U.S. FISH AND WILDLIFE SERVICE SPECIES ASSESSMENT AND LISTING PRIORITY ASSIGNMENT FORM

SCIENTIFIC NAME: Polites mardon

COMMON NAME: Mardon skipper

LEAD REGION: Region 1

INFORMATION CURRENT AS OF: April 2007

STATUS/ACTION

Species assessment ___ New candidate _X_ Continuing candidate ___ Non-petitioned _X_ Petitioned - Date petition received: 12/11/02 90-day positive - FR date: 12-month warranted but precluded - FR date: Did the petition request a reclassification of a listed species?

FOR PETITIONED CANDIDATE SPECIES: a. Is listing warranted (if yes, see summary of threats below) YES b. To date, has publication of a proposal to list been precluded by other higher priority listing actions? YES c. If the answer to a. and b. is yes, provide an explanation of why the action is precluded. We find that the immediate issuance of a proposed rule and timely promulgation of a final rule for this species has been, for the preceding 12 months, and continues to be, precluded by higher priority listing actions (including candidate species with lower LPNs). During the past 12 months, almost our entire national listing budget has been consumed by work on various listing actions to comply with court orders and court- approved settlement agreements, meeting statutory deadlines for petition findings or listing determinations, emergency listing evaluations and determinations, and essential litigation-related, administrative, and program management tasks. We will continue to monitor the status of this species as new information becomes available. This review will determine if a change in status is warranted, including the need to make prompt use of emergency listing procedures. For information on listing actions taken over the past 12 months, see the discussion of “Progress on Revising the Lists,” in the current CNOR which can be viewed on our Internet website (http://endangered.fws.gov/).

___ Listing priority change Former LP: ___ New LP: ___ 1 Latest Date species became a Candidate: 10/25/99 NA Candidate removal: Former LP: ______A - Taxon is more abundant or widespread than previously believed or not subject to the degree of threats sufficient to warrant issuance of a proposed listing or continuance of candidate status. ___ F - Range is no longer a U.S. territory. I - Insufficient information exists on biological vulnerability and threats to support listing. ___ M - Taxon mistakenly included in past notice of review. ___ N - Taxon may not meet the Act’s definition of “species.” ___ X - Taxon believed to be extinct.

ANIMAL/PLANT GROUP AND FAMILY: Insect; Hesperiidae (Skippers)

HISTORICAL STATES/TERRITORIES/COUNTRIES OF OCCURRENCE: Washington, Oregon, and California

CURRENT STATES/ COUNTIES/TERRITORIES/COUNTRIES OF OCCURRENCE: Washington, Oregon, and California

LAND OWNERSHIP: Most of the sites occur on Federal lands, however, State, Tribal, and private lands also have occurrences. In the following states, land ownership includes:

Washington: Department of Defense (Fort Lewis Army Installation) (5%), Washington Department of Fish and Wildlife (5%), Yakama Indian Reservation (1%), private (1%), USDA Forest Service (53%).

Oregon: USDA Forest Service, Bureau of Land Management (23%), and private ownership (2%).

California: Redwood National Park (5%), USDA Forest Service Six Rivers National Forest (5%).

LEAD REGION CONTACT: Scott McCarthy (503/231-6131), [email protected].

LEAD FIELD OFFICE CONTACT: Western Washington Fish and Wildlife Office, Ted Thomas (360/753-4327)

BIOLOGICAL INFORMATION:

Species Description

The Mardon skipper (Polites mardon) is a small, nonmigratory butterfly that was first described by W. H. Edwards (1881) (Pyle 2002, Black et al. 2002). This tawny-orange butterfly has a stout, hairy body. Less than 1 inch across, the Mardon skipper is more compact, with shorter, rounder wings than other skippers (Pyle 2002). The upper surfaces of the wings are orange with broad dark borders. The lower surfaces are light tan orange, with a distinctive pattern of light yellow to white rectangular spots (Potter et al. 1999). 2 Taxonomy

The original description of the species was made by Edwards in 1881. The type specimens of Polites mardon were based on three males and three females taken from grasslands near Tenino, Washington by H.K. Morrison in 1880. The subspecies P. mardon klamathensis was named from specimens collected near the current Soda Mountain sites in Jackson County, WA (Mattoon et.al 1998). Only the butterflies known from southern Oregon are of the subspecies P. m. klamathensis.

Habitat /Life History

The Mardon skipper spends its entire life cycle in one location; it does not migrate. Dispersal distance is unknown, but because the species is nonmigratory it is believed to be limited. Runquist (2004) reported observing Mardon skipper dispersing up to 1.6 km, which may restrict the species ability to move between habitat patches and their host food plants. After mating, females deposit their eggs (oviposit) into tufts of bunchgrass (Festuca roemeri, F. idohaensis, or F. rubra)(Ann Potter, Washington Department of Fish and Wildlife (WDFW), pers. comm. 2003; USFS 2006; Beyer and Black 2007) and California oatgrass (Danthonia californica) and sedge (Carex spp) (Beyer and Black 2007). Eggs hatch after 6 or 7 days (Newcomer 1966; Black et al. 2002). Larvae feed on fescue and oatgrass for approximately 3 months (Dornfeld 1980; Black et al. 2002; Pyle 2002). Pupae hibernate through winter, loosely cocooned in the grass and thatch (Newcomer 1966; Pyle, 2002).

In the South Puget Sound Region of Washinton, Mardon skippers are found in open, glacial outwash grasslands with abundant Festuca roemeri interspersed with Viola adunca (Potter et al. 1999; Black et al. 2002) on the remnant prairies. On these prairies, adults feed on nectar from a variety of herbaceous plants (Black et al. 2002; Beyer and Black 2007), although they prefer the early blue violet (Viola adunca) (Pyle 2002). The Early blue violet and common vetch (Vicia sativa) were strongly preferred as nectar sources, and Scot=s broom (Cytisus scoparius) was strongly avoided (Hays et al. 2000; Black et al. 2002). Nectaring has also been observed on common camas (Camassia quamash), prairie lupine (Lupinus lepidus), fine-leaved desert parsley (Lomatium utriculatum), western buttercup (Ranunculus occidentalis), sea blush (Plectritis congesta) and yarrow (Achillea millefolium).

In the southern Cascades of Washington, the Mardon skipper is found in open grasslands within ponderosa pine (Pinus ponderosa) savanna/woodland or at higher elevations ranging from 549 to 1,677 meters (m) (1,800 to 5,500 feet (ft)) in the grand fir (Abies grandis) zone (Harke 2001; Potter and Fleckenstein 2002). This forest types span from the Mt Adams Ranger District of the Gifford Pinchot National Forest to the Naches Ranger District on Wenatchee National Forest, where a small population of Mardon skipper was detected in 2006.

In the southern Cascades of Washington, adults have frequently been observed nectaring on vetch (Vicia spp.), penstemon (Penstemon procerus), and sego lily (Calochortus spp.) (Potter and Fleckenstein 2002, ). Wallflower (Erysimum capitatum, E. asperum), hawkweed (Hieracium 3 sp.), hawksbeard (Crepis sp.), geranium (Geranium sp.), fleabane (Erigeron perigrinus), strawberry (Fragaria spp).) and yarrow (Achillea millefolium) are also reported nectar sources from this region (Newcomer 1966; Harke 2001; Potter and Fleckenstein 2002; Beyer and Black 2007).

The Mardon skipper detection sites in the southern Cascade of Washington vary in size from small 0.25 hectare (ha) (0.5 acre (ac)) or less meadows to large grassland complexes. Site conditions range from dry, open ridgetops to grasslands associated with wetlands, springs, or riparian habitat. Sites with grassland vegetation, including grassy forest openings, roadside meadows in dry forest buffers, and grass-dominated tree plantations may support Mardon skipper populations.

Populations in southern Oregon occupy small (less than 0.25B4 ha (0.5B10 ac)) high-elevation (1,372B1,555 m (4,500B5,100 ft)) grassy meadows within mixed conifer forests. The habitat features where Mardon skipper are found are dominated by fescue grasslands and the primary nectar plants being utilized are cinquefoil (Potentilla), butterweed (Senecio) and self-heal (Prunella) (Ross 2007). The habitat for Mardon skipper in southwestern Oregon and northern California have been historically subjected to frequent low-intensity fires (Agee 1994), which played an important role in maintaining the grassland plant communities free from trees.

The California populations are located on serpentine balds dominated by Festuca idahoensis in sparse Jeffery Pine forests. Common nectar plants include Phlox, Potentilla, Viola, and Castilleja (Runquist 2004). The four principal grasslands of this historic population cover an area of less than 2 hectares (4.5 acres). A new population was discovered in 2004 on Little Bald Hill in Redwood National Park more than 10 km distance from the original population (G. Falxa, FWS, Arcata, CA pers. comm. 2006). This distance appears to be well beyond the dispersal distance of a sedentary, nonmigratory butterfly like the Mardon skipper (Pyle, 2002).

Historical Range/Distribution

The Mardon skipper is a northwestern butterfly with a remarkably disjunct range. No estimates of abundance are available from any site prior to 1980. It is likely that Mardon skipper were more widespread prior to widespread contraction of grassland habitat in the past century. (Noss et al 1997; Kruckeberg 1991; Agee 1993). The species historic (post 1980s) and current range is known from four widely separated locations: the south Puget Sound region of Washington, the southern Washington Cascades, the Siskiyou Mountains of southern Oregon, and coastal northern California (Black et al. 2002; U.S. Forest Service 2006; Ross 2007).

Current Range/Distribution

The Mardon skipper is known to occur in Washington, Oregon and northern California. In Washington, it has been observed and is regularly surveyed on South Puget Sound Prairies and in the southern Cascades of Washington. In Oregon, the species is known to occur in the southern Cascades of Oregon, and recent negative surveys have been conducted on the Willamette and Mt. Hood National Forests. In northern California, the species is known from two locations, the High Divide area on BLM lands and from coastal grasslands within Redwood National Park. 4 Surveys generally follow an accepted method for detecting butterflies. Surveys follow protocols for Mardon Skipper sampling designed by Runquist (2004), or transect methods designed by Pollard and Yates (1996) or recent protocols developed by WDFW specifically for Mardon skipper (A. Potter, pers. comm., 1997, 2005). A slow and deliberate walk is made through potential and marginal habitat. For each geographic area, the timing of surveys varies, depending on local climates and food plant availability. Butterfly surveys are conducted in appropriate weather conditions (> 55 degrees F.) and preferably during low wind conditions. Surveys on the prairies of south Puget Sound, in southern Oregon Cascades and in northern California begin in late May; surveys in the southern Cascades of Washington usually begin in Mid to late June. Surveys at all locations extend for 4 to 6 weeks. Information collected at each surveyed site included the site name, date, description of the habitat and the results of the surveys, which could be no Mardon skipper detected or the number of individual butterflies counted.

In Washington, the historic range and abundance of Mardon skippers is not well known, and there are no known estimates of abundance prior to 1980 (Black et al. 2002). Mardon skippers are apparently extirpated from five historic sites (four in the south Puget Sound region and one in the southern Cascades) (Potter et al. 1999). Historically, Mardon skippers were known to occur in Thurston, Klickitat, and Yakima Counties. Currently, Mardon skippers occupy sites in Thurston, Pierce, Klickitat, Skamania, and Yakima Counties (Potter et al. 1999).

South Puget Sound Prairie. Systematic searches began for Mardon skipper in 1997. In 1998, 17 individuals were counted on a 100-ha (247-ac site) in Pierce County. In Thurston County, 5B10 adults were detected at one 2 hectare site (5 ac) site and an estimated 50B80 adults were detected a second 10 ha (25 ac) site. No Mardon skippers were found at four of the five historic sites surveyed in 1998 (Potter et al. 1999).

In May and June 2001, two sites, one historic and one current known from Thurston County were surveyed; no Mardon skippers were detected at the 100 hectare site. At the 10 ha site described above, 144 Mardon skippers (highest of 3 counts) were detected. Surveys conducted in 2002 through 2004, detected Mardon skippers at the three known south Puget Sound locations in Thurston and Pierce Counties (A. Potter, pers. comm. 2004). By 2005 Mardon skippers were known from just two populations, one in Pierce County on Fort Lewis and one from a State Wildlife Area in Thurston County. Despite surveys covering more than 2,000 acres, no new populations have been detected on south Puget Sound prairies. (A. Potter pers. comm. 2006; J. Fleckenstein Washington Department of Natural Resources, Pers. comm., 2006; DOD 2007). Recent surveys (2005 and 2006) on Fort Lewis detected Mardon skippers on the periphery of the Artillery Impact Area, with approximately 75 observed in 2005 and more than 100 individuals observed in 2006 (DOD 2007). For Scatter Creek Wildlife Area, (A. Potter 2007) estimated that as many as 30 individuals were detected in 2006 during the peak of the flight season.

Southern Washington Cascades. In 1998, Mardon skippers were found at six of eight sites surveyed. More than 100 adults were estimated to occur at one site, but detections of adult butterflies for the other five sites ranged from 5B50 individuals (Potter et al. 1999). In 2001, surveys for Mardon skippers were intensified and 29 sites were surveyed, Mardon skippers were detected and documented at 13. The number of Mardon skippers observed at occupied sites 5 ranged from less than 5 individuals to more than 180 individuals. All of these sites were located near Mt. Adams in the grand fir zone. A site discovered on the southern slopes of Mt. Adams is located at 1,707 m (5,600 ft), and represents the highest elevation record for the species (Harke 2001). In total, as of 2006, there were 26 known sites in the southern Cascades of Washington, see Table 1.

Prior to 2002, all known sites in the southern Washington Cascades were located east of the Cascade crest. Surveys in 2002 located 10 new sites near Mt. Adams, including 6 sites west of the Cascade crest in the upper Cispus River on the Cowlitz Valley Ranger District, Gifford Pinchot National Forest (GPNF). In 2003, two new locations of Mardon skippers were discovered within the Little White Salmon watershed at the south end of the GPNF by WDFW and U.S. Forest Service staff. In 2004, a new Mardon skipper location was located by WDFW and Yakama Indian Nation personnel, at a location northeast of Mt. Adams near Mt. Adams Lake (V. Harke, U.S. Fish and Wildlife Service (FWS) pers. comm. 2004).

During 2005, two new locations for the Mardon skipper were observed in the southern Washington Cascades. One location was detected at the Conboy Lake National Wildlife Refuge, near Glenwood, Washington and the second location was “Lupine Meadow” on the Cowlitz Valley Ranger District of the GPNF (Harke FWS, 2005; T. Kogut, Wildlife Biologist, Gifford Pinchot National Forest). In 2006, a new location was detected for Mardon skipper on the Wenatchee National Forest, on the Naches Ranger District at the south end of the Wenatchee NF.

As of March 2007, there are 26 known sites where Mardon skipper have been detected in the southern Cascades of Washington. Less than 25% of these populations support populations of greater than 50 individuals, More than 75% of the current population are sparsely populated, usually with fewer than 10 individuals detected during butterfly surveys (A. Potter 2006, V. Harke, pers. comm. 2007). In our review of the Mardon skipper, population patterns appear depressed and disjunct compared with many common, local skippers, including propertius duskywing, silver-spotted skipper, Juba skipper, Sonoran skipper, even Arctic skippers and Two banded Checker skipper, to name a few (Pyle 2002, Audubon Society 1981).

Southern Oregon, During the 2006 field season, the Bureau of Land Management and U.S. Forest Service contracted with Dana Ross, an experienced lepidopterist from Corvallis, OR. Surveys were conducted at 37 distinct sites and Mardon skippers were detected at 16 sites, all within Jackson County. One site was visited in Klamath County during 2005 and 2006, but no Mardon skippers were detected. The area does contain a large wet prairie and apparently suitable habitat with abundant nectar plants and bunchgrass. It is recommended that the site be revisited and surveyed for Mardon skipper (Ross 2007). Of the 16 sites where Mardon skipper were detected three are new discoveries. As with most of the known sites in southern Oregon, the new sites had very few individual Mardon skipper. One site had a total of 7 butterflies and the other two sites revealed just one each. The 16 sites where Mardon skipper were found had a total of approximately 150 individual butterflies, although only 6 of the sites had greater than 10 individual butterflies.

Northern Oregon, Columbia River Gorge. During the 2003 and 2005 field seasons, surveys were conducted on the Mount Hood National Forest on the Oregon side of the Columbia Gorge 6 National Scenic Area. No Mardon skippers were located during any of these surveys. There are no documented occurrences of Mardon skippers in northern Oregon, but the area appears to have suitable grassland habitat for the species (V. Harke, pers. comm. 2007; Mardon skipper Work Group conference call, February 28, 2007)).

Northern California. Mardon skippers were present in 1997, but there were no surveys in 1998. In good years, dozens of individuals are found in the 0.4 to 0.8 ha (1 to 2 ac) core area of High Divide Ridge and along the ridge for 3B5 km (2B3 mi) (Potter et al. 1999; S. Mattoon and K. Hanson, pers. comm. 1998). Surveys were conducted in Del Norte County, northern California in 2003. At that time, just one known Mardon skipper location was present, in the vicinity of the historic High Divide Ridge location, Del Norte County (E. Runquist, pers. comm. 2004). A new location was discovered on Little Bald Hill in Del Norte County, California in late May 2004, in Redwood National Park (R. Hamlin, FWS, pers. comm. 2004, 2007; K. Schmidt, pers. comm., Redwood National and State Park 2007), about ten kilometers from the location on the High Divide Ridge.

No surveys were made at the High Divide Ridge population in 2006 (G. Falxa, FWS, pers. comm.. 2007). The new population within Redwood National and State Park (NSP) was informally surveyed in 2005 and only a few Mardon skippers were detected. During spring of 2006, Redwood NP established transects within an area that was scheduled to be treated with a prescribed burn. During multiple surveys of control and treatment transects no Mardon skippers were detected during 2006, however, on a nearby grassy slope (< one km distance) on Little Bald Hill, fewer than 5 individual Mardon skippers were detected (K. Schmidt 2007).

Table 1. Summary of populations of the Mardon skipper. All surveys were made within the four disjunct geographic areas known for the species and include areas surveyed with negative results Information from USFS Draft Conservation Assessment for Mardon Skipper, July 2006, and Ross 2007. LOCATION Approximate # of POPULATIONS Surveyed with NO As of fall 2006 Observations South Puget Sound 2 Southern Cascades, WA 26 Southern Cascades, OR 24 Northern California 2 meta-populations (4 known pops) Willamette NF X, no butterflies detected Mt. Hood NF X, no butterflies detected

Population Estimates/Status

Estimates of populations for Mardon skipper are difficult to measure. Insect populations vary widely and statistically valid procedures for estimating abundance have not been applied at many locations. It would be difficult to define many of the populations for Mardon skipper as viable populations because the number of individual Mardon skippers estimated for many sites were usually less than 10 individuals. Please see the description of population estimates under the specific geographic areas.

7 DISTINCT POPULATION SEGMENT (DPS) Not applicable to invertebrate species.

THREATS:

A. The present or threatened destruction, modification, or curtailment of its habitat or range.

Because the Mardon skipper is nonmigratory, and thus relatively sedentary, maintaining occupied habitat quality is essential (Erhlich 1992). Pyle (1989) identified the threats to the Mardon skipper as any factor that degrades its obligate grassland habitats, including development, overgrazing, the use of herbicides and pesticides (Bacillus thuringiensis var. kurstaki (Btk)), the encroachment of invasive nonnative and native vegetation, and succession from grassland to forest.

Prairies, which once covered hundreds of thousands of acres of the south Puget Sound region prior to settlement, have been lost to development and conversion to other uses (agriculture and gravel mining). Prairies are threatened by fire suppression, and invasion by native and nonnative plant species. Today, less than 3 percent of the original prairie vegetation remains, and much of this has competing human uses (Crawford and Hall 1997).

Invasion and dominance of nonnative plant species into native grasslands is common and has occurred rapidly at several current and historic Mardon skipper locations. Introduced plants threaten the Mardon skipper by directly competing with larval food plants. Many invasive, nonnative shrubs, forbs, and grasses also prevent or obscure access by adults to nectar plants. Invasive, nonnative, sod-forming grasses (such as Holcus spp. and Arrhenatherum elatius), and weedy forbs, including Hypochaeris radicata, threaten native bunchgrass plant communities (Festuca spp.) that Mardon skippers depend on for egg deposition, larval food, and hibernaculum structures. The short character of Festuca dominated grasslands allows access for the adult butterfly to its similarly short, native nectar sources (Black et al.. 2002). All Mardon skipper sites have not been evaluated for the presence of aggressive, nonnative plants; however, the problem is increasingly common (Potter et al. 1999). Another serious invasive plant threat, Tall oat grass (Arrhenatherum elatius), has spread since 2001 into much of two south Puget Sound locations occupied by Mardon skippers, after the site was mowed to remove Scot’s broom (A. Potter and David Hays, WDFW pers. comm. 2004, 2007).

The invasive shrub, Scot=s broom, poses a threat to grasslands on south Puget Sound prairies and elsewhere because of its ability to form dense stands that exclude native grassland species (Black et al. 2002). Parker et al. (1997) found a nearly exclusive relationship between Scot=s broom and Festuca roemeri. Also, due to its highly flammable nature, areas of Scot=s broom increase the vulnerability of nearby native plants and butterflies, to high-intensity fire. While intensive management appears to be controlling Scot=s broom at two south Puget Sound prairies, this management must be continued for the foreseeable future. Unfortunately, control methods for Scot=s broom, which may include hand pulling, herbicide spraying, tractor mowing, or burning, can negatively impact Mardon skippers. Some Mardon skipper eggs, larvae, or pupae, which are immobile and on ground-level vegetation, may be harmed by trampling or heat (Ehrhardt 1985; Dana 1991).

8 Small, roadside meadows are vulnerable to native species removal and nonnative grass introduction when reseeding occurs after road work. Currently, this threat applies to most southern Oregon and several southern Washington Cascade locations. At least one historic locale in the southern Washington Cascades and a large portion of potential habitat was destroyed by this practice in 1997 or 1998 (Potter et al. 1999).

Human structures, including roads and trails, logging landings, helicopter pads, buildings, towers, livestock corrals, trail destinations, and campgrounds are often built in forest openings. Construction in these areas resulted in direct habitat loss and degradation of remaining habitat. In Washington, roads, trails, and buildings have destroyed habitat at one south Puget South prairie. In the late 1990’s, helicopter landing pads have removed habitat at two southern Washington Cascade locales. A lookout tower, roads, trails, and buildings are also present at one of these sites. Buildings at two additional southern Cascade locales have significantly reduced the size of available habitat. Roads, trails, and camping areas have destroyed habitat at another. Oregon Siskiyou sites are located adjacent to roads in a highly managed landscape. Therefore, it is likely that these structures and associated human activities threaten southern Oregon populations as well (Potter et al. 1999)

Small, isolated populations of sedentary insects, such as the Mardon skipper, are vulnerable to fire (Black et al., 2002). Their grassland habitat persisted partly because of repeated, patchy, low- intensity fires. However, large-scale, high-intensity fires would be detrimental through direct mortality of individuals and damage to habitat because of the continuous, rather than patchy distribution of the burn. Large portions of the Pierce County Mardon skipper site (one of two extant south Puget Sound sites) burned homogeneously in June 2003, (A. Potter pers. comm. 2004). This unseasonably early fire likely killed all Mardon skipper larvae encountered. The site is located on the Fort Lewis Artillery Impact Area where uncontrolled fires regularly occur. However, unusual environmental factors in 2003, including record spring drought and high north winds during the fire’s ignition, combined to create an unusually large and intense spring fire that covered much of the mardon-occupied area.

Recreational activities, including walking, horseback and off-road vehicle use, may directly kill some Mardon skippers by trampling and crushing larvae (Black et al. 2002; U.S. Forest Service 2006). These activities also degrade habitat by damaging native plants and opening ground cover for invasion by weeds. Two occupied south Puget Sound prairies, three southern Washington Cascades sites, and one of the California populations (High Divide) are currently threatened by recreational activities (Potter et al. 1999; U.S. Forest Service 2006).

Livestock grazing may impact Mardon skipper populations through direct trampling of eggs, larvae, pupae, and adults (Black et al. 2002). Larval and adult food sources are destroyed by consumption and trampling by livestock. The native fescue bunch grasses, essential to Mardon skippers, regenerate by seeds that are likely consumed during grazing. Soil disturbance allows invasion by weeds. Grazing has occurred on occupied habitat in the southern Cascades of Washington and was known to have a significant negative impact on one site in the Oregon Siskiyous (Potter et al. 1999). In the south Puget Sound region of Washington, grazing no longer occurs on sites occupied by the Mardon skipper (Potter et al. 1999).

9 Insecticide application poses a threat to populations in the south Puget Sound region and the southern Washington Cascades. The lepidopteran-specific insecticide, Bacillus thurengensis var. kurstaki (Bt or Btk) is applied in large-scale, aerial applications to control Asian gypsy moth (Lymantria dispar) in the Puget Sound region and in the Washington Cascades to control spruce budworm (Choristoneura occidentalis). This insecticide has been proposed for use in the southern Washington and southern Oregon Cascades to control the Douglas-fir tussock moth (Orygia pseudotsugata) (Black et al. 2002). Although grasslands are not targeted for application, small meadow or savanna/woodlands may receive aerial applications due to the hidden location of these small grassland openings within the wooded target area and from drift of the insecticide. Lepidopterans, such as the Mardon skipper, that are single brooded, spring-active species with caterpillars actively feeding during the application period of Btk are especially vulnerable (Wagner and Miller 1995; Black et al. 2002, U.S. Forest Service 2006). Most of the southern Washington Cascade Mardon skipper sites have either recently been treated or are proposed for Bacillus thurengensis var. kurstaki applications by Federal, State, tribal and private land managers (Wagner and Miller 1995; Potter et al. 1999). Herbicide use could damage a population by harming larval or adult food sources. One south Puget Sound population and one Oregon population are especially vulnerable because herbicide applications are used to manage vegetation on electrical utility line right-of-ways crossing these sites.

Most Mardon skipper populations are small enough in numbers and the area they occupy that activities of researchers may pose a threat. Trampling can cause direct mortality to butterflies, and damage to the habitat may lead to additional mortality.

In summary, the primary threats to habitat that are currently active and pose a threat to the Mardon skipper include habitat loss from conversion of land to other uses (agriculture) or development; the invasion of nonnative forbs, shrubs and native trees onto native grasslands; the use of fire and other management activities over large expanses of grasslands or at the wrong time of the year. Grazing is another threat that may alter nectar food plants, trample larvae, and degrade the overall condition of habitat. Much of southern Oregon remains in open range and some of the areas with the Gifford Pinchot National Forest remain in open range and are current active threats. Recreational activities may be a threat at any of the areas where Mardon skipper is found, but it is particularly a threat in areas close to urban centers, such as in the south Puget Sound region of Washington or in southern Oregon Cascades. Herbicide spraying has been a serious threat in the past, however, the use of Btk in areas where Mardon skippers are found has not been an issue of recent concern (in the past two years). Other activities that have been a threat in the past but are no longer;

B. Overutilization for commercial, recreational, scientific, or educational purposes.

Insect collecting is a valuable component of research, including systematic work, and is often necessary for documenting the existence of populations (Black et al. 2002). It is, however, a potential threat to insect populations. Rare butterflies, such as the Mardon skipper, are desirable to collectors. Populations that are small and easily accessible, which is true of most Mardon skipper populations, are especially threatened (Potter et al. 1999; Black et al. 2002).

COSEWIC (2003) noted that some skippers (notably the Dakota skipper) are not as popular as 10 some other showy butterflies, and this may well be the case for the Mardon skipper. Regardless, collection from any of the sites where the Mardon skipper population is small may increase the vulnerability of the small population (S. Black, pers. comm.., 2005, 2006).

C. Disease or predation.

Disease and predation may be a threat to populations that are suppressed by other factors, but no specific examples are known for the Mardon skipper.

D. The inadequacy of existing regulatory mechanisms.

Although there is no Washington State Endangered Species Act, the Washington Fish and Wildlife Commission has the authority to list species and provide protection from direct take. The Washington Fish and Wildlife Commission designated Mardon skipper as an endangered species in the state of Washington (Washington Administrative Codes 232-12-014, Endangered species; 232-12-011, Threatened species, Appendix D). This designation provides protection from direct take of the species but does not provide any protection to the habitat where the species is found. The Mardon skipper is not listed as a protected species in Oregon or California (Black et al. 2002).

The Mardon skipper was listed as a State endangered species in Washington in November 1999 (WAC 232–12–014). Although there is no State Endangered Species Act in Washington, the Washington Fish and Wildlife Commission has the authority to list species (RCW 77.12.020). State listed species are protected from direct take (primarily collecting), but their habitat is not protected (RCW 77.15.120). Under the Washington State Forest Practices Act the Washington State Forest Practices Board has the authority to designate critical wildlife habitat for State listed species affected by forest practices (WAC 222–16–050, WAC 222–16–080). However, critical wildlife habitat has not been designated by the Washington State Forest Practices Board for the Mardon skipper.

Washington has prepared a draft Comprehensive Wildlife Conservation Strategy (CWCS) (WDFW 2005). The plan is a non-regulatory statewide approach to conservation in Washington and fulfills a requirement to access two new Federal grant programs. The draft CWCS identifies the Mardon skipper as a “species of greatest conservation need” with a high number of threats, a high vulnerability, and a partly adequate amount of current protection. The draft strategy describes the basic biology and distribution, general and specific problems, and general conservation strategies for the Mardon skipper. It also identifies specific conservation actions including protecting known sites and potential habitat, and investigating limiting factors. Development of the Washington CWCS has proceeded on a parallel track with completion of ecoregional assessments for nine ecoregions within Washington. For each ecoregion, WDFW will complete Wildlife Action Plans that will include the species-specific proposed conservation actions. The Wildlife Actions Plans are anticipated to be completed in 2008. However, it is unknown what actions will be proposed or when such actions will be implemented.

The Mardon skipper is ranked as critically imperiled and threatened by extinction by the Oregon 11 Natural Heritage Information Center (2004). The Oregon Natural Heritage Information Center lists the Mardon skipper as imperiled (S2). Oregon has a State Endangered Species Act, but the Mardon skipper is not State listed. Although this species is on the Oregon sensitive species list and is considered critically sensitive, this designation provides little protection (ODFW 1996, OAR 635–100–0040). The “critical” designation indicates a species for which a listing as threatened or endangered is pending or listing as threatened or endangered may be appropriate if immediate conservation actions are not taken. Once an Oregon “native wildlife” species is federally listed as threatened or endangered, it is included as a State listed species and receives some protection and management, primarily on State-owned or managed lands (OAR 635–100– 0100 to OAR 635–100–0180; ORS 496.171 to ORS 496.192). The Oregon Department of Fish and Wildlife (ODFW) prepared a draft Comprehensive Conservation Strategy (ODFW 2006). The plan is a non-regulatory statewide approach to conservation in Oregon and fulfills a requirement to access two new Federal grant programs. The draft strategy identifies the Mardon skipper as a “strategy species.” Strategy species are found in low numbers at few locations and are threatened. They are considered an at-risk species. The plan targets conservation actions for the most at-risk species. The strategy generally identifies special habitat needs, limiting factors and data gaps for the streaked horned lark. It also identifies specific conservation actions needed for the species. The strategy also identifies ecoregion opportunity areas; in the case of the Mardon skipper, Klamath ecoregion. At this time, it is unknown how and when any actions tied to the Conservation Strategy will be implemented.

In California, the Mardon skipper is considered a “special animal” and the California Natural Diversity Database (CNDDB) is interested in tracking the status of the species. The California Natural Diversity Database ranks the Mardon skipper as S1, and has assigned an imperiled designation to the species. California has an Endangered Species Act but the Mardon skipper is not listed as threatened or endangered under the state ESA. The Comprehensive Wildlife Action Plan (2006) placed the Mardon skipper on its Special Animal list, which is also referred to a “species at risk” or “special status species” or “a species of conservation concern” known to occur in the Klamath ecoregion of northwestern California.

In summary, there continue to be ongoing threats to the species due to the inadequacy of existing regulatory mechanisms. Although both Washington and Oregon have completed Comprehensive Conservation Strategies, it remains unclear when and how the strategies will be implemented and result in on-the-ground conservation actions for Mardon skipper.

E. Other natural or manmade factors affecting its continued existence.

Most insect populations experience large fluctuations in numbers, from year to year and within and between locations. Weather, predation, disease and even the timing of surveys may cause annual changes in butterfly numbers of an order of magnitude (for example, from one to 10,10 to 100, or 100 to 1000 etc.). Small populations (those less than 50 individuals) are acutely vulnerable to extirpation from any one of the threats presented above. Locations where Mardon skippers have been extirpated are unlikely to be recolonized because surviving Mardon skipper populations are widely separated, are very small, and Mardon skippers are relatively sedentary and do not have the ability to disperse great distances. Almost all remaining Mardon skipper 12 population numbers are small and it is unlikely that Mardon skipper would recolonize an area unless the distance between sites was less than 1.6 km (Runquist 2004).

SUMMARY OF REASONS FOR ADDITION, REMOVAL OR LISTING PRIORITY CHANGE: Not Applicable.

CONSERVATION MEASURES PLANNED OR IMPLEMENTED

No conservation agreements have been finalized for the Mardon skipper butterfly. A Candidate Conservation Agreement (CCA/CCAA) is currently being developed for several grassland associated species, including the Mardon skipper. Several agencies (DOD (Army and McChord Air Force Base), WDFW, Washington Department of Natural Resources, Thurston County, Port of Olympia and TNC) are collaboratively working with the FWS to develop this agreement. A draft agreement is anticipated during FY 2007.

A small private parcel of prairie land was acquired in FY 2005 with funding from section 6 Recovery lands acquisition funds. This 130 acre parcel will contribute to the conservation of prairie associated species in south Puget Sound. Mardon skipper is a candidate species that will be introduced onto this parcel when the captive rearing methods have been improved and larvae are available to move onto the site. TNC will oversee management of the parcel and coordinate with FWS on activities that are planned for the parcel.

Restoration of grasslands in the south Puget Sound region of Washington has resulted in temporary control of Scot=s broom and other invasive woody plants through the use of herbicides, mowing, grazing, and prescribed fire. The TNC of Washington, with funding from the FWS and DOD, has conducted restoration projects on grassland habitat at Fort Lewis Military Reservation, Thurston County’ Glacial Heritage Preserve, Scatter Creek Wildlife Area, the recently acquired Morgan property, and at the WDNR’s Mima Mounds and Rocky Prairie Natural Area Preserve.

Biologists from the WDFW were funded by FWS to implement and refine captive rearing methods for Mardon skipper, at the Oregon Zoo. This work has been ongoing for approximately three years and the early results have not been successful for Mardon skipper. Because of disease problems in the propagation facility, work on Mardon skipper has been slowed and the focus is to perfect the propagation technique with Taylor’s checkerspot, another candidate butterfly.

FWS funded the U.S. Forest Service (USFS) with an Interagency Agreement in late FY 2003 to implement habitat restoration projects for the Mardon skipper at two locations on the Gifford Pinchot National Forest. This is a continuation of ongoing work being done by the USFS. In 2005, the FWS coordinated with the Gifford Pinchot National Forest to complete restoration on about five acres of Mardon skipper habitat. This work was a continuation of restoration work initiated during 2003 to remove trees that have encroached onto the grassland habitat for the Mardon skipper. Habitat for the Mardon skipper is relatively rare on the Gifford Pinchot National Forest lands where approximately 15 acres have been restored during the past five years.

13 Through an initiative from the Western Washington Fish and Wildlife Office, the FWS has worked with several agencies (Bureau of Land Management in southern Oregon, USFS on Gifford Pinchot, Mount Hood and Willamette National Forests) to train biologist to survey for Mardon skippers on their lands. This training has increased knowledge, awareness and interest throughout the region to monitor grassland habitat for the Mardon skipper and several new populations have been identified in recent years.

In the spring, 2004, the Arcata Field Office (FWS) funded Eric Runquist, a Ph.D. candidate at UCD, to search for new populations of Mardon skipper. Mr. Runquist searched in the vicinity of the original California population near High Divide Ridge, Six Rivers National Forest (R. Hamlin pers. comm. 2004). Locations for Mardon skipper were surveyed in southern Oregon by Forest Service and FWS biologists and by entomologists from the Xerces Society.

Reports submitted to the FWS from Dana Ross in 2005 and 2006 summarized surveys he conducted in southern Oregon for Mardon skipper. A total of 27 locations were surveyed one or more times, including several locations that were surveyed for the first time. Because of the annual variation in flight period for the Mardon skipper, the surveys were conducted at three distinct times within the suspected flight period, from early June through early July 2005. During the early survey period only a handful of butterflies were observed, the largest number of butterflies were documented during the late June period when a total of 245 male and females were observed at 15 of 21 sites surveyed. Seven new Mardon skipper locations were discovered in Klamath and Jackson County, Oregon. Although these new locations were documented to have Mardon skippers, only one of the seven locations had more than 10 individuals (17 at one Forest Service site) and should not be considered as new “populations” because of the close proximity (<1 km) to other known Mardon skipper locations.

In the spring of 2005 an interagency Mardon skipper Work Group was convened by the Interagency Special Status/Sensitive Species Program for Region 6 of the Forest Service and Oregon/Washington Bureau of Land Management. This collaboration between the two Federal land management agencies included technical input from the U.S. Fish and Wildlife Service, the Washington Department of Fish and Wildlife, and the U.S. Forest Service Research Station. The task of this work group was to summarize the current state of the knowledge on the biology and ecology of the Mardon skipper butterfly. A draft Conservation Assessment has been produced (2006). It provides guidance and direction for survey and management activities that will occur for the species on Forest Service/BLM lands in Oregon and Washington.

The interagency Mardon skipper work group plans to continue surveys in 2007. These will be expanded to include the Willamette and Mount Hood National Forests, including appropriate grassland habitat in the Columbia Gorge National Scenic Area. The Wenatchee National Forest will expand their survey efforts in the vicinity of the recently detected population found near Pinegrass Ridge on the Naches Ranger District. The Medford BLM district has contracted with Xerces Society for 2007 surveys in the area of Mt Ashland in southern Oregon. Based on a recent specimen (labeled 1979) that was collected in the Gold Beach area of coastal Oregon, Dana Ross will be contracted by the Coos Bay BLM district to survey for Mardon skippers in spring 2007.

14 A Draft Survey protocol has been produced by the interagency Mardon skipper Work Group. An early version of the protocol has been distributed for review in February 2007. These survey methods have been used, improved and modified over the past decade (A. Potter pers. comm., 2007), but only recently (2007) were the procedures summarized in a written document.

On Fort Lewis, weed control programs to reduce the cover of Scot’s broom and nonnative, invasive grasses have been ongoing for the past decade and will continue with caution so that unintended consequences of the actions do not harm local butterfly populations. Fort Lewis’s Land Rehabilitation and Management staff have been collecting seed and growing nectar plants to reestablish onto prairies where Mardon skipper and other prairie butterflies are found.

The WDFW continues to tackle the nonnative grass problems at their local Wildlife Area in Thurston County. This 639 acre parcel is mowed once per year and spot removal treatments to remove Scot’s broom are implemented annually.

SUMMARY OF THREATS

The Mardon skipper spends its entire life cycle in one location, and its dispersal ability is probably limited. Threats include continued habitat loss, fragmentation and degradation due to development, overgrazing, use of herbicides and pesticides, encroachment of nonnative and native vegetation, succession from native grassland to forest, fire suppression; direct loss of individuals due to fire; recreational activities; insect collecting; and random, naturally occurring events. A restricted dispersal ability limits the likelihood of recolonization once a population is lost. The magnitude of threats is high because of the small population sizes and disjunct distributions that limit dispersal between populations. Loss of any of the populations could threaten the continued existence of the species. Threats are non-imminent because the number of documented locations for the species has increased from less than 10 in 1998 to greater than 70 rangewide in 2007. However, very few populations (< 15% rangewide) have more than 50 individuals; most of the recently reported populations have estimates of less than 10 individual Mardon skippers. We find that this species is warranted for listing throughout all its range, and, therefore, find that it is unnecessary to analyze whether it is threatened or endangered in a significant portion of its range.

We have assigned a listing priority number of 5 to the Mardon skipper.

RECOMMENDED CONSERVATION MEASURES

All current and high priority historic locations for Mardon skipper butterflies should be monitored. Potential suitable habitat composed of native species of bunchgrasses and forbs should be surveyed for the presence of the Mardon skipper. If the species was found to occupy a site, a formal survey or a complete assessment of the site should be made. Management actions that improve the amount and distribution of suitable habitat for Mardon skipper butterflies are recommended. Recommended management procedures for improving habitat include mowing (usually early fall or pre-emergence of larvae in the spring), prescribed burning of patches but never more than about a quarter of the site to conserve eggs and larvae, and judicious use of herbicides. The acquisition of grassland and bald habitat should be a high priority to conserve 15 Mardon skipper, using Federal funds (Section 6 Recovery land funding).

LISTING PRIORITY

THREAT

Magnitude Immediacy Taxonomy Priority High Imminent Monotypic genus 1 Species 2 Subspecies/population 3 Non-imminent Monotypic genus 4 Species 5* Subspecies/population 6 Moderate Imminent Monotypic genus 7 to Low Species 8 Subspecies/population 9 Non-imminent Monotypic genus 10 Species 11 Subspecies/population 12

Rationale for listing priority number:

Magnitude: The magnitude of the threat is high because of the small size of all populations and their disjunct distribution. The great distances between the known locations for the species would not allow for dispersal of the species between populations. Loss of any population could lead to extirpation of the species at any of these locations.

Imminence: Mardon skippers face a variety of threats that may occur at any time at any of the locations. Threats to Mardon skippers are non-imminent because the number of known locations for the species has increased from less than 10 in 1998 to greater than 70 populations rangewide in 2007. Very few individuals have been found at most of the known locations, less than 10 locations (< 15% rangewide) are known to harbor greater than 50 individuals and the specific location could easily be lost by changes in vegetation composition or from the threat of wildfire. In the Puget Sound region the number of populations has contracted to two and the threats are imminent. The disjunct distribution of the species over the species range has increased within the four disjunct regions found in Washington, Oregon and California, including additional new population found in northern California, eastern Washington and southern Oregon, therefore broadening its spatial distribution. 16 YES Have you promptly reviewed all of the information received regarding the species for the purpose of determining whether emergency listing is needed?

Is Emergency Listing Warranted? NO. At this time, emergency listing of the Mardon skipper is not warranted. The number of documented populations of Mardon skippers has expanded from less than 10 in 1998 to greater than 70 in 2007. New populations have been found in northern California about 10 miles from the currently known population at High Divide Ridge, in eastern Washington on the Wenatchee National Forest and in southern Oregon, primarily on BLM and Forest Service lands. Xerces Society, WDFW and FWS recently provided training to the Willamette NF biologists in early June 2004, in addition to the training that was provided to biologists on the Mt. Hood, Gifford Pinchot and Six Rivers National Forest in 2003. New finds may continue because there are more trained people looking for Mardon skippers. The discovery of new populations and the wide geographic range for the Mardon skipper provides a buffer against threats destroying all existing habitat simultaneously or jeopardizing the continued existence of the species.The need for an emergency listing of this species is not recommended at this time.

DESCRIPTION OF MONITORING:

The Mardon skipper has received considerable attention since it was first put onto the candidate list in October, 1999. Based on early work by Dr. Robert Michael Pyle (1989) the Mardon skipper was brought to the attention of WDFW and FWS biologists who have monitored the species on south Puget Sound grasslands since 1996. WDFW biologists in cooperation with Dr. Pyle began searching historic locations for the species in the southern Cascades of Washington in the same year. Since 1996, annual searches in Washington have been conducted by WDFW biologist at south Puget Sound and southern Cascades regions. The loss of the grassland ecosystem was already a concern for the FWS and the Forest Service Pacific Northwest Forest and Range Experiment Station (Olympia), who had begun work on south Puget Sound grasslands in the early 1990s. The early work focused on the rapid changes to the grassland ecosystem from forest encroachment and invasion by nonnative vegetation. Rare and threatened plants such as Castilleja levisecta, (Federally listed as Threatened, 1997) and other former candidate plants like Aster curtus) were a conservation concern of the FWS and Washington DNR. By the early 1990’s, status reviews and research began on several plant, mammal, bird and lepidopteran species that were known to depend upon this ecosystem in the south Puget Sound region.

Biologists from the USFS (Gifford Pinchot National Forest, (GPNF)) and the FWS Northwest Forest Plan have monitored the species on the GPNF every the summer from 2000 - 2005, where new populations have been found. In the summers of 2002 through 2005, searches were made on the Bureau of Land Management’s property in Jackson and Klamath Counties, Oregon where Mardon skippers are known from four locations. FWS biologists from Arcata, California have been working with National Park Service biologist and lepidopterists, Dr. Sterling Matoon and John Emmel to search for and monitor the species in northern California for the last two years. Matoon searched the High Divide Ridge in Del Norte County, California since 1979, when he first discovered the species at this location. Searches in 2004 identified a second population in northern California near the Bald Hills region of Redwood National Park, Del Norte County, 17 California, about 10 miles south-southeast of the original population located on High Divide Ridge. Ten miles is considered too distant for Mardon skipper dispersal between the two locations (Runquist 2004) Fewer than 50 butterflies were observed at this location when it was originally discovered (R. Hamlin pers. comm. 2004). Surveys at this location in 2007 detected fewer than 5 individual butterflies (K. Schmidt 2007). Extensive surveys were completed in southern Oregon during 2005 and 2006 by Dana Ross, (Ross 2006, 2007). Surveys in the vicinity of Gold Beach, in southwestern coastal Oregon are planned for 2007. Survey crews from TNC and Fort Lewis Fish and Wildlife Staff will continue annual butterfly surveys that are funded by DOD and carried out on DOD lands.

COORDINATION WITH STATES

We, the Western Washington Fish and Wildlife Office have coordinated with the Washington Department of Fish and Wildlife on Mardon skipper surveys since 1997 and have periodically funded restoration projects to benefit Mardon skipper at Scatter Creek Wildlife Area, a local prairie site managed by WDFW. In 2001, we funded the WDFW and WDNR with a cooperative agreement to partner with us on surveys for Mardon skipper. WDFW has been instrumental in their coordination with the FWS on Mardon skipper and have taken the lead on field workshops to train agency and private consultants on survey methods and the identification of Mardon skipper throughout the species range. We continue to work with WDFW and WDNR on efforts to conserve butterflies and plan to complete a CCA/CCAA during FY 2007 that will provide long-term conservation to more than 26, 000 acres of grassland habitat in the south Puget Sound region of western Washington.

For this review, we gathered information from all three states where the species is known to occur.

18 LITERATURE CITED

Agee, J.K. 1993. Fire Ecology of Pacific Northwest Forest. Island Press, Washington, DC. 493 pp.

Beyer, L. and S. Hoffman Black. 2007 Site Utilization by Adults and Larvae of Mardon skipper Butterfly (Polites mardon) at four sites in Washington and Oregon. Final Report to the Forest Service and BLM. 72 pp.

Black, S.H., K. Hitt, and M. Vaughan. 2002. Petition to list the Mardon skipper butterfly (Polites mardon) as an endangered species under the U.S. Endangered Species Act. Report submitted to The Xerces Society, Gifford Pinchot Task Force, The Nortwest Environmental Defense Center, Center for Biological Diversity, Oregon Natural Resources Council, Friends of the San Juans, and Northwest Ecosystem Alliance. 25 pp.

Crawford, R.C. and H. Hall. 1997. Changes in the south Puget prairie landscape. Pages 11B16 in P. V. Dunn, and K. Ewing, eds. 1997. Ecology and Conservation of the South Puget Sound Prairie Landscape. The Nature Conservancy, Seattle, WA. 289pp.

Dana, R.P. 1991. Conservation management of the prairie skippers Hesperia dacotae and Hesperia ottoe: basic biology and threat of mortality during prescribed burns. U. of Minnesota. Minnesota Agricultural Experiment Station Bulletin 594B1991(ADBSBB 5511BS). 62 pp.

Edwards, W.H. 1881. Description of new species of butterflies. Papilio 1(4):43B48.

Ehrhardt, A. 1995. Diurnal Lepidoptera: sensitive indicators of cultivated and abandoned grassland. Journal of Applied Ecology 22:849B861.

Harke, V. 2001. U.S. Fish and Wildlife Service surveys for Mardon skipper in southwestern Washington summary year 2001. Unpublished report submitted to Washington Department of Fish and Wildlife, Olympia, WA. 19 pp.

Hays, D.W., A. Potter, C. Thompson, and P. Dunn. 2000. Critical habitat components for four rare south Puget Sound butterflies. Washington Department of Fish and Wildlife, Olympia, and The Nature Conservancy of Washington, Seattle. 35 pp.

Kruckeberg, A. R. 1991. The Natural History of Puget Sound Country. University of Washington Press, Seattle, WA. 468 pp.

Morgenweck, M. and P. Dunn. 2003. Fort Lewis Butterfly Survey. The Nature Conservancy – Washington. Unpublished data.

Newcomer, E.J. 1966. Life histories of three western species of Polites. J. Res. Lepid. 5:243B247. 19 Parker, I., W. Harpole, and D. Dionne. 1997. Plant community diversity and invasion of the exotic shrub Cytisus scoparius: testing hypotheses of invasibility and impact. Pages 149- 161 in P. V. Dunn, and K. Ewing, eds.. 1997. Ecology and Conservation of the South Puget Sound Prairie Landscape. The Nature Conservancy, Seattle, WA. 289pp.

Potter, A.E., and D. W. Hays. 1998. Fieldwork conducted by Washington Department of Fish and Wildlife for the critical habitat components of candidate south Puget Sound prairie butterflies - Interim 1998 Field Season. Washington Department of Fish and Wildlife. Olympia, WA.

Potter, A. and J. Fleckenstein. 2002. Mardon skipper range and distribution in Washington in relation to state and federal highways with a habitat description and survey method guidelines. Final report to Washington Department of Transportation. Washington Department of Fish and Wildlife, Olympia, WA. 18 pp.

Potter, A., J. Fleckenstein, S. Richardson, and D. Hayes. 1999. Washington state status report for the Mardon skipper. Washington Department of Fish and Wildlife, Olympia, WA. 39 pp.

Pyle, R.M. 1989. Washington butterfly conservation status report and plan. Washington Department of Wildlife, Nongame Program, Olympia, WA. 217 pp.

Pyle, R.M. 2002. The Butterflies of Cascadia. Audubon Society. Seattle, Washington. 420 pp.

Ross, Dana. 2005. 2005 Surveys for Mardon skipper (Polites mardon klamathensis) on Public Lands in Southern Oregon. A report submitted to the U.S. Fish and Wildlife Service, Portland, Oregon. 10 pp.

Ross, Dana. 2007. 2006 Surveys for Mardon skipper (Polites mardon klamathensis) on Public Lands in Southern Oregon. A report submitted to the U.S. Fish and Wildlife Service, Portland, Oregon. 15 pp.

Runquist, E. 2004. 2004 Line Transect sampling and surveys for Mardon skippers (Polites mardon) in Del Norte County, California. Report submitted to USFWS, Arcata, CA.

Runquist, E. 2004. Workshop on the Ecology and Status of the Mardon skipper (Polites mardon): An unusual Pacific Nortwest butterfly. Ashland, OR.

Sietz, R., A. Potter, K. Van Norman, N. Barrett, and M. Wainwright. 2007. Survey Protocol for Mardon skipper (Polites mardon). Submitted to USDA Forest Service, Region 6 and USDI BLM, Oregon and Washington. 29 pp.

20 Do not concur: Director, Fish and Wildlife Service Date

Director's Remarks:

Date of annual review: March 29, 2007

Conducted by: T. Thomas

Reviewed by: Jodi Bush Date: March 30, 2007 Division Manager, Listing and Recovery, WWFWO

Ken Berg Date: March 30, 2007 Manager, WWFWO

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