Endangered and Threatened Wildlife and Plants; 90-day Finding on a Petition To List the Western Sage Grouse

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of 90-day petition finding.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce a 90-day finding on a petition to list the western sage grouse (Centrocercus urophasianus phaios) under the Endangered Species Act of 1973, as amended. We find that the petition does not present substantial scientific or commercial information indicating that listing this subspecies may be warranted, on the basis of our determination that there is insufficient evidence to indicate that the western population of sage grouse is a valid subspecies or a Distinct Population Segment (DPS). We will not be initiating a further status review in response to this petition. We ask the public to submit to us any new information that becomes available concerning the status of or threats to the western population of sage grouse. This information will help us monitor and encourage the conservation of this species.

DATES:

The finding announced in this document was made on January 26, 2003. You may submit new information concerning this species for our consideration at any time.

ADDRESSES:

The complete file for this finding is available for inspection, by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Oregon Fish and Wildlife Office, 2600 SE. 98th Avenue, Suite 100, Portland, Oregon 97266. Submit new information or comments concerning this petition to the Service at the above address.

FOR FURTHER INFORMATION CONTACT:

Kemper M. McMaster, Field Supervisor, Oregon Fish and Wildlife Office (see ADDRESSES section) (telephone 503/231-6179; facsimile 503/231-6195).

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(A) of the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.), requires that we make a finding on whether a petition to list, delist, U.S.C. 1531 et seq.), requires that we make a finding on whether a petition to list, delist, or reclassify a species presents substantial scientific or commercial information indicating that the petitioned action may be warranted. We are to base this finding on all information available to us at the time we make the finding. To the maximum extent practicable, we must make this finding within 90 days of our receipt of the petition, and publish the notice of the finding promptly in the Federal Register. Our standard for substantial information within the Code of Federal Regulations (CFR) with regard to a 90-day petition finding is “that amount of information that would lead a reasonable person to believe that the measure proposed in the petition may be warranted” (50 CFR 424.14(b)). If the finding is that substantial information was presented, we are required to promptly commence a review of the status of the involved species, if one has not already been initiated, under our internal candidate assessment process.

We received a petition, dated January 24, 2002, from the Institute for Wildlife Protection requesting that the western sage grouse (Centrocercus urophasianus phaios) occurring from northern California, through Oregon and Washington, in addition to any western sage grouse that still occur in parts of Idaho, be listed under the Act. Although we published a 12-month finding for the Columbia Basin distinct population segment (DPS) of sage grouse in May 2001, the petitioner requested that we include this population in our review of the petition. The 12-month finding for the Columbia Basin DPS of sage grouse was that listing was warranted but precluded due to higher priority listing actions (66 FR 22984). That finding presented information describing genetic and ecological differences between sage grouse located in the Columbia Basin and the population of sage grouse in central and southern Oregon, as well as the significant gap in the range of the Washington population (66 FR 22984). The Columbia Basin DPS of sage grouse is presently a candidate for listing (67 FR 40657). Since our 12-month finding presented an in-depth review of this population of sage grouse, this review will only focus on the remaining portion of the petitioned sage grouse.

The petitioner requested that the western sage grouse occurring in northern California, in addition to any western sage grouse that still occur in parts of Idaho, be listed under the Act. However, we note that the inclusion of California is incorrect according to Aldrich and Duvall (1955) and Aldrich (1963). Sage grouse in northern California and northwestern Nevada were reclassified as an intermediate form (Aldrich and Duvall 1955; Aldrich 1963). As for any western sage grouse in Idaho, Aldrich (1946) stated that it was possible that western sage grouse occurred in central-western Idaho. However, no specimens have ever been collected to verify the existence of western sage grouse in Idaho.

The petition clearly identified itself as such and contained the name, address, and signature of the petitioning organization's representative. Accompanying the petition was information related to the taxonomy, life history, demographics, movements, habitats, threats, and the past and present distribution of the western sage grouse. The petitioner contends that the range of the western sage grouse and the number of individuals, have decreased by approximately half, and that the subspecies has become isolated into a series of fragments. In order to determine if substantial information is available to indicate that the petitioned action may be warranted, we have reviewed the subject petition, literature cited in the petition, information provided by recognized experts or agencies cited in the petition, and information otherwise available in Service files.

This 90-day petition finding is made in accordance with a proposed settlement agreement which would require us to complete a finding by January 30, 2003 (Institute for Wildlife Protection and Dr. Steven G. Herman v. Norton et al. (CV02 1604L, W.D. WA)).

The following information regarding the description and natural history of greater sage grouse (Centrocercus urophasianus) (sage grouse) (American Ornithological Union (AOU) 2000) has been condensed from these sources: Aldrich 1963; Johnsgard 1973; Connelly et al. 1988; Connelly et al. 2000; Fischer et al. 1993; Drut 1994; Western States Sage Grouse Technical Committee 1996 and 1998; and Schroeder et al. 1999.

The sage grouse is the largest North American grouse species. Adult males range in size from 66 to 76 centimeters (cm) (26 to 30 inches (in)) and weigh between 2 and 3 kilograms (kg) (4 and 7 pounds (lb)); adult females range in size from 48 to 58 cm (19 to 23 in) and weigh between 1 and 2 kg (2 and 4 lb). Males and females have dark grayish-brown body plumage with many small gray and white speckles, fleshy yellow combs over the eyes, long pointed tails, and dark green toes. Males also have blackish chin and throat feathers, conspicuous phylloplumes (specialized erectile feathers) at the back of the head and neck, and white feathers forming a ruff around the neck and upper belly. During breeding displays, males also exhibit olive-green apteria (fleshy bare patches of skin) on their breasts.

Sage grouse depend on a variety of shrub steppe habitats throughout their life cycle, and are particularly tied to several species of sagebrush (Artemesia spp.). Throughout much of the year, adult sage grouse rely on sagebrush to provide roosting cover and food. During the winter, they depend almost exclusively on sagebrush for food. The type and condition of shrub steppe plant communities strongly affect habitat use by sage grouse populations. However, these populations also exhibit strong site fidelity (loyalty to a particular area). Sage grouse may disperse up to 160 kilometers (km) (100 miles (mi)) between seasonal use areas; however, average population movements are generally less than 34 km (21 mi). Sage grouse are also capable of dispersing over areas of unsuitable habitat.

During the spring breeding season, primarily during the morning hours just after dawn, male sage grouse gather together and perform courtship displays on areas called leks (areas where animals assemble and perform courtship displays). Areas of bare soil, short grass steppe, windswept ridges, exposed knolls, or other relatively open sites may serve as leks. Leks range in size from less than 0.4 hectare (ha) (1 acre (ac)) to over 40 ha (100 ac) and can host from several to hundreds of males. Some leks are used for many years. These “historic” leks are typically larger than, and often surrounded by, smaller “satellite” leks, which may be less stable in size and location within the course of 1 year and between 2 or more years. A group of leks where males and females may interact within a breeding season or between years is called a lek complex. Males defend individual territories within leks and perform elaborate displays with their specialized plumage and vocalizations to attract females for mating.

Females may travel up to 35 km (22 mi) after mating, and typically select nest sites under sagebrush cover, although other shrub or bunchgrass species are sometimes used. Nests are relatively simple and consist of scrapes on the ground. Clutch sizes range from 6 to 13 eggs. Nest success ranges from 10 to 63 percent and is relatively low compared to other prairie grouse species. Shrub canopy and grass cover provide concealment for sage grouse nests and young, and may be critical for reproductive success.

Sage grouse typically live between 1 and 4 years; however, sage grouse up to 10 years of age have been recorded in the wild. The annual mortality rate for sage grouse is roughly 50 to 55 percent, which is relatively low compared to other prairie grouse species. Females generally have a higher survival rate than males, which accounts for a female-biased sex ratio in adult birds.

Prior to European expansion into western North America, sage grouse were believed to occur in the States of Washington, Oregon, California, Nevada, Idaho, Montana, Wyoming, Colorado, Utah, South Dakota, North Dakota, Kansas, Oklahoma, Nebraska, New Mexico, Arizona, and the Canadian provinces of British Columbia, Alberta, and Saskatchewan (Schroeder et al. 1999). Currently, sage grouse occur in 11 states and 2 Canadian provinces, ranging from extreme southeastern Alberta and southwestern Saskatchewan, south to western Colorado, and west to eastern California, Oregon, and Washington. In addition, sage grouse occur in southern Idaho, the northern two-thirds of Nevada, parts of Utah, most of Wyoming, southern and eastern Montana, and extreme western North and South Dakota. Sage grouse have been extirpated from Nebraska, Kansas, Oklahoma, New Mexico, Arizona, and British Columbia (Schroeder et al. 1999).

The distribution of sage grouse has contracted in a number of areas, most notably along the northern and northwestern periphery and in the center of their historic range. There may have been between roughly 1.6 million and 16 million sage grouse rangewide prior to European expansion across western North America (65 FR 51578). The Western States Sage Grouse Technical Committee (WSSGTC) (1999) estimated that there may have been about 1.1 million birds in 1800. Braun (1998) estimated that the 1998 rangewide spring population numbered about 157,000 sage grouse. More recent estimates put the number of sage grouse rangewide at between roughly 100,000 and 500,000 birds (65 FR 51578). Sage grouse population levels may have declined from historic to recent times between 69 and 99 percent (65 FR 51578). WSSGTC (1999) estimates the decline between historic and present day to have been about 86 percent.

Apparently, much of the overall decline in sage grouse populations occurred from the late 1800s to the mid-1900s (Hornaday 1916; Crawford 1982; Drut 1994; Washington Department of Fish and Wildlife (WDFW) 1995; Braun 1998; Schroeder et al. 1999). Other declines in sage grouse populations apparently occurred in the 1920s and 1930s, and then again in the 1960s and 1970s (Connelly and Braun 1997).

In Oregon, a 50 percent net loss in sage grouse distribution took place between about 1900 and the mid-1950s (Drut 1994). Since the 1950s, sage grouse distribution in Oregon has undergone only minor changes (Drut 1994). Between 1941 and 1952, hundreds of birds from Harney and Malheur counties were transplanted to Crook, Sherman, Wasco, and other counties (Crawford 1982). These transplants were not successful, and it is unclear what effect a successful translocation of sage grouse from the eastern population into the western population might have had on the genetics of sage grouse in Oregon.

Two subpopulations of sage grouse remain in Washington (WSGWG 1998). One occurs primarily on private and State-owned lands in Douglas County; the other occurs at the Yakima Training Center, administered by the U.S. Army in Kittitas and Yakima counties. These two subpopulations are isolated from the Oregon population and nearly isolated from one another (65 FR 51578).

Western sage grouse were first described in 1946 by Aldrich. Aldrich (1946) examined 11 specimens collected in Washington (3), Oregon (7), and California (1), and on the basis of slight color differences in the plumage, concluded that a subspecies existed in the western portion of the greater sage grouse range. The distribution of the western sage grouse was described as occurring from north to central-southern British Columbia; west to central Washington, central Oregon, and northeastern California; south to northeastern California; east to southeast-central and northeastern Oregon (possibly central-western Idaho) and central-eastern Washington (Aldrich 1946). Later, the distribution was modified to reclassify sage grouse in northwestern Nevada and northern California as an intermediate form (Aldrich and Duvall 1955; AOU 1957; Aldrich 1963). The validity of the taxonomic separation between an eastern and a western subspecies has since been questioned (Johnsgard 1983; Johnsgard 2002; Benedict et al. in press).

In 1957, the AOU recognized a subspecies division within the sage grouse taxon. Since that time, however, it has not conducted a review of this subspecies distinction. The AOU stopped listing subspecies as of the 6th (1983) edition of its Checklist, although it recommended the continued use of the 5th edition for taxonomy at the subspecific level. The AOU has not formally or officially reviewed the subspecific treatment of most North American birds, although it is working towards that (Richard C. Banks, National Museum of Natural History, pers. comm., 2000, 2002). Therefore, the western and eastern subspecies of sage grouse are still recognized by the AOU. However, the Oregon Department of Fish and Wildlife and others do not agree with this subspecies designation (Drut 1994).

R. Banks of the National Museum of Natural History (in litt., 1992) reviewed the same sage grouse specimens available to Aldrich in 1946 and concluded that there is only a weak basis for the separation into two subspecies. Braun stated that the so-called western race of sage grouse in Oregon and Washington does not differ from sage grouse in California, northern Colorado, Wyoming, and other States (Clait E. Braun, Colorado Division of Wildlife, in litt. 1992 cited in Drut 1994). Braun continued by stating that the inclusion of western sage grouse as a category 2 species/subspecies by the Service is without merit.

In 1990, protein and deoxyribonucleic acid (DNA) studies were initiated to clarify the status of sage grouse subspecies in Oregon. Preliminary results indicated no differentiation among birds collected from different areas (Drut 1994). However, because the sample size was small, these results were never published (M. Pope, Oregon State University, pers. comm., 2002). Benedict et al. (in press) recently collected 332 birds from 16 populations in Washington, Oregon, California, and Nevada to sequence a rapidly evolving portion of the mitochondrial control region. They collected samples from either side of the proposed boundary between the western and eastern subspecies, but found no genetic evidence to support the delineation of subspecies (Benedict et al. in press).

The boundary between the western and eastern subspecies is generally considered to occur along a line starting on the Oregon-Nevada border south of Hart Mountain National Wildlife Refuge and ending near Nyssa, Oregon (Aldrich and Duvall 1955; Aldrich 1963). No study has been published depicting a more precise separation between the two previously recognized subspecies. Although no study has specifically been conducted to show movement along this separation boundary, other studies involving radio-tagged sage grouse have documented movements back and forth across the proposed boundary. For example, Crawford and Gregg (2001) noted that two radio-tagged sage grouse hens captured on Hart Mountain National Wildlife Refuge in south-central Oregon moved to the vicinity of Lone Grave Butte on the Beatys Butte study area southeast of the refuge. They also noted that a hen and week-old brood moved from Beatys Butte to the Catnip Reservoir area of Sheldon National Wildlife Refuge in Nevada, a distance of over 32 km (20 mi). By mid-summer, 25 percent of marked hens (6) still alive had moved south onto Sheldon National Wildlife Refuge (Crawford and Gregg 2001). This small sample demonstrates movement of sage grouse across the boundary area separating the western and eastern populations of sage grouse.

At this time, sage grouse experts disagree about whether the western sage grouse is a valid subspecies. When informed taxonomic opinion is not unanimous, we evaluate the available published and unpublished information to come to our own adequately documented conclusion regarding the validity of taxa. Although the AOU has not made a procedural change regarding the treatment of subspecies, the best available science tells us that there is no genetic distinction between western and eastern sage grouse. Therefore, on the basis of lack of distinct genetic differences between the two putative subspecies, lack of ecological or physical factors that might contribute to population isolation, and evidence that birds freely cross the supposed boundary zone between the subspecies, we conclude that the western sage grouse is not a valid subspecies of the greater sage grouse. Because we no longer consider the western sage grouse a valid taxon, we must then consider whether the petitioned sage grouse populations might constitute a DPS.

Under our DPS policy (61 FR 4722), we use three elements to assess whether a population under consideration for listing may be recognized as a DPS: (1) A population segment's discreteness from the remainder of the taxon; (2) the population segment's significance to the taxon to which it belongs; and (3) “[t]he population segment's conservation status in relation to the Act's standards for listing (i.e., is the population segment, when treated as if it were a species, endangered or threatened?).” If we determine that a population being considered for listing may represent a DPS, then the level of threat to the population is evaluated based on the five listing factors established by the Act to determine if listing it as either threatened or endangered may be warranted.

A population segment of a vertebrate species may be considered discrete if it satisfies either of the following conditions. The first condition is whether the species' population is markedly separated, or isolated, from other populations of the same taxon “as a consequence of physical, physiological, ecological, or behavioral factors.” When evaluating these four factors, “[q]uantitative measures of genetic or morphological discontinuity may provide evidence of this separation.” The second condition, which does not apply here, is whether the population segment be “delimited by international governmental boundaries within which differences in control of exploitation, management of habitat, conservation status, or regulatory mechanisms exist that are significant in light of section 4(a)(1)(D) of the Act.”

In determining the discreteness, or isolation, of the petitioned sage grouse, one of the factors to consider is physical separation from the rest of the taxon. The petitioner did not provide substantial information to demonstrate, nor does information in our files indicate, that the western population of sage grouse are physically isolated from nearby eastern populations. Along the eastern boundary of the petitioned sage grouse, the landscape consists of various mountain ranges, intervening valleys, and canyons, and birds are able to move between these areas. No physical barriers exist that would preclude the movement of birds across this landscape and hypothetical boundary separating the petitioned and more easterly populations. Crawford and Gregg (2001), through their studies, have documented the movement of sage grouse across this boundary. Dispersing birds have been estimated to be able to disperse up to 160 km (100 mi) (WDFW 1995; Schroeder et al. 1999). The petitioner acknowledges in the petition that the ranges of western and eastern populations of sage grouse overlap in Oregon (Webb 2001).

Other factors to consider with regard to discreteness or isolation of a population are genetic, morphological, and behavioral differences. As discussed above, there does not appear to be any genetic differentiation between sage grouse individuals found in western and eastern populations. Individual morphological variation, such as color, in this [sage] grouse, as in other species, is extensive (R. Banks, in litt., 1992). Banks (in litt., 1992) doubts that the color difference noted by Aldrich is sufficient to warrant the description or recognition of a subspecies, with the present concepts. He continues by stating that most taxonomists today would not make the decision to name a population on the basis of the minor color variation shown in the small sample available here. Even Aldrich (in litt., 1992 cited in Drut 1994) states that the amount of morphological difference required to name a distinct population as a subspecies is arbitrary. The petitioner does not provide any information to document that the petitioned sage grouse exhibits any unique behavioral traits.

In summary, to make a DPS determination, we examined physical, physiological, ecological, and behavioral factors. Since no international government boundaries of significance are involved, this condition for a finding of discreteness was not considered in reaching this determination. Neither the information presented in the petition nor that available in Service files presents substantial scientific or commercial information to demonstrate that the western population of sage grouse is discrete from the remainder of the taxon. Accordingly, we are unable to define a listable entity of the western population of sage grouse within the greater sage grouse taxon. Therefore, we did not address the second element for determining a DPS, which is the potential significance of the western population of sage grouse to the remainder of the taxon. Finally, since the western population of sage grouse cannot be defined as a DPS at this time, we did not evaluate its status as endangered or threatened on the basis of either the Act's definitions of those terms or the factors in section 4(a) of the Act.

Petition Finding

We have reviewed the petition, literature cited in the petition, other pertinent literature, and information available in Service files. After our review, we find the petition does not present substantial information to indicate that the petitioned action may be warranted. We base this finding on a lack of evidence to support a separation of the greater sage grouse into eastern and western subspecies, and also on our determination that the western population of sage grouse does not constitute a DPS on the basis of the following: (a) insufficient information to determine whether the western population of sage grouse is geographically separated from other sage grouse throughout the range of the taxon; and (b) insufficient information to demonstrate that genetic, morphological, and behavioral aspects of the western population of sage grouse are unique.

References Cited

A complete list of all references cited herein is available upon request from the Oregon Fish and Wildlife Office (see ADDRESSES section).

Author

The primary author of this notice is Jeff Dillon, U.S. Fish and Wildlife Service, Oregon Fish and Wildlife Office (see ADDRESSES section).

Authority: The authority for this action is the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).