The Imnaha subbasin is inhabited by approximately 12 amphibian species, 19 reptile species, 239 bird species, and 69 mammal species (refer to Appendix D) (Wallowa-Whitman National Forest 1998). Some of these species, including many of the birds, only reside in the area for short periods of the year during their migration (Wallowa-Whitman National Forest 1998). The list of 339 wildlife species present in the subbasin was developed using information available from watershed assessments and restoration planning documents for the subbasin (Wallowa-Whitman National Forest 1998).
Most of the wildlife species of the Imnaha subbasin are thought to have healthy and stable populations but there are many exceptions. Many of the wildlife species within the subbasin need special consideration by managers because of known declining populations or unknown population statuses. Over a dozen endangered, threatened, or sensitive species on the Regional Forester’s sensitive species list are known to exist within the subbasin, include the subbasin in their recovery zone, or have questionable population viability (Wallowa-Whitman National Forest 1998). Table 25 shows that 38 species in the subbasin are listed or candidates for listing at the state or federal level.
The subbasin is also home to many valuable game species. Game species harvested in the Imnaha subbasin include mule and white-tailed deer, Rocky Mountain elk, black bear, cougar, turkey, pheasant, California quail, chukar partridge, Hungarian partridge, forest grouse, snipe, and mourning dove. Trapped furbearers include beaver, coyote, mink, muskrat, otter, skunk, raccoon, and weasel (Oregon Department of Fish and Wildlife 2000).
Table 25. State, federally listed, or candidate wildlife in the Imnaha subbasin (ODFW website 2000; ODFW 1997; USFWS 2001; USDA Forest Service Pacific Northwest Region 2000; Wallowa-Whitman National Forest 1995; Marshal et al. 1997)
The large number of wildlife species that occur in the Middle Snake subbasin makes management on a species by species basis impractical. Wildlife management in the subbasin is conducted in an ecosystem-based framework with the goal of providing a variety of wildlife habitat conditions in all vegetative communities (Wallowa-Whitman National Forest 1999). To facilitate the discussion, wildlife species will be discussed based upon Wisdom et al.’s (2000) habitat requirement families. In constructing the families, Wisdom selected species that serve as indicators of ecosystem health and for which there is concern about habitat or population status. Representatives of 22of the 12 families designated occurring in the subbasin some cases similar families have been grouped together to facilitate the discussion. Population and trend data are discussed for wildlife species in the family when available.
Old-Forest Dependent Species
Over two-dozen species in the subbasin belong to Wisdom’s low-elevation old forest or broad-elevation old forest families. Varying levels of information are available concerning the population status of these species. Many species within these families are management indicator species for the Wallowa-Whitman National forest. They include the American or pine marten (Martes americana), white-breasted nuthatch (Sitta carolinensis), pygmy nuthatch (Sitta pygmaea), Lewis woodpecker (Melanerpes lewis), pileated woodpecker (Dryocopus pileatus), Williamson’s sapsucker (Sphyrapicus thyroideus), white-headed woodpecker (Picoides albolarvatus), black-backed woodpecker (Picoides arcticus), northern goshawk (Accipter gentilis), and three-toed woodpecker (Picoides tridactylus).
The pileated woodpecker, the largest woodpecker in North America is one of the most sensitive primary cavity nesters because of its large size (Wallowa-Whitman National Forest 1999). This species relies on old-forest habitat, and particularly upon large diameter snags and fallen trees under a canopy with at least 60% closure (Wallowa-Whitman National Forest 1998). Viable populations of pileated woodpeckers and other primary excavators are essential for maintaining populations of secondary cavity users (Cassirer 1995). Pileated woodpecker pairs have been documented in the subbasin during timber sale surveys (Wallowa-Whitman National Forest 1998). The HCNRA provides large amounts of unharvested forest much of it with high densities of snags and down wood habitat. In these areas populations of primary excavators are thought to be near natural population levels (Wallowa-Whitman National Forest 1999).
American marten individuals are known to occur in the subbasin, but little other population information exists (Wallowa-Whitman National Forest 1998). Winter track snow surveys located some marten tracks, with most of them occurring in late or old growth forest habitat (Wallowa-Whitman National Forest 1998). Martens need old forest habitat with snags and down wood to provide prey habitat and canopy closure to protect them from predation (Wallowa-Whitman National Forest 1998).
Flammulated owls also depend upon old-growth forests. Flammulated owl habitat tends to be a mosaic containing densely forested areas, grasslands, and areas with old-growth ponderosa pine (Wallowa-Whitman National Forest 1998). Population information for the subbasin is unknown, but reductions in ponderosa pine habitat suggest that the population size may be lower than historic levels (Wallowa-Whitman National Forest 1998).
The northern goshawk is a seasonal member of the old-forest dependent family it belongs to this family in the summer and the forest, woodland, and shrub dependent family in the winter. Nesting surveys in timber sale areas of the subbasin have located nests in old mixed-conifer stands (Wallowa-Whitman National Forest 1998; Wallowa-Whitman National Forest 1995). The Big Sheep Creek watershed’s northern goshawk population is smaller than the potential population size for the area (Wallowa-Whitman National Forest 1995).
Blue grouse breed in open foothills and are closely associated with streams, springs, and meadows during spring and summer. In the fall they migrate to higher elevations where they spend the winter feeding on fir needles. Large fir trees are a food source for wintering blue grouse and are required for roost sites. Blue grouse exhibit strong site fidelity to their wintering areas in true fir (Abies spp.) and Douglas fir (Pseudotsuga menziesii) forests (Larsen and Nordstrom 1999). Populations of Blue Grouse in Wallowa County have exhibited significant variation in the past 40 years. Counts conducted by ODFW of blue grouse per 10 miles ranged from 1.0 –8.9 during the period from 1961 to 1999. In 1999 5.2 birds per 10 miles were counted which is just above the averade of 4.7 (ODFW unpublished data).
Figure 23. Blue Grouse poulation trends (birds/10 miles) Wallowa County 1961-1999 (ODFW unpublished data)
Forest Mosaic Dependent Species
Three species, the wolverine (Gulo gulo), the lynx (Lynx canadensis), and the blue grouse (Dendragapus obscurus), belong to the forest mosaic dependent family. From 1991 to 1994, wolverine surveys were conducted by the Wallowa-Whitman National Forest (WWNF) and concluded that wolverines were rare within the area (Wallowa-Whitman National Forest 1998). Eight sightings of wolverines have been reported to the Oregon Natural Heritage program in the Imnaha subbasin. The lynx was believed to have been extirpated from Oregon, but some believe they may still inhabit the state (Wallowa-Whitman National Forest 1995). The Oregon Department of Fish and Wildlife considers the species extirpated from Oregon (Wallowa-Whitman National Forest 1999). Two occurrences of lynx have been reported to the Oregon Natural Heritage Program in the Imnaha subbasin. No lynx reports have been confirmed for many years and surveys for lynx conducted simultaneously with the wolverine surveys by WWNF found no evidence of lynx (Wallowa-Whitman National Forest 1998). Blue grouse has a seasonally split membership in this family and the old-forest dependent family. Population information for blue grouse is discussed in the old-forest dependent species section.
Forest Mosaic and Forest Range Mosaic Dependent Species
Four species, the mountain goat (Oreamnos americanus ), the Rocky Mountain big horn sheep (Ovis canadensis), the long-eared owl (Asio otus), and the western bluebird (Sialia mexicana), inhabiting the subbasin belong to the forest mosaic, and forest and grassland mosaic dependent families.
Rocky mountain bighorn sheep have been present in the subbasin for thousands of years (Wallowa-Whitman National Forest 1995). Archeological evidence from Downey Gulch suggests that the ridge was used to drive sheep into a corral 3410 years ago (Wallowa-Whitman National Forest 1995). Early Anglo-American settlers noted the presence of big horn sheep and considered them a pest because they competed with livestock (Wallowa-Whitman National Forest 1995). Overhunting, poor range conditions, and domestic sheep diseases led to the extirpation of bighorn sheep from Oregon in the 1940s (Oregon Department of Fish and Wildlife 1992c). Between 1979 and 1984, 36 bighorns were released into the subbasin; these animals originated from the Salmon River and Jasper National Park bighorn sheep populations (Idaho Fish and Game et al 1997). The population of this herd was estimated to be 115 in 1999(Oregon Department of Fish and Wildlife unpublished data). Bighorn hunting permits are in high demand but their issue is carefully controlled by Oregon Department of Fish and Wildlife. Between 1979 and 1996, 48 bighorn sheep permits were issued for the Imnaha bighorn sheep herd through auction and lottery. These permits resulted in the harvest of resulting in the harvest of 45 bighorns; the Imnaha herd provides more hunting opportunities than neighboring herds (Idaho Department of Fish and Game et al 1997).
Reestablishment of bighorn populations in most areas has been hampered by reoccurring pneumonia die-offs. Pasturella haemolytic and multicida bacteria have been identified as the primary causes of pneumonia in bighorns and are often the result of contact with domestic sheep. Sheep grazing, once prevalent in the Imnaha subbasin, no longer occurs (D Bryson NPT, personal communication May 2001).
Big horn sheep habitat consists of steep rocky open terrain with abundant bunchgrasses. Lambing occurs on steep cliffs, which helps the young avoid predation (USDA Forest Service 1999). The pumpkin creek drainage was highly rated as a potential release site based on the availability of lambing and winter range habitat and a low risk of exposure to domestic sheep populations.
Mountain goats were extirpated from northeast Oregon prior to European settlement. Moutain goats were reintroduced to the area four times and the descendents of these goats now comprise the Wallowa Mountain herd. In 2000 the population of the Wallow mountain herd was estimated at 150 goats. Goats are beginning to pioneer vacant habitat adjacent to traditional core use areas, which will help to establish subpopulations throughout the Wallowas. Habitat is available for an estimated 600 mountain goats in the Wallowa Mountains. Mountain goats offer extremely limited hunting opportunities in the subbasin; one tag was issued for the area in 2000 and Oregon law allows hunters to hold only one mountain goat tag in a lifetime. Mountain goat management in the subbasin is guided by Oregon’s Interim Mountain Goat Management Plan (ODFW 2000b), (Nowak 2001).
Long-eared owls in the area most commonly nest in dwarf mistletoe brooms in Douglas fir-forest. Gophers voles and deer mice are the predominant prey, at least during nesting season. Populations in the region appear to be stable (Wallowa-Whitman National Forest 1999)
Gray wolf and Grizzly bear
Two additional species, the gray wolf (Canis lupus) and the grizzly bear (Ursus arctos), in these families historically occurred in the subbasin but have been extirpated (Wallowa-Whitman National Forest 1995).
Forests, Woodland, and Sagebrush; Forests, Woodland and montane shrub
Over a dozen species inhabiting the subbasin belong to these families. They include the rufous hummingbird (Selasphorus rufus), broad-tailed hummingbird (Selasphorus platycercus), black-chinned hummingbird (Archilochus alexandri), pine siskin (Carduelis pinus), northern goshawk during the winter, yuma myotis (Myotis yumanensis), long-eared myotis (Myotis evotis), fringed myotis (Myotis thysanodes), long-legged myotis (Myotis volans), Townsend’s big-eared bat (Corynorhinus townsendii), western small-footed myotis (Myotis ciliolabrum), spotted bat (Euderma maculatum), and pallid bat (Antrozous pallidus).
Townsend’ big-eared bat
Townsend’s big-eared bat, like many of the species in this family, can inhabit a variety of macrohabitats such as forests, woodlands or shrublands but requires specific components within these general habitat types (Wallowa-Whitman National Forest 1998). Specific habitat components needed for breeding, roosting, and resting include tunnels, caves, crevices, talus, and abandoned buildings (Wallowa-Whitman National Forest 1998). Townsend’s big-eared bats are year round residents of the Imnaha subbasin which contains nursery, foraging and hibernating habitat (Wallowa-Whitman National Forest 1998). Populations of Townsend’s big-eared bats are thought to be decreasing in the subbasin and across the western United States; they are listed as a USFWS species of concern, and as sensitive or canidate in Oregon, Washington and Idaho. One of six significant maternity colonies of Townsend’s big-eared bats documented to occur in Oregon lies entirely within the HCNRA (Wallowa-Whitman National Forest 1999).
The spotted bat has specific habitat components similar to Townsend’s big-eared bat. The spotted bat uses specific components such as caves, talus, cliffs, and rimrock within broader grassland, shrubland, or riparian habitats (Wallowa-Whitman National Forest 1998). Population trend and size information is not known for this species within the Imnaha (Wallowa-Whitman National Forest 1998).
Rangeland Mosaic Dependent Species
Seven Rangeland Mosaic Dependent family members inhabit the subbasin and belong to the rangeland mosaic dependent family (2000a). One mammal, Preble’s shrew (Sorex preblei), and six birds, ferruginous hawk (Buteo regalis), burrowing owl (Athene cunicularia), short-eared owl (Asio flammeus), vesper sparrow (Pooecetes gramineus), lark sparrow (Chondestes grammacus), and western meadowlark (Sturnella neglecta), make up this family. Ferruginous hawks, short-eared owls, burrowing owls, western meadowlarks, and vesper sparrows are all highly associated with non-forested habitats, particularly mosaics of rangeland community types (Wallowa-Whitman National Forest 1998).
Six occurrences of ferruginous hawks in the subbasin have been reported to the Oregon Natural Heritage Program. In the Big Sheep Creek watershed portion of the subbasin, ferruginous hawks nest primarily on private lands (Wallowa-Whitman National Forest 1995). Population status information shows a downward trend for ferruginous hawks (Wallowa-Whitman National Forest 1995).
Sagebrush and Grassland Dependent Species
One mammal, sagebrush vole (Lemmiscus curtatus), and six bird species, sage thrasher (Oreoscoptes montanus), Brewer’s sparrow (Spizella breweri), sage sparrow (Amphispiza belli), loggerhead shrike (Lanius ludovicianus), Columbian sharp-tailed grouse (Tympanuchus phasianellus columbianus), and grasshopper sparrow (Ammodramus savannarum), are species recognized by Wisdom et al. as sagebrush or grassland dependent.
Columbian sharp-tailed grouse
The subspecies Columbian sharp-tailed grouse was extirpated from the state of Oregon in the 1960s, but has since been reintroduced (The Nature Conservancy 2000a; The Nature Conservancy 2000b; Wallowa-Whitman National Forest 1995). The dramatic declines in the sharp-tailed grouse populations experienced in the late 1800s and early 1900s are attributed to overharvest, overgrazing, conversion of bunchgrass habitats to agriculture, and human disturbance of breeding populations (Crawford and Coggins 2000). Three reintroductions of sharp-tailed grouse occurred along Clear Lake Ridge south of Little Sheep Creek between 1991 and 1993; resulting in the releas of 86 grouse into the subbasin(Crawford and Coggins 2000). Columbian sharp-tailed grouse have also been reintroduced to the subbasin on The Nature Conservancy’s Zumwalt Prairie Reserve (The Nature Conservancy 2000b).
Brewer’s sparrow and loggerhead shrike are a neotropical migrants that occur in the subbasin during selected portions of the year. Both have exhibited declining population trends throughout their ranges (Wallowa-Whitman National Forest 1998).
Habitat generalist species
Many species in the subbasin utilize a number of different habitat types and can be considered habitat generalists. Many of these are important game species whose populations are managed by the wildlife biologists in the subbasin including elk, mule deer, and black bear.
Elk require a mosaic of early forage-producing stages and later cover-forming stages of forest development; both in close proximity. Management of elk in eastern Oregon is guided by the Rocky Mountain Elk Plan (Oregon Department of Fish and Wildlife 1992b). The plan was developed through a public review process and identifies acceptable population numbers and management options for each big game management unit. Big game management units all or partially contained by the Imnaha subbasin include Chesnimnus, Minam, Snake River, and Imnaha, these units are within the Wallowa district. Elk populations in the Wallowa district met or exceeded the Management Objective of 17,050 for most of the 1980s. Since 1990 Elk populations have declined; an estimated elk population of 11,800 was reported for the Wallowa district in 2001 (Oregon Department of Fish and Wildlife Oregon Department of Fish and Wildlife unpublished data). Potential factors in this decline include, poor calf survival, large predator populations, and the spread of noxious weeds on elk range. In the last three years ODFW has spent an estimated $20,000 on habitat improvements in the lower Imnaha subbasin. These projects were done in collaboration with private landowners and include weed control, seedings, fertilizing burnings and water developments (Oregon Department of Fish and Wildlife unpublished data). The majority of the elk range in the subbasin is publicly owned and damage reports are rare. The number of hunting tags issued in the area has declined by 5,000 tags in recent years, yet elk hunting opportunities remain good (Nowak 2001).
Rocky Mountain mule deer
Rocky mountain mule deer occupy a wide range of habitat types including desert shrub, woodland and conifer forest. They inhabit higher elevation areas in the summer and migrate to the lower elevation areas of the subbasin to escape deep snows in winter. Mule deer population estimates for the Wallowa district have been below the ODFW management objective of 26,800 for many years. Mule deer populations in the area have trended upwards for the last five years from a low of 17,400 in 1996 to 20,000 in 2001 (Oregon Department of Fish and Wildlife unpublished data). Unmanaged livestock grazing, encroachment of human development, invasion of noxious weeds and loss of riparian vegetation have adversely affected habitat quality and quantity on winter ranges (Nowack et al 2001). Management strategies regarding mule deer were developed through a public review process and are identified in the Mule Deer Plan (Oregon Department of Fish and Wildlife 1990a).
The black bear is an indicator of ecosystem health (Oregon Department of Fish and Wildlife 1993a) and among the nine species determined by Cederholm et al. (2000) to have a strong consistent link to salmon. Partially as a result of recent restrictions on the use of bait and hounds when hunting bears population in the region have increased. Black bears management in the subbasin is guided by the Black Bear Management Plan (Oregon Department of Fish and Wildlife 1993a). High levels of bear predation on elk calves may be a factor in poor calf recruitment rates (Oregon Department of Fish and Wildlife 1993a).