 2022). Other pinyon and juniper treatments are ongoing in Indian Valley, which is an area of high importance for year-round mule deer habitat between the Shoshone Mountains and Toiyabe Range. Senescent browse, reduced forbs, drought, and pinyon and juniper encroachment are the greatest conservation challenges the Area 17-Toiyabe mule deer herd face.

Spring Mountains Mule Deer

The Spring Mountains are critical habitat for the Spring Mountains mule deer herd in southern Nevada. The Spring Mountains west of Las Vegas, Nevada, range in elevation from low meadows at 3,000 ft (910 m) to Charleston Peak at nearly 12,000 ft (3,632 m). Lower elevations are dominated by desert scrub and shrubland, and then transition from Yucca brevifolia (Joshua tree) and pinyon-juniper forest at midelevations to mixed montane conifer including ponderosa pine and Pinus longaeva (bristlecone pine) pine at higher elevations, and sparse alpine grasses and forbs above the tree line. The migratory behavior of the Spring Mountains mule deer herd is variable and is a mix of year-round residents and short-distance elevational migrants. Lovell Canyon serves as a well-used corridor between high-elevation summer range near Mount Charleston, Nevada, and low-elevation winter range near Mountain Springs, Nevada (fig. 11). In 2020, a wildlife underpass was completed to facilitate movement across State Route 160 and reduce WVC. Most of the land in the Spring Mountains is managed by the FS and the BLM and serves as a popular, year-round recreational destination. Encroaching development, prolonged drought conditions, wildfires, feral equids, and human recreation affect the persistence of the mule deer herd in the Spring Mountains.

Beulah-Malheur Mule Deer

With 204 GPS-collared mule deer, the Beulah-Malheur herd is one of the most extensively studied mule deer herds in Oregon. Beulah-Malheur mule deer primarily winter along the Malheur River and the Stinkingwater Mountains, but some mule deer winter as far south as the Owyhee River (fig. 12). Winter ranges contain Artemisia tridentata (big sagebrush), grassland, and encroaching Juniperus occidentalis (western juniper). Although spatially dispersed, much of the Beulah-Malheur mule deer herd collectively migrates northwest to reach summer ranges in the upper elevations of the surrounding national forests to the northwest. Primary summer range vegetation includes A. t. vaseyana (mountain big sagebrush), ponderosa pine, and western juniper with mixed-conifer forests and mountain shrub communities at higher elevations. In 2014, the Buzzard Complex fire burned approximately 398,596 acres (161,306 ha) between Riverside, Oregon, and State Route 78, allowing Taeniatherum caput-medusae (medusahead) and other invasive annual grasses to proliferate in areas originally lacking perennial plant cover. Mule deer cross several major roadways during migration, including U.S. Highway 20, U.S. Highway 26, and U.S. Highway 395, but Interstate 84 is functionally a complete barrier on the eastern edge. The U.S. Highway 20 transects winter ranges for migratory and resident mule deer, and the section between mileposts 135 and 258 along the Malheur River accounted for an average of 179 mule deer-vehicle collisions each year from 2010 to 2022. The Burns Paiute Tribe is working with the Oregon Department of Fish and Wildlife (ODFW) and Oregon Department of Transportation to identify wildlife passage solutions on U.S. Highway 20.

Klamath Basin Mule Deer

The Klamath Basin mule deer herd contains an estimated 10,775 mule deer and is a mix of resident and migratory animals. Most winter ranges are adjacent to the California border near Bly, Oregon, and Lost River, California, in areas with western juniper, low shrublands, and early shrub-tree habitat (fig. 13). In spring, these mule deer either migrate northwest to regional national forest lands or northeast past Oregon Route 140. Summer ranges contain ponderosa pine, mixed-conifer forests, and early shrub-tree habitat along with alfalfa and other agricultural crops. Notably, one GPS-collared mule deer migrated southeast into California near Goose Lake in May 2019 and spent a year near Dead Horse Reservoir before returning to Oregon in November 2020. Out of four mule deer GPS collared during a single capture, one migrated from Lake Abert to Lakeview, Oregon, along U.S. Highway 395 in spring. This stretch of U.S. Highway 395 had an average annual daily traffic (AADT) value of 1,002 vehicles in 2018. Several other mule deer also crossed sections of U.S. Highway 97, an even busier road with an AADT value of 5,298 vehicles in 2018. From 2010 to 2022, Oregon Department of Transportation recorded an average of 65.7 mule deer-vehicle collisions per year along a 44.8-mi (72.1-km) section of U.S. Highway 97 north of Klamath Falls, Oregon. Klamath Basin mule deer numbers are slowly declining, in part because of reduced summer forage quality (Peek and others, 2002). Forest fire suppression beginning in the 1920s increased canopy closure in the summer range, reducing preferred understory vegetation such as Purshia tridentata (antelope bitterbrush) and Ceanothus velutinus (snowbrush ceanothus). Without sufficient high-quality forage during drought years, mule deer become more reliant on agricultural fields near Klamath Falls as a dependable water source. Canopy closure also contributed to the severity of the 2021 Bootleg fire, the third largest recorded fire in Oregon, which burned 413,765 acres (167,445 ha) north of the Sprague River.

Murderer’s Creek Mule Deer

The Murderer’s Creek mule deer herd winters south of U.S. Highway 26 in river valleys near Murderer’s Creek and the South Fork John Day River (fig. 14). The herd’s winter ranges at lower elevations are characterized by western juniper, big sagebrush, Columbia Basin grassland communities, and invasive medusahead and other nonnative grasses. In the spring, mule deer mainly migrate southeast to summer ranges distributed throughout Gilbert Ridge and the Aldrich Mountains, and some deer migrate as far south as Devine Ridge and east to Ironside Mountain. Summer ranges in these areas contain mixed-conifer forests, ponderosa pine, and low sagebrush communities. A smaller portion of this herd migrates northeast in the spring, crossing U.S. Highway 26 to summer near Long Creek, the Blue Mountains, and Elkhorn Ridge; these areas contain big sagebrush, Populus tremuloides (quaking aspen), ponderosa pine, and mixed-conifer forests.

Threats that may affect the Murderer’s Creek mule deer herd include feral horses, habitat degradation, and wildfires. In areas of low-quality browse, Murderer’s Creek mule deer that migrate or reside south of U.S. Highway 26 can compete with feral horses, particularly during drought years. The Murderer’s Creek Herd Management Area (HMA) currently contains 329 feral horses (BLM, 2023), significantly more than the maximum appropriate management level of 140 horses (FS, 2009). In 2010, the Murderer’s Creek Wildlife Management Unit (WMU), which overlaps the Murderer’s Creek HMA, was included in the “Oregon Mule Deer Initiative” to improve conditions for mule deer, primarily through habitat restoration (ODFW, 2011). Since 2010, ODFW, FS, and the Natural Resources Conservation Service have treated 17,295 acres (6,999 ha) for western juniper removal and reseeded 10,016 acres (4,053 ha) for native shrubs and grasses, in addition to temporarily closing 128 mi² (332 km²) of road in the Flagtail Travel Management Area during mule deer hunting season (ODFW, 2015, 2020). In 2015, the Canyon Creek Complex fire burned 110,261 acres (44,621 ha) of the Aldrich Mountains, reducing canopy closure and further improving habitat in summer ranges. The Murderer’s Creek mule deer herd is now stable, and in 2021, had an estimated 5,568 mule deer (ODFW, 2021).

Northside Mule Deer

The winter ranges of the Northside mule deer herd can be broadly separated into northern and southern subgroups. Most of the southern subgroup winters at low elevations near the John Day River in areas dominated by big sagebrush, western juniper, and Columbia Basin grassland communities. The northern subgroup is more spatially dispersed and winters by Cottonwood Creek, the North Fork John Day River, and the Middle Fork John Day River in ranges containing more conifer forest (fig. 15). Both subgroups summer in the same general area, migrating either northeast or southeast to reach areas containing mixed-conifer, Picea spp. (spruce), ponderosa pine, and western juniper forests that have scattered Columbia Basin grassland communities on the Blue Mountains and Elkhorn Ridge. Some mule deer west of the North Fork John Day River migrate north to reach summer ranges near Rock Creek. Five mule deer migrated south, crossing the section of U.S. Highway 26 dividing the Northside and Murderer’s Creek mule deer herds. Because U.S. Highway 26 also separates resident mule deer from agricultural fields with reliable water sources, mule deer-vehicle collisions are common year round, and this section experienced an average of 106 mule deer-vehicle collisions per year from 2016 to 2022. In 2010, the Heppner WMU, which is used for livestock grazing and contains multiple mule deer winter ranges, was included in the “Oregon Mule Deer Initiative” (ODFW, 2015, 2020). Since 2010, ODFW, FS, and the Natural Resources Conservation Service have removed 10,256.7 acres (4,150.7 ha) of invasive flora, reseeded 7,405.3 acres (2,996.8 ha) with native shrubs and grassland, and completed 48 water development projects to improve mule deer habitat.

Southeast Mule Deer

Most of the Southeast mule deer herd winters along the Owyhee River in areas containing sagebrush communities and Columbia Basin grassland communities mixed with nonnative annual grasslands. These mule deer either migrate west to summer ranges on Road Canyon and Gravel Ridges or east to the Owyhee Mountains along the Idaho border. One mule deer migrated 38.3 mi (61.6 km) into Idaho, as far as Bald Mountain (fig. 16). Summer ranges contain shrubland, Columbia Basin grassland communities, western juniper, and evergreen forests. In 2014, the Buzzard Complex fires burned 398,596 acres (161,306 ha), including Road Canyon, allowing medusahead and other nonnative grasses to invade areas with originally low perennial plant abundance. Five mule deer wintered separately near U.S. Highway 95, in areas containing higher percentages of western juniper. In the spring, deer migrated southeast into Nevada to summer on the Santa Rosa Range and one mule deer migrated to the Tuscarora Mountains. Of the Southeast mule deer tracked for at least 100 days, 82 percent migrated seasonally. Several mule deer migrated to summer ranges in different States, which complicated population management. The Southeast mule deer herd faces several challenges, including highways and the low abundance of preferred browse. The northeastern section of U.S. Highway 95 had an AADT value of 2,007 vehicles in 2018 and intersects multiple migration corridors; mule deer commonly cross the highway near Succor Creek. In summer, Southeast mule deer spend more time in riparian zones and may compete with livestock and elk in the Owyhee Mountains for high-quality forage during drought years.

South Wallowas Mule Deer

The South Wallowas mule deer herd’s winter ranges are dispersed in areas of low elevation near the Oregon-Idaho border (fig. 17). During spring, mule deer wintering north of Powder River and Pyles Canyon migrate to Catherine Creek and the Wallowa Mountains in the Wallowa-Whitman National Forest. Interstate 84 is an effective barrier to southern movement for the South Wallowas herd. Mule deer wintering in areas near Interstate 84 are largely residents and only two GPS-collared mule deer migrated to Little Lookout Mountain and Thief Valley Reservoir. Other mule deer reside along the Snake River, which forms the Oregon-Idaho border. One mule deer crossed Snake River south of the Powder River headwaters, migrating 24.46 mi (39.36 km) to Weiser River north of Cambridge, Idaho. The herd’s winter range primarily consists of sagebrush communities and Columbia Basin grassland communities, and summer ranges contain big sagebrush, spruce, quaking aspen, and mixed-conifer forests. Mule deer tend to avoid the lowest elevation areas near Lower Powder Valley, Richland, and Durkee, Oregon, and instead prefer to winter at an average elevation of 3,435 ft (1,047 m) and summer at an average elevation of 5,185 ft (1,580 m). The South Wallowas herd traverses the Keating WMU, which was included in the 2015 “Oregon Mule Deer Initiative” (ODFW, 2020). Since 2015, ODFW, FS, BLM, and the Natural Resources Conservation Service have removed 159 acres (64 ha) of western juniper, reseeded 203 acres (82 ha) with native shrubs and grasses, and thinned 265 acres (107 ha) of timber stands. The effects of ODFW habitat improvements were reduced in 2017 when January snow depth exceeded 30 inches (76 centimeters) in mule deer winter ranges and average overwinter fawn survival dropped to 24 percent; however, fawn survival has since returned to 77 percent in 2018–21 (ODFW, 2021).

Trout Creek Mule Deer

The Trout Creek mule deer herd comprises residents and migrants making short-range elevational migrations. Trout Creek mule deer mainly winter at lower elevations surrounding Blue Mountain and the slopes of the Oregon Canyon Mountains (fig. 18). In spring, some of these mule deer migrate to higher elevations in the Oregon Canyon Mountains. Other individuals winter in the southwestern part of the herd’s range, inhabiting areas near Kings River Valley, the Pueblo Mountains, and the foothills of the Trout Creek Mountains. These mule deer migrate to summer ranges on the crests of Holloway Mountain and the Trout Creek Mountains. Notably, one GPS-collared mule deer formerly wintering on the Trout Creek Mountains migrated south from a summer range on the Oregon-Nevada border to the Montana Mountains during the second documented winter before returning to Oregon in spring. Habitat on winter ranges consists of A. t. wyomingensis (Wyoming big sagebrush) plant communities and nonnative annual grasslands. Summer ranges consist mainly of native grasslands, mountain big sagebrush plant communities, and mountain shrub communities.

The Trout Creek mule deer herd faces several threats including summer wildfires, highway barriers, and resource competition. In 2012, the Holloway fire burned 462,017 acres (186,972 ha) including most of the Trout Creek and Oregon Canyon Mountains and resulted in the temporary loss of shrub cover at higher elevations and conversion of native forbs and shrubland to invasive annual grasses at lower elevations. Although no migratory mule deer attempt to cross U.S. Highway 95, some resident mule deer have ranges spanning the busy highway, which had an AADT value of 2,095 vehicles in 2018. The Trout Creek mule deer herd also borders the Barren Creek Complex HMA to the north and the Beaty Butte HMA to the east (BLM, 2020, 2022). The Barren Creek Complex HMA contains approximately 2,500 feral horses and the Beaty Butte HMA contains 463 feral horses. Both feral horse populations surpass the maximum appropriate management levels of 892 and 250 horses, respectively, suggesting mule deer and horses compete for resources in the few areas where ranges overlap.

Boulder Mule Deer

The Boulder mule deer WMU is part of the high plateau complex in southern Utah. The unit encompasses 1.3 million acres (526,091 ha) including BLM, FS, and State lands and small amounts of private lands on the periphery. Approximately 7,000 mule deer inhabit the area. In 2019, 112 GPS collars were deployed on Boulder mule deer to describe migratory corridors and determine the significance of the winter ranges to the herd. GPS-collar data indicated the Boulder mule deer herd is migratory; mule deer use high-elevation habitats on FS lands in the summer and low-elevation habitats on BLM and State lands in the winter (fig. 19). Herd movements appear complex because mule deer sharing the same summer range have the option to migrate to many different winter ranges. A better understanding of the herd’s movements is critical for managing the herd and keeping corridors and winter ranges intact.

Wasatch East Mule Deer

The Wasatch East mule deer herd resides on the eastern side of the Wasatch Range in central Utah. Annually, the Wasatch East mule deer migrate an average of 23 mi (37 km) between summer ranges along Duchesne Ridge, north of Strawberry Valley, and winter ranges west of Duchesne, Utah, near Tabby Mountain and Rabbit Gulch (fig. 20). Winter range habitat consists of pinyon-juniper woodlands, sagebrush-grass, and mountain browse communities. These habitat types are used heavily by wintering big game species and browsing availability is greatly reduced in severe winters, which pushes the Wasatch East mule deer herd into agricultural areas. The herd’s winter range habitats are at high risk of habitat loss and degradation, threatened by conifer encroachment, expansion of invasive species, and increasing development. The Utah Division of Wildlife Resources is actively restoring sagebrush and other browse species to recover and enhance winter habitat for mule deer and other wildlife. Additionally, highway mortality is a significant concern for this herd because mule deer must traverse two major highways, U.S. Highway 40 and U.S. Highway 191. Bisecting this corridor, U.S. Highway 40, a major transportation corridor, has seen an upward trend of AADT and saw nearly 6,000 vehicles per day in 2020 (Utah Department of Transportation, 2023). Approximately 2,000 vehicles per day travel U.S. Highway 191 (Utah Department of Transportation, 2023), which forms the southeastern boundary of the Wasatch East mule deer herd. Cooperative efforts with the Utah Department of Transportation are underway to accurately implement mitigation measures on sections of both highways to reduce WVC.

Zion Mule Deer

The Zion mule deer herd inhabits the Zion WMU in southern Utah, is one of the larger deer herds in the State, and has approximately 18,000 animals. The Zion WMU has a unique assemblage of flora and fauna in addition to various geographical configurations such as canyons, buttes, mesas, and natural arches. Land ownership is a complex mix of BLM, NPS, FS, and private lands. A significant portion of the Zion mule deer herd’s summer and winter habitats is on private land. The BLM, FS, and Zion National Park administrate the remaining portions (fig. 21). Data from GPS-collared mule deer indicated most mule deer are migratory, traveling north and south to reach their respective seasonal ranges. Additionally, mule deer must navigate State Route 9, which connects nearby major cities to Zion National Park. As a result, urban development and vehicular collisions are the herd's predominant challenges in this migration corridor. The Utah Division of Wildlife Resources continues to work closely with landowners and land management agencies to protect and enhance existing, crucial mule deer habitat and mitigate losses because of natural and human effects.

Klickitat Mule Deer

The Klickitat mule deer herd inhabits the Columbia Hills and surrounding terrain to the north along the Columbia River, Washington (fig. 22). Klickitat River bounds the western edge of the herd’s range and is part of a transition zone between black-tailed deer and mule deer distributions. Habitats in the western half of the herd’s range include Quercus garryana (Oregon white oak) mixed with Abies spp. (fir), pine, or grassland species. The western half of the herd’s range comprises a mix of public and private lands, including rangeland, farmland, and the Klickitat Wildlife Area, which has protected crucial winter range since the 1950s. Sagebrush steppe is more prevalent in the eastern half of the herd’s range with Oregon white oak and ponderosa pine in drainages, such as Rock Creek, which serves as a popular wintering area. Dryland wheat, rangeland, and viticulture are also common in the eastern half of the herd’s range, which is mostly privately owned.

Klickitat mule deer are partially migratory; more residents inhabit the eastern half of the herd’s range, and a higher proportion of migrants are in the western half of the herd’s range. As vegetation green up progresses during spring, migrants travel from low-elevation winter ranges to high-elevation summer ranges in the Cascade Range and Simcoe Mountains. Some individuals migrate short distances (5 mi [8 km]), especially mule deer in the eastern half of the herd’s range. Increasing residential development in the western half of the range, and renewable energy development and conversion to viticulture in the eastern half of the range, are the greatest concerns for winter ranges and migration corridors. Additionally, U.S. Highway 97 is a semipermeable barrier to migration and only has one wildlife underpass, which was built in 2012.

Wenatchee Mountains Mule Deer

The Wenatchee Mountains mule deer herd inhabits a matrix of private and public lands along the eastern slope of the Cascade Range in Washington (fig. 23). Historically, the Wenatchee Mountains mule deer herd was separated into two subherds, Chelan and Kittitas; however, recent GPS-collar data indicated the mule deer south of U.S. Highway 2 and north of Interstate 90 represent one herd. Their high use winter range extends along the foothills west and south of Wenatchee, Washington, and throughout the foothills of Kittitas Valley near Ellensburg, Washington. Their low use winter range occurs along the foothills west of the Columbia River north of Interstate 90. In the spring, migratory mule deer travel west into the Wenatchee Mountains to their summer range, which includes regional wilderness areas.

Between 2020 and 2021, collaring efforts focused on the foothills near Wenatchee, Washington, and in the surrounding foothills near Ellensburg. Collar data analysis indicated the Wenatchee Mountains mule deer herd is partially migratory. A high proportion of migratory mule deer inhabit the northern winter range of the Wenatchee Mountains, and residents more commonly inhabit the foothills of Kittitas Valley. In 2022, collaring efforts in the northern winter range foothills near Wenatchee targeted the higher proportion of the migratory herd of mule deer, to more clearly identify the movement corridors intersecting U.S. Highway 97 near Blewett Pass. The herd has several challenges, including the increasing frequency of large-scale wildfires and residential developments, which continue to degrade and reduce available winter habitat. Disturbance from human recreation on the winter range continues to be a concern. Additionally, U.S. Highway 97 and State Route 970 receive high volumes of traffic in the region and present semipermeable barriers to spring and fall migrations.

Clear Lake Pronghorn

The Clear Lake pronghorn herd contains migrants, but this herd does not migrate between traditional summer and winter seasonal ranges. Instead, much of the herd displays a nomadic tendency and slowly migrates north, east, or south for the summer using various high use areas as they move. Therefore, annual ranges were modeled using year-round data to demarcate high use areas instead of modeling specific winter ranges. A few GPS-collared pronghorn lived west of State Route 139 year round, seemingly separated from the rest of the herd by this highway barrier (fig. 24). However, some pronghorn crossed this road near Cornell, California, and joined this subgroup. Summer ranges were dispersed, and many individuals moved southeast through protected forests or crossed the State border into Oregon. A few outliers in the herd migrated long distances south, either crossing State Route 139 to Oak Ridge, or east into areas used by Likely Tables pronghorn (refer to the “Likely Tables Pronghorn” section in this report). Many of the collared pronghorn heavily used areas adjacent to Clear Lake Reservoir during winter. The Clear Lake pronghorn herd is declining (Trausch and others, 2020) because of drought, increasing fire frequency, invasive annual grasses, and juniper encroachment. Juniper removal on public and private lands could improve habitat quality and potentially reduce predation from mountain lions (Ewanyk, 2020).

Lassen Pronghorn

The Lassen pronghorn herd winters in lower elevations in Secret Valley, Bull Flat, and wilderness areas east of Shaffer Mountain and northeast of the Skedaddle Mountains. Summer ranges are dispersed with some pronghorn migrating north to the Madeline Plains and other pronghorn heading west to Willow Creek Valley, Grasshopper Valley, and Eagle Lake (fig. 25). An unknown portion of the herd is better characterized as residents. The primary threat to the Lassen herd is the conversion of perennial shrublands to nonnative, annual grasslands following wildfires. The 2012 Rush fire burned 271,911 acres (110,038 ha) in Lassen County by the herd’s boundary and expanded nonnative annual grasslands with altered fire regimes, which increase fire frequency and promote further expansion of nonnative grasses. Overabundant feral horses and burros regularly exceed the appropriate management level, potentially reducing forage and water available for pronghorn (California Department of Fish and Wildlife, 2022). The expansion of juniper into shrub-steppe habitat reduces the forage available to pronghorn and increases the risk of mountain lion predation. Since the 1992–93 winter die off in northeastern California, the herd has been stable or slightly increasing with an average of 974 pronghorn counted during aerial winter surveys (B. Ehler, California Department of Fish and Wildlife, written commun., 2023). California Department of Fish and Wildlife plans to deploy 35 pronghorn GPS collars in winter 2024 to estimate the herd size using mark-resight surveys.

Likely Tables Pronghorn

The Likely Tables pronghorn herd contains migrants, but this herd does not migrate between traditional summer and winter seasonal ranges. Much of the herd displays a nomadic tendency and slowly migrates north for the summer using various high use areas as they move. Annual ranges were modeled using year-round data to demarcate high use areas instead of modeling specific winter ranges. However, during winter, many of the GPS-collared pronghorn heavily use an area west of the Warner Mountains, east of U.S. Highway 395, and north of Moon Lake (fig. 26). Some animals live year round in the agricultural fields and higher elevation prairies west of U.S. Highway 395. Little, if any, movement occurs by the herd across the highway, which is fenced on both sides of this area in the winter range. Summer ranges are dispersed with some pronghorn moving as far north as Goose Lake. A few outlier pronghorn in the herd move long distances south toward the Lassen pronghorn herd (refer to the “Lassen Pronghorn” section in this report) or east to Nevada. The Likely Tables pronghorn herd is declining because of drought, increasing fire frequency, invasive annual grasses, and juniper encroachment (Trausch and others, 2020). Juniper removal on public and private lands could improve habitat quality and potentially reduce predation from mountain lions (Ewanyk, 2020). Additionally, fences on public and private lands affect movement corridors and increase crossing or migration duration. However, recent fence modifications on BLM lands showed potential to reduce barriers to pronghorn movements (Hudgens, 2022).

Mount Dome Pronghorn

The Mount Dome pronghorn herd contains a mixture of residents and short-distance, elevation-based migrants, but this herd does not migrate between traditional summer and winter seasonal ranges. Instead, most of the herd displays a somewhat nomadic migratory tendency and slowly moves up or down elevational gradients. Long distance movements from this herd are rare because it is largely surrounded by geographic and human features restricting movement. Some pronghorn use higher elevation areas throughout the summer, although this pattern was not common. Therefore, annual home ranges were modeled using year-round data to demarcate high use areas (fig. 27). Mount Dome pronghorn numbers have declined significantly from historical highs but have remained relatively stable at low numbers in recent years (Trausch and others, 2020). Agricultural development in Butte Valley resulted in some loss of historical pronghorn habitat. Drought, increasing fire frequency, invasive annual grasses, and juniper encroachment negatively affect remaining, available habitat for pronghorn. Juniper removal on public and private lands has the potential to improve habitat quantity and quality (Ewanyk, 2020).

Carter Mountain Pronghorn

The Carter Mountain pronghorn herd contains approximately 7,000 pronghorn—half which migrate 10–60 mi (16–97 km) west from common winter ranges in the Bighorn Basin to summer ranges near the Absaroka Range (fig. 28). During this migration, pronghorn must cross U.S. Highway 14 and Wyoming Highway 120. Most pronghorn summer in ranges west of Wyoming Highway 120 along the Greybull River, but some pronghorn summer in the South Fork Shoshone River drainage. Some of the herd gains nearly 6,000 ft (1,829 m) in elevation to summer on the high plateaus of the Absaroka Range and upper Greybull River and at 10,000–11,000 ft (3,048–3,353 m) above sea level in alpine meadows they share with Ursus arctos (grizzly bear) and Canis lupus (wolf) populations. Challenges to this herd’s migration include multiple highway and fence crossings. Habitat loss and fragmentation from residential development are also a concern.

South of Interstate 40 Elk

The South of Interstate 40 elk herd primarily resides in Arizona Game Management Unit 8. Population surveys in 2021 estimated approximately 4,000 elk inhabited Game Management Unit 8. The elk herd’s summer range is primarily characterized by high-elevation ponderosa pine forests and grasslands. The elk migrate from various origin points in their summer range to their winter range, which comprises canyon rims in the area (fig. 29). This series of canyons creates an impermeable southern boundary for this herd. Their winter range along the canyon rim area is primarily characterized by pinyon-juniper, Arctostaphylos spp. (manzanita), and Quercus ilicifolia (bear oak). Interstate 40 is the primary threat to this herd’s migration corridor, which limits habitat connectivity and highway permeability between the South and North of Interstate 40 elk herds (Arizona Game and Fish Department, 2021; Kauffman and others, 2022a). Successful elk crossings of Interstate 40 are rare, and more than 65 WVC occur in this area per year (Arizona Game and Fish Department, 2021). To help mitigate this issue, an overpass is being planned, which could potentially connect these two herds across Interstate 40.

East Gunnison Basin Elk

The East Gunnison Basin elk herd (Data Analysis Unit E43) inhabits the central part of southwest Colorado and overlaps with the Taylor Park mule deer herd (refer to the “Taylor Park Mule Deer” section in this report). The area encompasses approximately 1,432 mi² (3,709 km²) and is bound on the north by the Elk Mountains and Sawatch Range; on the east and south by the Continental Divide; and on the west by the East River, Gunnison River, and Cochetopa Creek (fig. 30). Elevations in the East Gunnison Basin unit range from approximately 7,700 ft (2,347 m) near Gunnison, Colorado, to more than 14,000 ft (4,267 m) along the Continental Divide. The area comprises a mix of land ownership and approximately 88 percent public lands. Most of the private lands are at lower elevations. Historically, the East Gunnison Basin elk herd ranged from 4,000 to 8,000 animals and is currently estimated at 6,900 elk.

During the winters of 2015–22, GPS collars were deployed on 74 adult female elk with the goal of measuring long-term changes in elk distribution patterns and annual survival rates. In general, the GPS-collar data revealed elk seasonally migrate 30–40 mi (48–64 km) in midfall (November) from the highest elevations on the northern and eastern fringes of the unit to the lower elevation winter ranges (approximately 8,000–9,000 ft [2,438–2,743 m] in elevation). The data revealed 20–40 percent of the herd migrates from their typical winter range midwinter (December to February), moving southeast (10–30 mi [16–48 km]), and crossing the Continental Divide (peaking at approximately 10,000–11,000 ft [3,048–3,352 m] in elevation) to finish wintering in areas with less snowpack in the San Luis Valley on the eastern slope of the Continental Divide. The proportion of the herd making this midwinter migration appears to depend on winter conditions in their typical winter range, with approximately 50–70 percent leaving during the years with deeper snowpack. Elk survival declines substantially in these harsh winters, emphasizing the importance of maintaining their ability to move to milder conditions, such as those conditions found across the Continental Divide. The elk making the longest migrations use a network of 3–4 corridors at least 74 mi (119 km) long, which cross U.S. Highway 50, State Route 114, and the dense forests and deeper snowpack along the Continental Divide. State Route 135, which parallels the Gunnison River and East River on the northwestern border of the East Gunnison Basin unit, creates a significant barrier to neighboring elk in the West Elk Mountains unit. However, an estimated 500–750 elk (depending on the conditions) move between the two units by using historically known sites across the river and paralleling the highway. Many of the same corridors and pinch points used by the East Gunnison Basin elk herd overlap the Taylor Park mule deer herd.

Jemez Elk

The Jemez elk herd primarily resides in the Jemez Mountains in the Valles Caldera National Preserve (fig. 31). The herd was originally included in Kauffman and others (2022a) but has been updated for this report because of new GPS-collar data available from 40 additional adult females. The Jemez elk are only partially migratory; some residents remain year round in the Valles Caldera National Preserve and others exhibit two distinct seasonal movement patterns. The first movement pattern occurs during midwinter (January–February) when numerous elk move to the lower elevation slopes of the Valles Caldera National Preserve, primarily southeast towards Bandelier National Monument. The second movement is more typical of a spring and fall migratory movement; elk migrate north to La Grulla Plateau for the summer and return to the Valles Caldera National Preserve for the winter. The primary challenge for migrants is crossing State Route 4 when traveling to Bandelier National Monument.

Rio Chama Elk

The Rio Chama elk herd inhabits north-central New Mexico, near Tierra Amarilla (fig. 32). This herd’s winter range is predominately west of U.S. Highway 84 between the Heron and Abiquiu Reservoirs. The Rio Chama elk herd migrates through a mosaic of private, public, and Jicarilla Apache Nation, New Mexico lands, using three primary migration corridors: the northern and eastern corridors near Heron Reservoir and the northeastern corridor near Abiquiu Reservoir. Elk using the northern corridor near Heron Reservoir follow a variety of routes; some elk only migrate approximately 6 mi (9.7 km) to summer along the Rio Chama and other elk migrate more than 30 mi (48.3 km) to southern Colorado. The eastern migration corridors are approximately 10 mi (16.1 km) and cross U.S. Highways 84 and 64 south of Tierra Amarilla before settling in the western San Juan Mountains. Elk near the Abiquiu Reservoir commonly migrate northeast and cross State Route 84 into the San Juan Mountains to their summer range southeast of Canjilon, New Mexico. The herd faces several challenges, such as crossing State Route 112 and U.S. Highways 84 and 64, increasing density of housing subdivisions in some areas along their migration, and fencing, especially taller fencing that elk cannot jump.

Tesuque Pueblo Elk

The Tesuque Pueblo elk herd is primarily nonmigratory. The elk in this herd came to the region in the late 1990s and early 2000s, likely because of displacement by large fires in the Jemez Mountains. U.S. Highways 84 and 285 bisect Pueblo of Tesuque, New Mexico, and create a physical barrier for elk movement, which contributes to potential WVC. GPS collars were deployed on two female elk to track the habitat and lands used by this herd. The elk seasonally use the western section of Pueblo of Tesuque, New Mexico (fig. 33). Similar to the Tesuque Pueblo mule deer herd (refer to the “Tesuque Pueblo Mule Deer” section of this report), the annual range (fig. 33) of the Tesuque Pueblo elk herd primarily consists of pinyon-juniper woodlands and pinyon-juniper savannah. The elk use the southwest area of Pueblo of Tesuque, New Mexico, and private lands southwest of the reservation. The herd also uses BLM and FS lands adjacent to Pueblo of Tesuque, New Mexico, in the Caja del Rio Plateau. A lower elevation and drier section of the FS lands, the Caja del Rio Plateau is a pinyon-juniper-dominated vegetation zone with areas of sage and mixed grasses. The elk are culturally significant to Pueblo of Tesuque, New Mexico, Tribal members.

Colockum Elk

The Colockum elk herd inhabits a mix of public and private lands northeast of Ellensburg, Washington, between Blewett Pass of the Cascade Range and west of the Columbia River (fig. 34). The herd size ranges between 4,000 and 5,000 elk and is partially migratory; the herd includes a mix of resident (63 percent of GPS-collared elk) and migratory (34 percent of GPS-collared elk) behaviors. During winter, many elk inhabit grassland, sagebrush, antelope bitterbrush, and ponderosa pine habitats in the Whiskey Dick, Quilomene, and Colockum Wildlife Areas and the eastern reaches of the Naneum Ridge State Forest. As spring green up of vegetation nears, migratory elk travel northwest toward summer ranges in the Wenatchee Mountains, north of Ellensburg, Washington. Resident elk inhabit the same areas as wintering migratory elk. Agricultural producers in the eastern Kittitas Valley often experience conflicts with elk consuming hay in fields. Additional concerns for the herd include semipermeable barriers along Interstate 90 and U.S. Highway 97 and disturbance from human recreation on the winter range.

Owl Creek Elk

The Owl Creek elk herd—between 7,500 and 8,500 wintering elk—inhabits the northwest corner of the Wind River Reservation, traversing habitats along the Absaroka Range and the Owl Creek Mountains (fig. 35). The herd contains resident and migratory elk; migrants travel an average 10.7 mi (17.2 km) one way. Elevations range from 6,000 ft (1,829 m) at the Wind River near Crowheart, Wyoming, to 12,200 ft (3,700 m) in the Absaroka Range, and summits in the Owl Creek Mountains, which reach 8,000–9,800 ft (2,438–2,987 m). Habitats range from sage and desert scrub in the lowlands to upland meadows, aspen groves, Pinus contorta (lodgepole pine) forests, and alpine tundra. When on the Wind River Reservation, the elk are under the sovereignty of the Eastern Shoshone Tribe of the Wind River Reservation, Wyoming, and Northern Arapaho Tribe of the Wind River Reservation, Wyoming. During spring migration, some elk cross the East Fork Wind River to FS lands. Other migrations are entirely within the reservation, including the upper tributaries near Washakie Needles or the Owl Creek Mountains. Residents in the herd also use the Owl Creek Mountains, particularly the part east of Blondy Pass. Many areas contain significant evidence of past hunting and ceremonial activity, and according to Shoshone ethnography, elk were significant game acquisition in the prereservation era of the 1800s (Shimkin, 1947). This elk herd remains culturally and economically valuable to Tribal members who sustainably harvest elk under a game code established in 1984 (Nickerson, 2019; Wind River Tribal Court, 2004). Habitats are virtually free of human disturbance and development aside from Tribal member livestock grazing and a few Tribal-owned and operated oilfields in the desert winter range. Threats to habitat include drought and climate change or biological invasions of nonnative cheatgrass and feral horses contributing to poor range conditions. In 2022, Tribes started working in partnership with the Bureau of Indian Affairs Wind River Agency, U.S. Fish and Wildlife Service, Wyoming Game and Fish Department, Wyoming Legislature, Wyoming Livestock Board, and the Wild Sheep Foundation to reduce the feral horse population and design projects to restore habitats to greater productivity (Nikonow, 2023).

Wind River Elk

The eastern slope of the Wind River Range provides habitat to approximately 4,000–5,000 migratory elk. The Wind River Elk herd winters on the Wind River Reservation, which is managed under the sovereignty of the Eastern Shoshone Tribe of the Wind River Reservation, Wyoming, and the Northern Arapaho Tribe of the Wind River Reservation, Wyoming (fig. 36). In spring, the herd migrates up in elevation to a roadless area established by the Tribes in the late 1930s—decades before The Wilderness Act of 1964 (Public Law 88–577, 16 U.S.C. 1131–1136)—or to adjacent FS lands. Many of the migration routes are along waterways that have significant cultural heritage, including petroglyphs in the Dinwoody-style and areas connected to stories of sacred figures and occurrences (Wind River Visitors Council, 2022). Elk are a prominent part of ongoing Tribal cultural and language revitalization efforts. Collared elk migrate through historical hunting pits and drive lines used by Native peoples thousands of years ago. The herd is actively hunted by Tribal members per a harvest regulation code (Nickerson, 2019; Wind River Tribal Court, 2004). The terrain ranges from 6,000 ft (1,829 m) to 12,000 ft (3,658 m), but most elk summer at elevations below 11,000 ft (3,353 m). Foothill habitats contain grass and sage, whereas the rocky Wind River Range contains alpine, lodgepole pine forests, mixed grass-conifer basins and ridges, and Salix spp. (willow)-lined creeks. The foothills have minimal development, except for irrigation infrastructure at Bull Lake and Washakie Reservoir and fenced ranches near Crowheart, Wyoming. Elk routinely winter in the remote foothills of the Wind River Range and near the more developed areas of Boulder Flats, Fort Washakie, and Lander, Wyoming. However, near Crowheart Butte and Bighorn Flat, groups of elk sometimes cross U.S. Highways 26 and 287 to the north or east, putting them at risk for elk-vehicle mortality.

Jackson Moose

The Jackson moose herd inhabits an area 2,023 mi² (5,239 km²) northwest of Jackson, Wyoming, in the lowlands of the Snake River. The Jackson moose herd was historically abundant and had a peak of 3,000–5,000 moose in the early 1990s. However, the herd declined significantly following the large counts in the early 1990s and continues to decline with an average count of 280 moose between 2016 and 2020 (Wyoming Game and Fish Department, 2022b). The migrations of the northern portion of the herd were published in Kauffman and others (2020a). The southern portion of the herd, presented here, resides near Wilson, Wyoming, and is partially migratory. Many of the migratory moose move from low-elevation winter ranges along the Snake River to high-elevation summer ranges in the surrounding national forests and Grand Teton National Park (fig. 37). Winter ranges are characterized by riparian, mountain shrub, and aspen communities, and summer ranges include montane meadows and forested habitats. The Snake River corridor serves as a movement pathway between the southern and northern areas and provides an important riparian food resource. Migration distances range from <1 mi (<1 km) to roughly 13 mi (21 km). Despite hunting season closures and a reduction in licenses, this herd has not responded to management changes and continues to be closely monitored by regional wildlife management agencies.