BLM LIBRARY 8807 0 MM teervation Assessment and Conservation Strate^ for tlie Townsend’s Big-Eared Bat An interagency conservation program (Idaho State Conservation Effort) was initiated in Idaho in late 1993 to remove threats and develop Conservation Agreements for species at risk of being listed as threatened or endangered. An emphasis on early conservation efforts for species at risk allows opportunities for State and Federal agencies and other interested parties to stabilize and recover these species and their ecosystems before listing becomes a high priority. Addressing the conservation needs of at risk species maintains management flexibility, reduces potential conflict and restrictive land use policies, avoids the confrontational atmosphere often associated with listing, and provides an ecologically sound and cost-effective means to conserve species. The primary agencies involved are the U.S. Fish and Wildlife Service, Bureau of Land Management, Regions 1 and 4 of the U.S. Forest Service, Idaho Department of Fish and Game, and Idaho Department of Parks and Recreation. The Habitat Conservation Assessment summarizes historic and current distribution and abundance of the Townsend’s big-eared bat throughout its’ range and identifies threats to the species’ existence. The Conservation Strategy prescribes conservation actions to remove threats to the species. All comments received will be considered in preparation of a final Conservation Strategy. The Idaho State Conservation Effort is seeking comments on this draft document and any additional information that would contribute to the conservation of the species. Submit written comments on the Draft by September 30, 1995 to: Charles E. Harris, Idaho Department of Fish and Game, P.O. .Box 25, Boise,. ID 83707. ‘ This report should be cited as: Idaho State Conservation Effort. 1995. Habitat conservation assessment and conservation strategy for the 'fownsend’s big-eared bat. Draft unpubl. rep. no. 1. Boise, Id. Spotted bat and trumpeter swan illustrations >cQUjttesy of Erica Craig. ^3'f , C5-^ H TABLE OF CONTENTS - <5 - Introduction 2 C ^ Involved Parties 2 Species Involved 2 Taxonomy/Systematics 2 Description... 3 Life History 4 Habitat Associations 4 Roosting Ecology 4 Foraging Behavior and Habitat 9 Diet 10 Reproduction and Development 10 Geographic Distribution and Status 11 Arizona 12 British Colombia 15 California 15 Colorado 16 Idaho 17 Kansas 20 Montana 21 Nebraska 22 Nevada 22 New Mexico 23 North Dakota 24 Oklahoma 24 Oregon 25 South Dakota 26 Texas 26 Utah 26 Washington 28 Wyoming 29 Threats 29 Anthropogenic Threats 30 Natural Threats 36 Preparers 37 Literature Cited 38 Conservation Strategy 46 Appendix A (Evaluation of Bat Use in Abandoned Mines) 53 Appendix B (Designs for Bat Gates) 63 Appendix C (Guidelines for the Protection of Bat Roosts) 73 D©nver Fedsral CGnt©r Bldg. 50, OC-521 RO. Box 25047 Denv©r, CO 80225 ■■ v??j •V ' ■ ' •■; ' ,:v ;:t«-Ufeaa: 'Sr-':- JjSi^ ns ■. r ...» i> . '. .»'■«. « s it , u- >V. * • ’ W- ■/ / ■'•' ‘A ■ »,.A^’>k,,:,' . . ..m • . 'L “• /‘'.•y-T I ' * f. s »’■> ■• f *'"'a •*'#,,' ^ ' '■ '.■• * ■■ : , " * V- .»•. ■■ ^ . •■ .•-. ■ ^ ", , ,1 ‘.1 ■ < s •> 0 . ,: » t AV . . , , A .;,VI i - , < < <™ ■. '•< v^ - :'?v ■ t ^ •'* i , » lajS V* -' " ' t.;-' ■'■A‘ firs /U' . V ' ■ * ■ ' • ' ‘ > • . . a.;V?5: , t > A. y^. .; ;■ .'■; . ’■ :[-^;rp^^. f-rji •-* -«)S£» c ‘f :k V -'■:. y ^ ' : AjTifVfe ’■ '-; A= 9 ,T Vij i. '■'•■. “j-t'vs ' .' . ‘ . . . , . .... ■'T» ■■ n K-f't: If. i ^ C,* .I. y i(^.> .ij*j I r « • t. ^ c V * 4 ' '-'•-Vvlvl A . wmM ' • - ^ Sn. ... ‘ / >?•; VJBidU.MJa •ST» ibO fsisfjs^ JovnsQ fsa-oo ,0?, ,gb!8 ' t-> >^' BSSO ^oa DO ,.vneG :^ 1300 caves and mines have identified several factors important to C. townsendii in selection of maternity sites, including roost temperature, roost dimensions, light quality, and air flow. Roost temperature appears to be critical (Pearson et al. 1952, Lacki et 1994, Pierson and Rainey 1994). Colonies generally form tight clusters to help maintain high body temperatures and promote the sharing of body heat during pregnancy and lactation (Humphrey and Kunz 1976). Recorded temperatures in maternity roosts throughout California vary between 19°C in the cooler regions to 30 C in the warmer southern regions (Pierson et al. 1991). Colonies also sometimes change roost sites (either different areas of the same roost, or different roosts) during the maternity season, seeking cooler places during early pregnancy and warmer sites in later pregnancy and once the young are bom (Tipton 1984, Pierson et al. 1991). C. townsendii also requires a relatively spacious roost. The majority of the roosts examined in California (Pierson et al. 1991) are at least 30 m in length, with the roosting area located at least 2 m above the ground. Maternity clusters are often located in ceiling pockets or along the walls just inside the roost entrance, within the twilight zone. Bat species which have been observed roosting in the same caves/structures with C. townsendii maternity colonies include Macrotus califomicus, Myotis ciliolabnm, Myotis lucifugus, Myotis thysanodes, Myotis velifer, Tadarida brasiliensis (B. Luce pers. comm., Cahalante 1939, Stager 1939, Pearson et al. 1952, Twente 1955, Peterson and Perkins 5 1994). Hibemacula Hibernating C. townsendii individuals have been found mainly in caves and mines (Pearson et al. 1952, Barbour and Davis 1969, Humphrey and Kunz 1976, Center 1986, Wackenhut 1990, Bosworth 1994, Doering 1995, Perkins et al. 1995) and occasionally in buildings (Dalquest 1947). Recent work by S. Altenbach (pers. comm.) in New Mexico has demonstrated the importance of deep mine shafts as hibernating sites for this and other bat species. Populations are known in lava-tube caves in Idaho (Center 1986, Wackenhut 1990, Doering 1995). Winter roosting behavior for hibernating C. townsendii varies throughout its distribution. Suitable caves in the eastern U.S. seem to be limited, and hibernating aggregations number as high as 1,000 to 6,000 (Rippy and Harvey 1965, Stihler and Hall 1993). Large aggregations have also been found in colder areas of the western U.S., e.g., 460 in a cave in northern California (Pierson and Rainey 1994), 1,000 in a cave in South Dakota (M. Bogan pers. comm.), >300 at two sites in Oregon (Perkins 1990), 400 in a lave-tube cave in southern Idaho (Wackenhut 1990) and several thousand in a mine shaft in New Mexico (S. Altenbach pers. comm.). More typically, however, especially in the West, C. townsendii tends to form relatively small hibernating aggregations of a few to several dozen individuals (Barbour and Davis 1969, Humphrey and Kunz 1976, Kunz and Martin 1982, Wackenhut 1990, Pierson et al. 1991). In California the larger aggregations are confined to areas which experience prolonged periods of freezing temperatures (Pierson and Rainey 1994). Studies in the western U.S. have shown that C. townsendii selects roosts with stable, cold temperatures, and moderate airflow (Humphrey and Kunz 1976, Kunz and Martin 1982). Individuals roost on walls or ceilings, often near entrances (Humphrey and Kunz 1976, Twente 1955). If undisturbed, individuals will frequently roost < 3 m off the ground (Perkins et al. 1994), and have been found in air pockets under boulders on cave floors (E.D. Pierson pers. comm.). Temperature appears to be a limiting factor in roost selection (Center 1986). Recorded temperatures in C. townsendii hibemacula range from -2.0°C to 13.0°C (Pearson et al. 1952, Twente 1955, Humphrey and Kunz 1976, Center 1986, Pierson et al. 1991), with temperatures below 10®C being preferred (Perkins et al. 1994, Pierson and Rainey 1994). Individuals appear to be sensitive to changes in temperature and humidity. In the warmer regions of California, individuals arouse more often from a state of hibernation and are thought to feed on warm nights, sometimes appearing in night roosts in buildings (Pearson et al. 1952, Pierson et al. 1991). In general, C. townsendii individuals begin to arrive at hibemacula in October and reach maximum numbers in January. In early winter, individuals may hibernate near entrances, relying on the cool substrate to maintain stable body temperatures. If temperatures at entrances drop below freezing, bats may arouse and move into the deeper, more stable parts of caves and mines (Kunz and Martin 1982). In Oklahoma and Kansas, females 6 outnumbered males until January, at which time the sex ratio became 1:1. Males chose warmer sites than females; weight loss during the hibernation period was roughly 55% for females and 57% for males (Humphrey and Kunz 1976). Bat species known to occur within C. townsendii hibemacula include Antrozous pallidus, Eptesicus fuscus, Myotis califomicus, Myotis ciliolabrum, Myotis evotis, Myotis sodalis, Myotis thysanodeSj Myotis velifer, Myotis volans, Pipistrellus subflavus, and Corynorhinus rafinesguii (Dalquest 1947, Pearson et al. 1952, Twente 1955, Handley 1959, Rippy and Harvey 1965, Kunz and Martin 1982, Marcot 1984, Center 1986, Perkins and Levesque 1987) Summer Roosts of Males and Non-Reproductive Females Summer roosts, which are not maternity roosts, are typically comprised of males and non- reproductive females (Pearson et al. 1952, Barbour and Davis 1969, Humphrey and Kunz 1976). Most commonly these roosts contain one to several individuals, although a summer colony of > 1,000 males has been reported in Kentucky (Lacki et al. 1994). These roosts include caves (Dalquest 1947, Pearson et al. 1952, Humphrey and Kunz 1976), buildings (Dalquest 1947, Findley and Negus 1953, Barbour and Davis 1969, Senger et al. 1972), shallow prospect holes (Hardy 1941), bridges (Pierson and Rainey 1993), the passages between fallen boulders on a cave floor (Commissaris 1961), and abandoned mines (Whitlow and Hall 1933, Pearson et al. 1952, Humphrey and Kunz 1976). G. Fellers (unpubl. obs.) radiotracked two reproductive females to the cavities of a coast redwood and a California bay tree where they remained for two days before returning to their maternity colony. This is the first such observation of C. townsendii roosting in trees and it raises the possibility that this typically cavern-dwelling species may make use of large hollows in mature trees and snags. Bat species that are associated with C. townsendii in non-maternity summer roosts include Antrozous pallidus, Idionycteris phyllotis, Myotis califomicus, Myotis evotis, Myotis lucifugus, Myotis thysanodes, Myotis volans, Myotis yumanensis, Macrotus califomicus, and Tadarida brasiliensis (Dalquest 1947, Pearson et al. 1952, Commissaris 1961, Dyck and Perkins 1984) Night Roosts C. townsendii do not form large night roosting aggregations as do some other species (e.g., some Myotis species), but rather appear in small numbers in a variety of sites, including caves (Dalquest 1947, Graham 1966), open buildings (Dalquest 1947, Rainey and Pierson 1993), rock shelters (Lacki et al. 1993), bridges (Perkins and Levesque 1987, Perimeter 1993), cement culverts beneath roads (Hall 1994) and mines (Keller 1994). Lacki et al. (1993) used categorical data analyses to determine that C. t. virginianus selects night roosts 7 that have large entrances and deep passages. Bat species known to occur with C. townsendii in its night roosts include Antrozous pallidus, Eptesicus Juscus, Myotis califomicus, Myotis ciliolabrum, Myotis evotis, Myotis lucijugus, Myotis thysanodes, Myotis volans, and Myotis ywnanensis, (Dalquest 1947, Pearson et al. 1952, Easterla 1966, Perimeter 1993). Transient Roosts C. townsendii has occasionally been found aggregated in roosts (e.g., caves and mines) very early in the spring and in the fall at sites close to, but not the same as, those used as maternity roosts (E. D. Pierson unpubl. data, Dalton and Dalton 1994). Perkins (1995) presents evidence that some spring aggregations are pregnant females using specific sites as "staging” roosts for colony formation prior to parturition. FORAGING BEHAVIOR AND HABITAT C. townsendii is a late flyer, emerging from the roost primarily after dark (Barbour and Davis 1969, Jones 1965, Bell 1980, Tipton 1983), an average of 45.5 minutes after sunset (Clark et al. 1993). A netting study by Cockrum and Cross (1964) suggested two peaks of activity during the night. A radiotracking study by Clark et al. (1993) showed that during lactation females returned to the nursery roost up to three times per night, but after lactation remained away from the roost all night. Remote monitoring of activity at a nursery roost entrance in California offered similar data, with a bimodal concentration of activity prior to parturition, and nearly continuous activity through the night after the young were bom (Pierson et al. 1991). Recent radiotracking and light-tagging studies have found C. townsendii foraging in a variety of habitats. In Oklahoma, C. t. ingens preferred edge habitats (along intermittent streams) and open areas (pastures, crops, native grass) near wooded habitat (Clark et al 1993). Light- tagging studies in West Virginia (V. Dalton pers. comm.) showed a bimodal foraging pattern for C.t. virginianus, with animals foraging over hayfields during the first part of the night, and within the forest later in the night, travelling up to 13 km from the day roost. Brown et al. (1994) showed that C. townsendii on Santa Cruz Island in California avoided the lush introduced vegetation near their day roost, and travelled up to 5 km to feed in native oak and ironwood forest. Radiotracking studies in northern California have found C. townsendii foraging within forested habitat (Rainey and Pierson 1993), and along heavily vegetated stream corridors, avoiding open, grazed pasture land (G. Fellers unpubl. obs.). C. townsendii is a slow-flying (2.9 to 5.5 m/s), highly maneuverable bat (Hayward and Davis 1964, Findley et al. 1972), which has been observed gleaning insects from vegetation (Howell 1920), and foraging within tree canopies (E.D. Pierson pers. comm.). The extent to which it forages by gleaning is not known. Griffin (1958) determined this species has the ability to echolocate through the nose, allowing it to feed in flight while maintaining full use 8 of its auditory capabilities. It is adept at detecting and avoiding obstacles (Griffin 1958, Griffin et al. 1963), including mist nets (Ross 1967, Barbour and Davis 1969). DIET C. townsendii is a lepidopteran specialist, with a diet consisting of >90% moths (Ross 1967, Whitaker et al. 1977, 1981, Dalton et al. 1986, Sample and Whitmore 1993). Ross (1967) examined the stomachs of 40 C. townsendii, 38 of which contained only lepidopterans, averaging 6-12 mm in length. Dalton et al. (1986) examined 1,222 C. t. virginianus fecal pellets and found the percent volume of the diet to be 97. 1 % Lepidoptera. Shoemaker and Lacki (1993) determined that C. t. virginianus differentially selected noctuid moths. Noctuidae represented only 12.2% of the available moth prey items, but 62.6% of the moths consumed. Moths in the families Geometridae, Notodontidae emd Sphingidae also made up a significant portion of the diet. Representatives of the family Arctiidae made up 37.5% of the available moth prey items, but were not consumed. Sample and Whitmore (1993) identified moth species from wing fragments collected at maternity caves. Of the 28 moth taxa identified, 15 were noctuids. Twenty-one species were forest associated, and 6 associated with open, field habitats. In addition to lepidopterans, small quantities of other insects have been detected in studies of C. townsendiVs diet, particularly Coleoptera and Diptera (Ross 1967, Dalton et al. 1986, Sample and Whitmore 1993). Hemiptera, Hymenoptera, Homoptera, Neuroptera, Trichoptera, and Plecoptera have also been found sporadically (Whitaker et al. 1977, Dalton et al. 1986). REPRODUCTION AND DEVELOPMENT Pearson et al. (1952) studied the reproduction of this species in California, providing most of what we know of the reproductive patterns in this species. Mating takes place in the hibemaculum from October to February, although some females may be inseminated prior to their arrival at the hibemaculum. Copulation is preceded by ritualized courtship behavior. The male emits twittering sounds while approaching the female, then rubs his snout over the face, neck, forearms, and ventral part of the female’s body. Males have been known to copulate with hibernating females, who may breed as early as four months of age. The sex organs of males do not mature until the second year of life, consequently males are not reproductively active their first year. No vaginal plug forms in the female, so it follows that each female may be mated with different males several times during the winter months. The female stores sperm in the uterine lining until spring when ovulation and fertilization occur. Gestation length varies with climatic conditions, but generally lasts from 56 to 100 days. Maternity colonies generally begin to form in March or April, although the timing varies with latitude. For example, colonies begin to form in March in central coastal California, and not until June in interior northern California (G. Fellers pers. comm., E.D. Pierson pers. comm.). A single young is bom sometime between May and July (Easterla 1973b, 9 Pearson et al. 1952, Twente 1955). Natality has been documented at 90-100% (Kunz and Martin 1982). C. townsendii pups average 2.4 g at birth, nearly 25% of the mother’s postpartum mass. Young bats are capable of flight at 2.5 to 3 weeks of age and are fully weaned at 6 weeks (Pearson et al. 1952). Nursery colonies start to disperse in August about the time the young are weaned, and break up altogether in September and October (Pearson et al 1952, Tipton 1983). Adult females that have lost their young depart earlier than lactating females. Young males tend to leave earlier than young females (Barbour and Davis 1969). Pearson et al. (1952) estimated year to year survivorship at about 50% for young, and about 80% for adults. Band recoveries have yielded longevity records of 16 years, 5 months (Paradiso and Greenhall 1967) and 21 years, 2 months (Perkins 1995). GEOGRAPHIC DISTRIBUTION AND STATUS C. townsendii occurs throughout much of western North America, from British Columbia to Mexico, and eastward to Texas, with isolated populations in Kansas, Arkansas, Missouri, Oklahoma, Kentucky, West Virginia and Virginia. The two eastern subspecies, which are not specifically considered in this document, are listed as endangered under the Federal Endangered Species Act. C. t. ingens is confined to a small area at the junction of Oklahoma, Arkansas and Kansas; C. t. virginianus is known from Virginia, West Virginia and Kentucky. Management plans have been prepared for both these subspecies (Hensley and Scott 1993, Tolin 1994). The two western subspecies, C. t. townsendii and C. t. pallescetis, which are the focus of this document, are both currently recognized as Category 2 Federal Candidates. C. L townsendii occurs in Washington, Oregon, California, Nevada, Idaho, and possibly southwestern Montana and northwestern Utah; C. t. pallescens occurs in all the same states as C. t. townsendii, plus Arizona, Colorado, New Mexico, Texas, and Wyoming (Handley 1959). Throughout much of their range in California, Idaho, Nevada, Oregon and Washington there are extensive zones of intergradation for the two subspecies. There has been considerable confusion eunong resource management agency personnel throughout the West regarding where the subspecies currently occur. This issue is confounded by the problem that throughout the zone of intergradation it is frequently impossible to assign individuals to one subspecies or the other. Although, Handley (1959) makes the distinction between the two subspecies based on size and color characteristics, he also claims that one can observe a full spectrum of characteristics for both subspecies within a single population. The results of preliminary DNA studies, using PCR techniques, have also failed to distinguish between the subspecies (W.E. Rainey pers. comm.). For the purposes of this document, we make no distinction between these subspecies. 10 The known distribution of the two western subspecies, C. t. pallescens and C. t. townsendii, is illustrated in Figure 1 . ARIZONA According to Handley (1959), all populations in Arizona would be C. t. pallescens. Arizona Game and Fish (S. Castner pers. comm.), in cooperation with Dr. Virginia Dalton (pers. comm.), have been investigating the status of this species in Arizona. They have identified and are following 13 verified maternity roosts, representing 10 separate colonies. The numbers in the roosts vary from 40 to 350, but yield an estimate of 1,000 adult females. Seven of these sites are old mines. Two historically known populations, both in caves, are now gone — one cave was modified for public use, and the other was mined away. Another population in Agua Caliente Cave, which had 100 adult females two years ago, has dropped by 50% since the State of Arizona, which owns the cave, let a permit to a for-profit company to conduct tours. This colony was likely larger than 100 adults in the past. Another population in Chiricahua Crystal Cave, in the Coronado National Forest, historically had several hundred adult females. The population is currently < 100, but appears to have stabilized since the installation of a gate and restriction of public access. Another maternity colony on Forest Service land is at risk because the only protection provided (a posted sign) is inadequate, and the cave still experiences heavy recreational traffic. An old mine in the Kingman area, which housed the largest known maternity colony, has been destroyed by renewed mining. Although the mine roost was closed during the fall, after the maternity colony had disbanded for the season, no mitigation measures were taken (S. Castner pers. comm.). Two additional maternity sites (about 150 bats in each) have recently been located in old mines along the Bill Williams River (P. Brown pers. comm.). One, on Bureau of Land Management (BLM) land, experiences disturbance by mineral collectors. The other colony is two levels down a shaft on wilderness land, and appears relatively safe from disturbance. J. Bain (pers. comm.) has information on two other potential nursery sites, one in a limestone fissure northeast of Flagstaff (which may have several hundred animals in the summer), and a colony of unknown size near Scottsdale. Recent information is available on two additional maternity sites, both in Grand Canyon National Park (Bain and Bodenhauser 1986, Bain 1988). Stanton’s Cave once housed a large maternity colony of C. townsendii, estimated at several hundred in early September 1976 (Bain and Bodenhauser 1986). A gate built to protect archeological and paleontological resources was reinforced in the mid-1970’s, apparently causing a significant decline in the populations. Surveys in July 1986 suggested that this site was no longer being used as a maternity site. A small maternity colony of 20-30 individuals was located in the Last Chance Mine in August 1987, at the same site where bats had been reported over a number of years by Park personnel. The current status of these two colonies is unknown. 11 Figure 1 . Known distribution of Corynorhinus townsendii pallescens and Corynorhinus townsendii townsendii for the Western United States. A star represents known sites with maternity colonies; triangles, sites where museum specimens have been taken historically; squares, more recent net release site, known hibernation sites, and sites of research. Data represent distributional information available by June 9, 1995. 12 Update 06/09/95 ^9 •<^VIJ, Snwnwij:^; t«w i S«»ht^ •'& I««f «!>«,>tiifU ikriowti 'tMiMit' • tpi ■B3 > a uiillii iVili ' ■ IT-- t 'v;i5^IV ri: i. tia m hi 'W '.'J 4 '4 m ' V'. !:« bit . : >‘*‘i ■ iU-' u| ... ■.■*‘' 7 , •*.” - '-; 1'. A 'V': w ‘■/'?'»V'iiA^ • e'o "IW ..«k" •>7*»4 « « id I *“3 .fl/ V to Tf.' ■ Wl ' '■^Mi . ■' 1^1 ■■■vjtr^v,^ ■/ s.»5a. ' ..a^ ■' $ « :-_rik ; ■3L-«-^i-' M m n\ # mii: r ^4; W m- ‘w -.!« I f. ■v®j •)j,:’riii rAH.)^^'t|-‘ m./' •;'i' ‘ '■*(' ■ (i*si a ::s* ■sr’:‘'V': :4i«.v r. ; i ' ■<}. % ■htii 'M. M One potentially large hibernating site has been identified by J. Bain (pers. comm.) in an excavated cave in the Coconino National Forest. Most known hibernating sites, reported by him and others, contain fewer than 20 animals. He knows of > 60 hibernating sites, all below 6,000 feet, with up to a dozen animals each. Winter surveys of > 1,000 mines, currently being conducted by Arizona Department Game and Fish, have located a number of sites with small groups of C. townsendii, but none with large aggregations (S. Castner pers. comm.). All surveys by AZ Game and Fish have been conducted below snow line, in areas that experience prolonged periods of above freezing winter temperatures. Limited surveys by J. Bain (pers. comm.) at higher elevations have not revealed hibernating sites. Information on Arizona compiled by E. Pierson, relying primarily on information supplied by V. Dalton, J. Bain and Arizona Department of Game and Fish. BRITISH COLUMBIA C. townsendii from the coastal areas and Vancouver Island are considered to be C. t. townsendii and those from the inland areas C. t. pallescens (Handley 1959). C. townsendii is known in Canada only from southern British Columbia. There are relatively few historic records: a few for C. t. townsendii from Vancouver Island, the Gulf Islands, and the Vancouver area, and a few for C. t. pallescens from the south central portion of the province, as far north as Williams Lake (Handley 1959, Nagorsen and Brigham 1993). The only known maternity colony in British Columbia (Nagorsen and Brigham 1993) is in the attic of a house and contains about 60 females. The young appear to be bom mid-July. Lactating females have been mist netted in the Williams Lake area in the summer, but so far no maternity roosts have been found (Roberts and Roberts 1993). Although this bat is consistently found hibernating in British Columbia, the aggregations are generally small (Nagorsen and Brigham 1993). A colony of 20 to 40 is known from a cave on Thetis Island. In the interior, small colonies of up to 16 individuals have been found in mines and caves in the Okanagan Valley and the Williams Lake region. Recent surveys in the Williams Lake area have identified seven hibemacula, with only a few individuals per site (Roberts and Roberts 1993). Temperatures in hibernating sites are generally 5-8 ”C, although hibernating bats have been found with ambient temperatures of -4“ to -7'C (Nagorsen and Brigham 1993). Information on British Columbia compiled by E. Pierson. CALIFORNIA Both subspecies of C. townsendii are present in California (Handley 1959). The majority of the state is a zone of intergradation for both subspecies, although C. t. townsendii is found 15 primarily along the coast from Santa Barbara north, and C t. pallescem is the only subspecies found in the southeastern portion of the state (Handley 1959). This species, considered a Mammal of Special Concern by the California Department of Fish and Game, and has no special status with either the U. S. Forest Service (USFS) or BLM. Recent surveys conducted by Pierson and Rainey (1994) for California Department of Fish and Game show marked population declines for both subspecies. Over the past 40 years, there has been a 52% loss in the number of maternity colonies, a 45% decline in the number of available roosts, a 54% decline in the total number of animals, and a 33% decrease in the average size of remaining colonies for the species as a whole across the state. The status of particular populations is correlated with amount of disturbance to or loss of suitable roosting sites, not with subspecific status. The populations that have shown the most marked declines are along the coast (most likely C. t. townsendii), in the Mother Lode country (within the zone of intergradation), and along the Colorado River (C. t. pallescem). A comparison of former and current population estimates for 18 historically known maternity colonies shows that six colonies (33 %) appear to be extirpated; six others (33 %) have decreased in size; one (6 %) has remained stable; and five (28 %), four of which are protected within national parks (Lava Beds and Point Reyes National Seashore), have increased. A comparison of colony size for historically and currently known colonies, indicates that mean colony size has decreased from 165 (n = 18) to 111 (n = 34). The median colony size has decreased from 100 to 75. There are currently 38 known maternity colonies, occupying 55 known roost sites, with an estimated total population of about 4,300 individuals. Only three of these colonies have adequately protected roost sites. Hibernating C. towmendii have been found historically or during a recent survey (Pierson and Rainey 1994) at 44 sites (24 in mines, 19 in caves, one in a building). Most of these sites contain fewer than 20 individuals. Only three hibernating colonies number more than 100. The most significant aggregations (all those with > 100) occur in the most northern part of the state, particularly Siskiyou County. In other areas, particularly the desert, smaller aggregations (5-20) are more typical, although mine shafts, found by S. Altenbach (pers. comm.) to house the largest aggregations remain essentially unexplored in California. Four additional hibernating sites, not considered by Pierson and Rainey (1994) were located in 1979 (Marcot 1984), one of which contained 40-50 individuals. Information on California compiled by E.D. Pierson. COLORADO According to Handley (1959), all populations in Colorado would be C. t. pallescem. The species is listed as a species of Undetermined Status by Colorado Division of Wildlife, as a 16 Sensitive Species by the USFS, and as a Species of Special Concern by BLM. Current known historical records for C townsendii from Colorado number only about 200 individuals. Of these 97 are from 1990 or later. Little is known of historical roost sites in the state. Only eight maternity roosts have been identified for Colorado. Four, all in caves, were documented pre-1970. Four, three in mines and one in a cabin, have been discovered since 1970. Seven of these sites contain 1-8 adult females. The largest known roost, in a mine, contains 75-80 adult females. In addition, there are three potential maternity roost sites, two in caves and one in a mine, which will be verified in the 1995 field season. Historic colony size is unavailable for any of these sites, but if these colonies attained sizes typically found in other portions of the species’ range, then dramatic declines have occurred. All caves receive heavy visitation except for one, which is on private property. This last cave supported the largest number of bats, 26. A maternity site (ca. 50 animals) was found in a small cave in Clear Creek Fault Canyon in the early 1960’s. Within a few years of the publication of a guide book to the caves of Colorado, human visitation to the cave increased, and this colony disappeared (S. Altenbach pers. comm.). Thirty hibemacula have been documented. Four were known prior to 1990; 25 have been found since 1990. Most hibemacula documented in Colorado are small, with only a few animals per site. A roost of 200 individuals was found in a mine during January, 1990. The landowner reports that in 1995 the colony had only about a dozen bats. Hubbard’s Cave was discovered to have a colony of 500 hibernating C. townsendii in December 1968 (S. Altenbach pers. comm.). This cave, which receives heavy visitation in the summer, is basically inaccessible during the winter, and may still harbor a large hibernating population, although current numbers are unknown. A survey in the fall of 1994 indicated, based on the presence of some individuals, that the cave is still being used by C. townsendii. There are about six additional winter records for C. townsendii which lack specific locality information. Information for Colorado was supplied by K. Navo. IDAHO Figure 2 illustrates known locations for C. townsendii in Idaho. According to Handley (1959) most of the state is a zone of intergradation between C. t. townsendii and C. t. pallescens. C. townsendii is listed as a Species of Special Concern, Category C (undetermined status species) by the Idaho Department of Fish and Game. This listing prohibits the take or possession of the species. C. townsendii is listed as a Sensitive Species by the BLM in Idaho and Regions 1 and 4 of the USFS. Two maternity roosts were identified in 1994 in lava-tube caves at Craters of the Moon 17 Figure 2. Known locations for Corynorhinus townsendii pallescens in Idaho. The star indicates the only known location of maternity colonies in Idaho; triangles with dates, indicate museum specimens, recorded in the Idaho Museum of Natural History, Pocatello, REGIS-MAMMALIAN DATA BASE, developed from information collected from 32 U.S. museums; squares, indicate net release sites/with voucher specimens collected; dots, areas of recent research. 18 1947-89 National Monument in southeastern Idaho; one site had about 40 individuals present the other between 40 and 50 individuals present (Keller and Saathoff 1994). There are no other historical records or accounts of maternity colonies in the state. Surveys of hibemacula on the Shoshone BLM District in south central Idaho (Lewis 1994) showed a 59% reduction in total bat numbers (C. townsendii being the dominant species) since a 1987 inventory (Wackenhut 1990). The three largest hibernating populations showed the following reductions: Gypsum cave contained over 250 bats in 1987 and 51 bats in 1994, Giant Arch contained over 400 bats in 1988 and 165 in 1994, Bat cave contained 300 bats in 1988 and 128 in 1994. Many of the lava tube caves used as hibemacula on the Shoshone BLM District are popular recreational caves. Hibernating populations on the Idaho National Engineering Laboratory (INEL) appear to be stable. (B. Keller pers. comm.). Recreational caving is not allowed on the INEL. Recent surveys in Bear Lake County (B. Lengas pers. comm.), conducted between March and November 1993 identified a small hibernating population (22 animals) in Minnetonka Cave. This cave is open to the public as a commercial cave in the summer, and has no summer bat population. Four nearby adits were also occupied by one or two C. townsendii, two in the winter, one in the summer, and one year round. Three additional adits in Bear Lake County had single hibernating C. townsendii. Additional roost sites have recently been identified throughout Idaho in mines and caves (B. Keller pers. comm., L. Lewis pers. comm., P. Perletti pers. comm.), including a lava-tube cave (Niter Ice Cave) on private property in Caribou County with 50 hibernating C. townsendii (M. Wackenhut pers. comm.). No trend information is yet available for these sites. Two mines and two lava-tube caves are gated in Idaho to conserve local bat populations. Information for Idaho supplied by B. Keller, B. Lengas, L. Lewis, P. Perletti and M. Wackenhut. KANSAS According to Handley (1959), all populations should be C. t. pallescens. This species is well known from the gypsum caves of Barber and Comanche Counties in south central Kansas. Maternity, hibernating and summer male populations are known to occur here (Humphrey and Kunz 1976). Band injuries, reduction in size of a maternity roost, and abandonment of a maternity roost (resulting from disturbance during a study lasting from 1968 to 1971) have been reported (Humphrey and Kunz 1976). Current information on the status of this species in Kansas is not available. Information for Kansas supplied by S. Altenbach. 20 MONTANA C. townsendii has been found at locations in western and south-central to eastern Montana. Only north-central Montana (Hi-Line) is without record of occurrence. The primary subspecies is C. t. pallescens. There is a possible zone of overlap with C. t. townsendii in the southwestern portion of the state. C. townsendii is listed as a Species of Special Concern and considered quite rare (especially colonies) by Montana Natural Heritage Program (MTNHP). It is considered a Sensitive Species by the USFS, and an unprotected nongame species by Montana Department of Fish, Wildlife and Parks. The only protective status for bats in Montana is provided through "Sensitive Species" status on USFS lands and through the Federal Cave Resources Protection Act. Four maternity roosts are known: Lewis and Clark Caverns State Park (125-175 females); a private hard rock mine within the Flathead Indian Reservation (75 females); two limestone caves along Jefferson River (50 females). At least 12 hibemacula are known. Most contain only a few individuals. Mystery Cave (BLM-gated) holds 50-100 C. townsendii and varying numbers of Myotis spp.\ a private hard-rock mine in western Montana contains 60-120 (this mine will be gated). A popular cave in central Montana contained approximately 30 hibernating C. townsendii (T. Butts pers. comm.). A winter survey of the Pyror Mountains identified several caves with 5-25 individuals in each. Most other winter locations are 1-5 individuals in small mines or caves. The Department of State Lands (DSL) has administered an ambitious abandoned mine closure program for several years. Unfortunately, several known or potential C. townsendii hibemacula were destroyed (mostly abandoned coal mines). In 1994 the Abandoned Mine and Reclamation Bureau developed an agreement with the MTNHP to review mines slated for closure. This arrangement has been very successful with several mines recommended for bat gating in the first year. DSL has expressed a willingness to work with private mine owners to provide funding and logistical support to gate their adits. A DSL-sponsored workshop in 1995 will bring together federal and state agency staff for review of the bats and abandoned mine program (put on by Bat Conservation International, Inc. (BCI) and MTNHP). Recent field studies have confirmed 10 locations for C. townsendii in three years. Field studies on C. townsendii continue to be coordinated through the Natural Heritage Program. All location data and reports are incorporated to their database files and available for project review and conservation planning (data security and release based on normal procedures for threatened and endangered species). Information for Montana supplied by D.L. Center. 21 NEBRASKA According to Handley (1959), any C. townsendii in Nebraska would be C. t. pallescens. There is only a single record for C. townsendii, probably C. t. pallescens (Handley 1959) from Nebraska. This specimen was a male, found hanging on a screen door in Sheridan County on October 5, 1972. Unless other records have been reported this species should be considered an unlikely resident in Nebraska. Information for Nebraska was supplied by S. Altenbach. NEVADA According to Handley (1959), central and southeastern Nevada populations would be C. L pallescens and northwestern Nevada is part of the intergradation zone between the C. t. pallescens and C. t. townsendii. This species receives no state protection. Ports and Bradley (1995) have been collecting information on C. townsendii in northeastern Nevada since the early 1980’ s. In that time they have identified three maternity roosts (30-40 females in one roost, and unknown numbers in the others) for a 37,000 square mile area (P. Bradley pers. comm.). Reproductively active C. townsendii (both male and female) have been found at 5 out of 30 sites (17%) surveyed during the breeding season. Three of ten cave/mine sites (33%) were confirmed C. townsendii maternity roosts. During this same survey period C. townsendii ranked 4th in relative abundance (individuals/total) of 12 species captured. Thirty C. townsendii individuals were captured in 296 hours of mist/harp trap surveys (0. 1 bats/hour) and C. townsendii individuals were captured at 10 of the 30 sites (33 %) sampled. Most of these were non-reproductive males (Ports and Bradley 1995). A 1966 survey of caves in eastern Nevada (Soulages 1966) identified 16 bat caves, and supplies population estimates for many of these. Unfortunately, survey dates are rarely supplied, making it difficult to distinguish between maternity and hibernating sites. At least two caves had significant maternity colonies (80-100 individuals in one, 150-200 in the other). One cave was identified as a hibernating site, and one as having a year round population. One of the maternity sites. Old Man Cave, was resurveyed in the summer of 1993 (B. Lengas pers. comm.) and 1994 (P. Bradley pers. comm.), and found to contain 15 adult C. townsendii in 1993 and ca. 30 in 1994, a decline from the 80-100 individuals (40-50 adults if surveys were done after young were identifiable in the colony) found in 1966. Seasonal use restrictions have been implemented at this cave by the USES. Another cave, just north of Old Man’s Cave has a maternity colony of 15-20 females. The abandoned mine program in Nevada is administered by the Nevada Division of Minerals (NDOM). Three thousand mines were closed prior to 1994 without wildlife surveys. The NDOM is now providing the Nevada Department of Wildlife (NDOW) with mine locations 22 prior to closure. Mine closure protocol is now being developed by an interagency team. No information is available on gating of mines in Nevada, although the NDOM has sanctioned barbed wire fencing to relieve liability. Information for Nevada was supplied by P. Bradley and B. Lengas. NEW MEXICO According to Handley (1959), all populations in New Mexico would be C. t. pallescens. This species receives no state protection. Since 1991 a cooperative program between the University of New Mexico and the New Mexico Abandoned Minelands Bureau has evaluated over 300 mines for bat use. About 45 percent of the abandoned mines surveyed to date have some form of bat use, and about 90 percent of those are occupied by C. townsendii. The majority of the mines used by C. townsendii are hibemacula for 1-50 (1-5 most frequent) individuals. One mine has between 1(X) and 300 individuals, and another about 100. The Black Canyon Mine in Socorro County was evaluated in October of 1992 and found to have very large numbers (probably several thousand). In early November of that year a cursory evaluation of only one of several levels revealed over a thousand torpid bats. Between that time and early February of 1993 the timbers of the mine’s 300 foot shaft were burned, probably by vandals. About 100 bats survived in the adit that served as an air intake, but it is likely that all others died. The majority of the mine is now inaccessible, and the full impact of the fire will never be known. Between 100 and 200 bats continue to use the adit level as a hibemaculum. Seven maternity colonies of this species are known in abandoned mines. One has 300-500 animals, one has about 100, and five have between 10 and 50. A colony in the Black Canyon Mine in Socorro County was probably very large before the fire in 1992-1993, but now numbers only about 25 individuals. In addition, two maternity colonies are known from caves: one of over 1,000 individuals was reported in a cave on the El Malpais National Monument in May, 1991 (B. Rogers pers. comm.), and another of between 50-100 is reported from a deep vertical cave in Dona Ana County. One bachelor colony of about 75 individuals and five intermediate (post hibernation) roosts with 5-25 individuals are also known in mines. To date 44 bat-compatible closures have been installed on mine entrances. These are primarily bat gates, but include a few cable nets with "bat windows". All entrances on gated mines that are not used by bats have been secured with closures that maintain airflow. At present 24 additional bat compatible closures are in design or preconstruction phase. Time limitation has permitted a follow up on only a few of the mines that have been gated. 23 Populations in all appear stable, and one, a hibemaculum, has had a population increase (survey in January 1995) from 100 to about 200 individuals. Another, a maternity colony, has a much larger yearly guano accumulation beneath the roost than before gate installation. A hibernating colony of "several thousand" bats in Fort Stanton Cave in Lincoln County was vandalized in the 1970’s and in 1991-1993 had between 850-1000 individuals. About 300 bats were present in 1994-1995. Even though this cave has been gated, the gate is repeatedly violated. Other caves in the region have winter populations in the low hundreds but were reported to have far higher populations over the last 10 to 20 years. A remote lava tube cave in central New Mexico, which had about 4(X) hibernating individuals in 1980, now has 130. Many limestone, fault and lava caves around the state have hibernating populations which typically number from one to 10, and a few with as many as 50 individuals. Although data on populations in these caves are scarce or anecdotal, there are no examples of increases, and declines of 10 to 100 percent over a 20 year period are estimated in several. One barrier to understanding the status of this species in New Mexico is mistrust between the biological and caving communities. Parts of New Mexico contain hundreds of caves which almost certainly contain hibernating, maternity, bachelor and intermediate colonies of this species. Although the majority of the caving community is cooperative and responsible, some are hesitant to inform anyone of the presence of bats which they encounter in caves because they fear that the caves may be closed to recreational activities. Major threats to this species in New Mexico are recreational use and vandalism of caves and abandoned mines by the general public. An additional threat is the closure of abandoned mines by private landowners or by claim and patent holders. The New Mexico Abandoned Mine Lands environmental assessment program is the most progressive in the nation and does not present a threat to this species. Information for New Mexico was supplied by S. Altenbach. NORTH DAKOTA No information is available, but Hall (1981) suggests C. townsendii could be found here. OKLAHOMA According to Handley (1959), all populations in the western comer of Oklahoma should be C. t. pallescens, and those in the extreme northeastern part of the state should be C. t. ingens. Populations in the central portion of the state are in a zone of intergradation between C. t. pallescens and C. t. ingens. C. t. pallescens is well known from the western half of the state, where it forms maternity. 24 hibernating, and bachelor colonies. The majority of roost sites in the western pjirt of the state are in caves, although there are few abandoned mines in this part of the state apparently occupied by this species. Recent surveys of the gypsum caves in the western part of the state (W. Caire pers. comm.) suggest a marked decline in numbers over the last 20 years. A survey of 70 caves in this region located only 90 individuals. A maternity colony in Alabaster Caverns, formerly numbering about 100 individuals, is now estimated at 20 to 30 individuals. Information on this subspecies is limited by the amount of time and funds allocated for surveys, and by difficulty in obtaining information on bats from members of the caving community. Information on Oklahoma supplied by S. Altenbach. OREGON Both subspecies of C. townsendii are present in Oregon (Handley 1959). The populations in the western part of the state are considered to be C. t. townsendii. The remainder of the state is a zone of intergradation for both subspecies. This species is proposed for listing as threatened or endangered by the State Department of Fish and Wildlife. It is on the sensitive species list for BLM and Region 6 of the USFS. Six significant maternity colonies of C. townsendii have been identified in Oregon (Cross et al. 1976, Perkins and Levesque 1987, Cross and Waldien 1994), ranging in size from 150 to 400 females. These are located in Curry, Deschutes/ Jefferson, Douglas, Jackson/Josephine, Malheur, and Wallowa Counties. Large hibernating populations (130 to >300 individuals) are known from the mountains and the east side of the Cascades in Grant, Deschutes and Malheur Counties. A number of other hibernating sites have been located throughout the state, but, in areas with moderate winter climates, these colonies typically have no more than 30 bats. Population declines have been documented for western and central Oregon colonies. Perkins (1990) most recent summary documents that between 1980 and 1990, three maternity colonies were extirpated, four populations showed declines of between 30 and 53%, six appeared stable, and one showed a 16% increase. Two populations located on the north coast believed to be extirpated were relocated using old bunkers as hibemacula. Most populations are on federal lands. All population declines are known to be due to human disturbance of roost sites. Recent counts indicate total numbers for the state between 2,500 and 3,000 individuals. Information for Oregon supplied by J.M. Perkins. 25 SOUTH DAKOTA According to Handley (1959), all populations in South Dakota should be C. t. pallescens. All recent research on C. townsendii in South Dakota has been focused on the Black Hills. Three relatively small maternity roosts are currently known, two with about 50 animals each, and one with about 35 animals (J. Tigner pers. comm., Tigner and Aney 1994). The current status of a nursery colony in a small sandstone cave in Fall River County, from which 40 bats were taken in July 1968 (Turner and Jones 1968), is unknown (J. Tigner pers. comm.). Private industry was responsible for the closure of over 100 mines without biological survey at one mine site in South Dakota (J. Tigner pers. comm.). Information on South Dakota compiled by E.D. Pierson, and supplied by E. Stukel and J. Tigner. TEXAS According to Handley (1959), western Texas is a zone of intergradation between C. t. pallescens and C. t. australis, and northern Texas a zone of intergradation between C. t. pallescens and C. t, ingens. Schmidly (1991) reports that this species occupies gypsum caves in the northern part of its range in Texas, and caves and mines in the Trans-Pecos. The Mariscal Mercury Mine complex in Big Bend National Park, Brewster County, was found to house a maternity colony of many hundreds of individuals and was used as a hibemaculum for the species as well (Altenbach 1994). Multiple entrances to the mine complex were originally closed in the 1980’s by the National Park Service, using a variety of materials to block human access. Fortunately the closures were crude enough to allow bat access through some of the openings and the colony persisted, although predation by Bassariscus occurred in restricted openings. This complex is now secured with appropriately designed bat compatible closures. As a consequence the colony and habitat are now protected. Only the action of the Park Service in evaluating this habitat prevented its final and destructive closure. This incident illustrates the threat posed by mine closures and raises the question of the consequence of other mine closures in the region. Abandoned mine evaluation in Guadalupe Mountain National Park, Texas, found evidence of maternity, hibernation, and post-hibernation use by C. townsendii. All mines that had use, or potential for use, were secured with bat-compatible closures. Information on Texas supplied by S. Altenbach. UTAH Most C. townsendii populations in Utah are assumed to be C. t. pallescens (Handley 1959), 26 with a possible small zone of intergradation with C t. townsendii in the northwest comer of the state. C. townsendii is listed as an S2 species (a species of special concern because of limited distribution and habitat) by the Utah Division of Wildlife Resources, and a sensitive species by the USFS and the BLM. There are five currently known maternity sites in Utah: three caves and two mines, with populations ranging in size from 15 to >200 females. The two most important sites have evidence of serious disturbance. Bat Cave is located near a Boy Scout camp. Although the Boy Scouts leaders have discouraged their scouts from visiting the cave since 1991, disturbance apparently continues (B. Lengas pers. comm.). Ninety dead bats, presumably killed by boy Scouts were found by B. Lengas in the summer of 1991, with 100 bats occupying the cave in September 1991. In April 1992 ca. 200 C. townsendii were occupying the cave. In September 1993, 46 dead juveniles, and 245 live C. townsendii were found (B. Lengas pers. comm.). Logan Cave (B. Lengas pers. comm.) is visited by at least 15,000 people each year and the C. townsendii numbers fluctuate from month to month due to human disturbance. In June 1992, B. Lengas found ca. 30 females in the cave: in June 1993 no bats: in June 1994 75 females (after closure by the Forest Service from October 1993 to June 1994). Surveys by the Uinta National Forest collected information on at least four additional likely maternity populations for C. townsendii. A mine complex with large guano accumulations likely attributable to a maternity colony of C. townsendii was located in October, 1994, in the Spanish Fork District of the Uinta National Forest. The presence of this colony will be confirmed during the 1995 field season. Reliable observers also report that a large colony (possibly in the thousands) of C. townsendii roosted in circular clusters in a mine complex in the Lone Peak Wilderness area east of Alpine, Utah. These mines were closed in July and August, 1991, likely entombing the bats. Another mine near Elberta, Utah reportedly had bats covering the ceiling for 3/4 of the length of a 1.5 mile long adit. C. townsendii was identified as one of the species in this mine. The mine was closed in 1989 by the local sheriff with the bats inside. Another mine in Rock Canyon east of Provo has historic records of heavy bat use. The site receives heavy human visitation during the spring and summer months, and during the summers of 1993 and 1994 only a single female was found in this mine. B. Lengas (pers. comm.) reports four small hibemacula (3 to 24 individuals) in Utah: three in caves and one in a mine. At Logan Cave, numbers appear to have declined recently from 13 in February 1992 to three in February 1994. D. Stricklan (pers. comm.) has identified 18 mines on the Pleasant Grove District of the Uinta National Forest as active hibemacula for C. townsendii. Colony size varies from one to 30+ individuals. There are ten other historically known maternity and hibernating colonies which no longer exist (three in caves, six in mines, one in a building), and two for which the exact locality is unknown. Five of these sites (one cave, four mines) have been sealed to exclude bats, and four (two caves, two mines) receive very heavy human disturbance. The one building site 27 has been abandoned for unknown reasons. Mine closures under the Abandoned Mine Program, administered by the Division of Oil, Gas, and Mining (DOGM) likely pose the greatest threat to C. townsendii populations in Utah. The DOGM has no written policy concerning mine closures and sensitive wildlife. At least 3,000 mines have been closed since 1985, some of which contained bats visible from the entrance. If the species occur in coal mines with roughly the same frequency as in hard rock mines (70%), then it is likely a number of C. townsendii, both individuals and colonies, have been sealed in through mine closure. Although no formal surveys were done, at least 66 of the 3,000 mines were known to contain bats (D. Stricklan pers. comm.). To date, the USFS has been conducting pre-closure bat/mine surveys only in the Pleasant Grove and Perron Ranger Districts (C. Bums pers. comm., D. Stricklan pers. comm.) Information for Utah was supplied by B. Lengas, R. Sherwin and D. Stricklan. WASHINGTON Both subspecies of C. townsendii are present in Washington (Handley 1959). The populations in the western part of the state are considered to be C. t. townsendii. The remainder of the state is a zone of intergradation for both subspecies. This species is a state candidate for listing as threatened or endangered. For two populations both maternity and hibernating sites have been located (Perkins 1990). One population, near Mt. St. Helen’s has doubled in size since the eruption in 1980, due to lowered human disturbance in the area. This population, currently at about 350 females, nevertheless, has about 50% fewer animals than in the 1960’s (Perkins 1990). The other population, near Mt. Adams, has increased by about 5% in the last 10 years, and has stabilized at about 250-275 females. Two additional maternity sites have been identified in abandoned buildings, in Lincoln County, along the Columbia River. The hibernating populations associated with Mt. Adams and Mt. St. Helens are both large (>200 animals). Smaller hibernating populations are known from a few other areas, including Whatcom (near Bellingham), Asotin, and Yakima Counties (Perkins 1990). A maternity colony of ca. 100 C. townsendii was located in Boulder Cave on the Naches River in July 1930 (Scheffer 1930). The population in this cave numbered 81 in a 1994 winter count (M. Perkins pers. comm.). The road to this cave is now gated and patrolled. The identified populations for the state now total about 600 animals, although much of the state has yet to be surveyed. Information for Washington supplied by J.M. Perkins. 28 WYOMING All Wyoming populations are C. t. pallescens. This species is a USFS Region 2 and Region 4 Sensitive Species. It is also considered a Species of Special Concern (SSC)2 by the Wyoming Game and Fish Department (WGFD). The SSC2 category includes species for which populations are declining or restricted in numbers and distribution, and which are experiencing on-going loss of habitat. Also, Wyoming Game and Fish Commission Nongame Wildlife Regulation, Section 11, prohibits intentional take of C. townsendii and all other bat species, except as approved by WGFD to address public health concerns. Three maternity sites (numbering 46, 50+ , and 2(X)+ individuals) are known for C. townsendii in Wyoming (one in an abandoned gated mine, and two in caves). There is little historical data on bat numbers or locations, and no pre-1994 information on classification of caves or abandoned mines as to bat presence or habitat potential. Fifty-nine caves and 17 abandoned mines were surveyed between May and October 1994. Twelve sites were occupied by C. townsendii at the time of the survey, which included at least one or, in most cases, two nights of mist netting the entrance, and a daytime interior survey. Of the 12 sites occupied, six were night roosts of one to two C. townsendii, two were both day and night roosts of one to three C. townsendii. Two sites were classified as hibemacula with one and three C. townsendii, respectively. Two sites were maternity colonies, estimated at 50+ females and 200+ females, respectively. Both were counted during brief interior surveys, and mist netting was not conducted. Information for Wyoming was supplied by B. Luce. THREATS SUMMARY OF THREATS Threats facing C. townsendii can be categorized into those threats that are primarily human-induced (anthropogenic) and those resulting from natural events and/or the ecology of the species. Threats can further be categorized as those with the potential to affect C. townsendii habitat (roosting, foraging, or migration corridor habitats) and those that would have the potential to cause direct C. townsendii population declines with no disturbance of habitats. All threats have the potential to affect either roosting, foraging, or migrating segments of the population. Many threats are interrelated, and it was not the intent here to down play their connectivity, but rather to make the document as usable as possible. Overall, the most serious factor leading to population declines in bats, including C. townsendii, is loss and/or disturbance of suitable roosting habitat (Tuttle 1979, McCracken 1988, Perkins 1990). Loss and/or degradation of foraging habitat may also be a contributing 29 factor in the declines of C. townsendii populations (Pierson and Rainey 1994). C. townsendii roost fidelity, longevity and low reproductive capability all combine to intensify any negative effects of anthropogenic threats to the species. ANTHROPOGENIC THREATS Abandoned Mine Closures During the 1980’ s, thousands of abandoned mines were closed in the west with no input from wildlife professionals (P. Bradley pers. comm., B. Luce pers. comm., K. Navo pers. comm., D. Stricklan pers. comm., Belwood and Waugh 1991, Brown and Berry 1991, Pierson and Brown 1992). In many states, mines represent a substantial portion of the suitable roosting habitat available to C. townsendii and act as substitute habitats in areas where intense recreational caving and vandalism have made natural roosts unsuitable. In some areas (e.g., the desert areas of California and portions of New Mexico) almost all known roosts are in mines (S. Altenbach pers. comm., P. Brown pers. comm., Pierson and Rainey 1994). Several thousand C. townsendii have been found in one abandoned mine in New Mexico (S. Altenbach pers. comm.). Closure of abandoned mines for hazard abatement is typically accomplished by either fencing, signing or blasting closed/bulldozing/sealing all openings with barriers such as soil/rock or block walls. In addition to the loss of suitable roosting habitat, the closure may result in a direct loss of bats if done in such a manner that bats are trapped inside the mine. Although a limited number of mine workings serve as significant bat roosts, the cumulative effects of closing many small roosts as well as a few large roosts may be devastating to C. townsendii populations in the west. In some states, the presence or absence of historic mining activity within contemporary mining districts have, in the past, had little impact on the decision making process in terms of wildlife related issues. Also, the activities of state sponsored AML programs have, in the past, not included wildlife inventories and recommendations in their closure programs. Recreational Caving Interest in recreational caving is increasing in America. Current membership in the National Speleological Society (NSS) is approximately 11,500, a 28% increase from 1991 (J. Gurnee pers. comm.). Most NSS cavers support cave conservation (NSS News, July 1994), and many agency cave managers have excellent working relationships with NSS groups ( R. Alward pers. comm., K. Baldino pers. comm., M. Bilboa pers. comm., B. Boggs pers. comm., B. Edmonsen pers. comm., J. Goodbar pers. comm., J. Neiland pers. comm., P. Perletti pers. comm.). Along with the obvious benefits that educated, conservation minded cavers offer to cave management come the undeniable negative impacts that increased roost visitation has on sensitive bat species. C. townsendii 's sensitivity to human disturbance of roost sites is well documented (Pearson et al. 1952, Graham 1966, Stebbings 1966, Mohr 30 1972, Humphrey and Kunz 1976, Stihler and Hall 1993, Pierson and Rainey 1994). C. townsendii maternity and hibernation roosts that experience increased visitation rates during critical use periods experience concomitant losses in colony populations. Graham (1966) blamed the abandonment of several maternity sites by C. townsendii in California on the repeated visitation by people due to the popularity of the caves. Barbour and Davis (1969) also attributed the increase in abandonment of maternity sites throughout the species’ range to an increase in spelunking activity. Pierson and Rainey (1994) have shown that those colonies with the greatest population declines also experience frequent disturbance. A long term study of a number of cave roosts in West Virginia (Stihler and Hall 1993) has shown that excluding humans from roost sites by gating or fencing has resulted in increases in C. townsendii populations. When gates have been breached, populations have dropped precipitously, and been slow to recover. For example, following protection, one colony increased over a three year period from 739 to 1,137 bats. The summer after the cave was illegally entered, the colony numbered only 286, and four years later had only recovered to ca. 40% of it pre- vandalism levels. A notable distinction exists between most NSS cave groups and non-affiliated recreational cavers, the flashlight explorers who have little or no understanding of cave resources (J. Nieland pers. comm.). Uninformed and/or misinformed spelunkers present a significant threat to bats and bat habitat. It is not uncommon to find roosts littered with dead bats, obviously killed by humans (Mohr 1972, Tuttle 1979, Pierson and Rainey 1994). S. Altenbach (pers. comm.) reported that several thousand C townsendii were killed in an arson mine fire in New Mexico in 1992. Baldino (pers. comm.) reported that an individual was seen shooting a high powered rifle into a T. brasiliensis day roost (approximately 80,000 bats) in Nevada in 1993. These unrelated incidents underscore the extreme susceptibility that aggregated bat populations have to injury by an uninformed and or misinformed general public. The negative impacts to C. townsendii populations are further exacerbated by agency promotion of recreational caving. Public land cave locations are often included on agency maps that are dispersed to the public. The USGS has traditionally included cave locations on the 7.5 minute series (topographic) maps. Cave locations have been freely dispensed upon inquiry to civic groups, the media, and the general public. These factors, together with improved and increased road networks, have made many caves with bat habitat easily accessible to the general public, thus increasing roost visitation and potential harassment. Agencies have frequently placed gates on caves to control recreational use and protect cave resources. Gates have been installed that are not built to bat specifications, making the cave unsuitable habitat. Some elements of the caving community have observed agency cave management and have withheld information about cave locations or cave resources out of fear of increased regulation or poor management. Barriers to communication between cave managers and cave user groups could contribute to further losses in bat habitat. 31 Renewed Mining at Historic Sites Much of the contemporary open pit gold mining in the west is associated with historic hard rock mining districts. Historic underground workings (shafts, adits, stopes, etc.) sometimes become incorporated into current open pit mining plans of operation (Belwood and Waugh 1991, Brown et al. 1993, Brown unpubl. obs.). Eventually, older hard rock mines are shaved away by the newer open pits. C. townsendii roosts have been lost under these circumstances (Pierson and Rainey 1991, Pierson and Rainey 1994). At times, limestone solution caves were incorporated into the workings of historic hard rock mines (M. Wilkins pers. comm.). Open pit mining in these sites could destroy natural caves as well. Toxic Material Impoundments Cyanide is used in the processing of gold ore. A cyanide solution is sprayed on gold bearing ore and later collected in ponds of varying size. These ponds often contain lethal levels of cyanide and heavy metal compounds. At times, lethal concentrations of cyanide also become ponded atop ore piles. In Nevada, 15 mines reported killing at least 158 bats (species not identified) between 1986 and 1989 in their cyanide solution ponds (NDOW Files). Regulations designed to eliminate this source of mortality through netting and neutralization were established in April 1990 and reported mortalities decreased significantly as a result. A troubling unknown is how many of these mortalities go undetected and thus unreported; particularly those mortalities that result from bats using ponded water atop ore piles. Also, as before mentioned, much of the contemporary open pit gold mining in the west is associated with historic mining districts. Locating toxic water sources in close proximity to established C. townsendii roost sites may be a deadly consequence of these associated land uses. This problem may be particularly severe in desert areas, where water associated with mining operations may be the only available water in an area. Oil reserve pits associated with oil drilling operations can be a source of bat mortality (B. Luce pers. comm.). Bats have been found dead at these ponds and additional mortalities probably go undetected and unreported. Locating these pits near roost sites may result in increased losses. Pesticide Spraying C. townsendii forages primarily on moths (Ross 1967, Whitaker et al. 1977, 1981, Dalton et al. 1986, Perkins eind Schommer 1991, Sample and Whitmore 1993). Non-target, insecticide sprays reduce the number and quality of insects in an area available to C. townsendii (Brown and Berry 1991) and have been identified as contributing to the decline of North American bat populations (Clark 1981). Non-target lepidopteran sprays, used to control gypsy moth outbreaks may reduce moth populations in specific spray sites for years. B.T. {Bacillus thuringiensis) sprays may suppress Tussock moth and spruce budworm 32 reproduction enough to suppress one or two years of C. townsendii reproduction in project sites (Perkins and Schommer 1991). Non-target Lepidoptera studies in the East, examining the effects of B.thuringiensis sprays and gypsy moth defoliation on the food source for C. t. virginianus concluded that both defoliation and control measures could have an impact on the food base. B.thuringiensis applications reduced species richness and abundance of larval and adult non-target Lepidoptera and richness and abundance of some larval and adult Lepidoptera were also reduced in the defoliation plots (Sample et al. 1993, Sample and Whitmore 1993). Impacts to the larval stage are seen the year of B.thuringiensis application while adult population impacts may also be seen the same year or observed the following year. Non-target research has also been conducted with the insecticide diflubenzuron (Dimilin). Dimilin is an insect growth regulator which inhibits chitin synthesis. It is detrimental to immature or larval insects but is generally not lethal to adult insects. Dimilin has been shown to produce significant indirect effects by reducing the food available to bats (Sample et al. 1993). Impacts to the larval stage are seen the year of Dimilin application, while adult impacts can be seen the same or following year. Insecticides primarily used in large scale spray projects in agricultural or range settings are malathion and carbaryl. These are broad scale insecticides and impact numerous species of insects. Each year, thousands of acres are chemically treated across the western U.S. to control insect pests. It is difficult to assess what impact these sprays are having on insectivores in general. However, impacts could be significant in target spray areas where large amounts of the prey base are being removed. In addition to the direct effects on the food source of bats, temperate region bats may also be at risk of direct poisoning by insecticides as a result of their diets, high metabolic rates, high food intake, and high rates of fat mobilization during migration, hibernation and lactation (Clark 1988). Vegetative Conversion Millions of acres of native shrub-steppe habitats have, through the agents of fire and mechanical and chemical vegetation manipulation, been permanently converted to monotypic exotic grasslands. Exotic annual bromes and wheat grasses account for the bulk of this conversion. Effects on Lepidopteran populations is unclear although most terrestrial forms are known to reproduce on shrubs, trees,and flowering plants, and not on grass species (S. Smith pers. comm.). 33 Livestock Grazing Livestock grazing practices have been responsible for large scale conversions of mesic riparian habitats to more xeric upland habitats across the range of C. townsendii. Limited data on foraging strategies of C. townsendii show a considerable site specificity and a preference for edge habitats between streams and mountain slopes (Clark et al. 1993). Much edge habitat disappears when riparian habitats are converted to upland habitats. It is unclear how this may have affected C. townsendii populations in the west. If C. townsendii are using these edge sites merely for their physical configuration, vegetation conversions may have had little impact on the species. However, if riparian vegetation is, for example, a critical component in the life cycles of preferred prey items, then long term vegetation changes may have had significant impacts on C. townsendii populations. For example, C. townsendii populations have shown a strong preference for Noctuid moths (Shoemaker and Lacki 1993). Noctuid moths are obligate users of lentic vascular hydrophytes {Tyha, Salix, Pontederia, Nuphar, Eichhomia, Polygonum) (Lange 1979). It follows that in regions where these host plant species have been lost or reduced, that the prey base has also been reduced for C. townsendii. Timber Harvest Twelve species of bats occur in the old growth forests of the Pacific Northwest (Christy and West 1993), and at least seventeen species in the forested regions of northern California (Rainey and Pierson 1993). Approximately 5% of the historic old growth forests remain standing in the northwest. In parts of the Northwest where rock cavities are uncommon, basal hollows in old growth redwoods may provide significant roosting habitats for cavity-roosting bat species such as C. townsendii. In two independent studies of bat use of redwood hollows in northern and central California, 100% were used by bats (Rainey et al. 1992, Gellman and Zielinski 1993). Where trees are used as day roosts, logging activities have been known to extirpate locally roosting bats during the work activities (Perkins 1991). Impacts may range from temporary displacement to elimination of potential roost sites. Additional losses of old growth timber may result in losses of C. townsendii populations in those areas where alternative roost sites do not exist. Inventory. Monitoring and Scientific Research Research activities can depress, scatter, or extirpate populations of C. townsendii (Pearson et al. 1952, Humphrey and Kunz 1976, Kunz and Martin 1982, Perkins and Schommer 1991). As previously cited, C. townsendii sensitivity to human disturbance of roost sites is well documented. For some of the same reasons that recreational caving can have a negative impact on C. townsendii, increased roost visitation by scientists can have similar effects. Human disturbance at C. townsendii maternity sites is a major concern. In one study, sampling at maternity roosts was blamed for a marked decrease in the sizes of the colonies; no 34 recovery was observed the following year, so sampling was discontinued. The authors concluded that visitation to nursery colonies could threaten the survival of C. townsendii in the Great Plains (Humphrey and Kunz 1976). Pearson et al. (1952) noted that repeated banding activities at maternity roosts caused the females to move to alternative roost sites, carrying their young with them. Hibernating C. townsendii are also easily disturbed. Twente (1955) noted that many bats left the hibemaculum as a result of banding, many of which were never recaptured. Pearson et al. (1952) and Humphrey and Kunz (1976) also noted increased winter movements by C. townsendii individuals to alternate hibemacula as a result of handling and monitoring during the winter months. Disturbance by humans of winter hibernation roosts can arouse bats from hibernation causing them to expend roughly 10-30 days of their body fat reserves during each arousal period (Tuttle 1991). Bats subjected to excessive disturbance during the winter months often run out of energy reserves and die of starvation prior to the arrival of spring. C. townsendii can be vulnerable to injury from wing banding (Humphrey and Kunz 1976, Pierson and Fellers 1994). Excessive collections for scientific purposes can also impact populations. In California, the Olema Inn Colony was almost entirely eliminated in one collecting effort (Pierson 1988). Often, the long term effects of collecting bats for scientific purposes are not known, but given the low reproductive potential of C. townsendii, they are likely to be damaging. This is particularly true where colonies have been subjected to repeated collections or where the series represent a significant proportion (>20%) of the population (Pierson 1988). Eradication In the past, state funded (Health Department) projects designed to protect the public from rabies transmission targeted the elimination of bat colonies. Little if any research went into determining whether or not target colonies were in fact reservoirs of the rabies virus. State agencies typically had a biased view of the incidence of rabies in bat populations as those bats that were brought in for testing were more likely to be the sick, easily caught individuals. It is unclear whether or not these policies are continuing in western states within the range of C. townsendii. State Status Classification and statute protection of C. townsendii varies from state to state. Western states classify certain segments of their mammal biota as unprotected. Some states classify all mammals with the exception of big game, furbearers, and sensitive, threatened and endangered species as unprotected. This unprotected group customarily includes most of the species in the orders Carnivora, Chiroptera, Insectivora, and Rodentia. "Unprotected" generally means there is no regulated season of take for the animal and in some states an individual does not need a 35 hunting license to kill unprotected animals. Most bats are unprotected in Montana, Nevada, New Mexico, and Utah. C. townsendii is still an unprotected mammal in states (Nevada and New Mexico) where statute regulation changes are lagging behind federal listing changes. NATURAL THREATS Behavioral Ecology The roosting behavior of C. townsendii makes this species highly vulnerable to disturbance. The animals typically roost in highly visible clusters on open surfaces, rarely seeking shelter in crevices as many other bat species do (Dalquest 1947, Barbour and Davis 1969, Kunz and Martin 1982). During the summer months, if undisturbed, a maternity cluster will generally roost in the twilight zone, close to the entrance of a cave or mine. Likewise in the winter, animals are frequently found in well-ventilated areas close to a roost entrance (K. Navo pers. comm., Humphrey and Kunz 1976). Roost sites are usually on ceilings or walls, often at heights below 3 m (Pierson and Rainey 1994, Perkins 1995). C. townsendii is considered a sedentary species with movements typically less than 30 km (Humphrey and Kunz 1976, Wackenhut 1990). Long-term banding studies by Pearson et al. (1952) have shown that nursery colony groups are stable, with individuals showing great fidelity to both their group and chosen roost sites. In light of the many anthropogenic threats to roost sites, roost fidelity itself can be a threat to the species. C. townsendii appears to arouse frequently from hibernation, move among roost sites in response to changes in microclimatic conditions (Keller unpubl. obs., Humphrey and Kunz 1976, Kunz and Martin 1982, Bosworth 1995), and may also shift among alternate maternity sites (Pearson et al. 1952). Yet, disturbance at roost sites has contributed substantially to population declines (Humphrey and Kunz 1976, Kunz and Martin 1982, Stihler and Hall 1993, Pierson and Rainey 1994). Population Ecology Females give birth to one young per year (Pearson et al. 1952). Mortality is high among juveniles. The number of yearling females returning to their natal roost after their first winter averages 38% to 54%. They have about a 80% survival rate in succeeding years (Pearson et al. 1952). Undisturbed C. townsendii populations tend to remain stable (Pierson et al. 1952). The average age of animcds in a population is five years (Pearson et al. 1952), although Perkins (1995) has a band recovery of an individual >21 years old. Low reproductive potential, high longevity and high roost fidelity make C. townsendii populations highly sensitive to roost threats. Baker and Patton (1967) have noted that the genetics of this species is very conservative. It is unclear what the effect of sedentary behavior has on gene flow and diversity. 36 Habitat Threats The loss of caves and mines to natural erosion has been suggested as a possible threat to C. townsendii populations. However, these losses appear to happen over the span of decades and or centuries rather than months or years and likely provide adequate time for populations to adjust. Predation The impact of predation on C. townsendii populations is largely unknown, but unlikely to be significant (Pearson et al. 1952). Tolin (1994) reports unpublished observations (Stihler, Hall) of predation on C. r. virginianus by a black rat snake (Elaphe obsoleta) in West Virginia and by a spotted skunk (Spilogale putorius) in Virginia. Pearson et al. (1952) recorded observations of house cats carrying dead C. townsendii individuals in California. Predation by black rats (Rattus rattus) has been documented on a building dwelling maternity colony in coastal California (Fellers unpubl. data). Altenbach (1994) found Bassariscus preyed on this species as they flew through a restricted opening at the Mariscal Mercury Mine in Big Bend National Park, TX. Predation, interspecific competition, and disease do not appear to be significant factors in the maintenance of C. townsendii populations. PREPARERS: J. Scott Altenbach, Ph.D. Pete Bradley Cindy Bums David Center Barry Keller, Ph.D. Brad Lengas Bob Luce Kirk Navo J. Mark Perkins Paula Perletti Elizabeth D. Pierson, Ph.D., co-team leader Sheri Smith Martha Wackenhut, co-team leader Leslie Welch TECHNICAL COMMITTEE REPRESENTATIVES Chuck Harris, PhD. Lyle Lewis 37 LITERATURE CITED Altenbach, S. 1994. Evaluation of bat habitat and occupancy of the Mariscal Mercury Mine Complex and Rio Grande Village Adit, Big Bend Nation^ Park, Texas. Big Bend National Park 1993 Research Newsletter, p. 80. Bain, J. R. 1988. 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Effects of an operational application of 43 Dimilin on non-target insects. The Canadian Entomologist 125:173-179. , , C. Zivkovich and R.C. Whitmore. 1993. Evaluation of Bacillus thuringiensis and defoliation effects on native Lepidoptera. Appalachian Integrated Pest Management, U.S.D.A. Forest Service. AIPM Technology Transfer. 12 p. Scheffer, T.H. 1930. Bat matters. Murrelet 11:11-13. Schmidly, D.J. 1991. The bats of Texas. Texas A & M University Press, College Station, TX, 188 pp. , K.T. Wilkins, R.L. Honeycutt, and B.C. Weynand. 1977. The bats of east Texas. Tex. J. Sci. 28:127-143. Senger, C., R. Senger, D. Senger, and S. Senger. 1972. Notes on the bat Plecotus townsendii in western Washington. Murrelet 53(1): 10-11 Shoemaker, L.G., and M.J. Lacki. 1993. [ABS]. Selection of lepidopteran prey by Plecotus townsendii virginianus in the Daniel Boone National Forest of Kentucky. Bat Research News 34:128. Soulages, R. 1966. A preliminary survey of eastern Nevada bat caves. Great Basin Grotto. Nat. Speleo. Soc. Stager, K. 1939. Status of Myotis velifer in California, with notes on its life history. J. Mamm. 20:225-228. Stebbings, R.E. 1966. Bats under stress. Studies in Speleology. 1(4): 168-173. Stihler, C.W., and J. S. Hall. 1993. Endangered bat populations in West Virgina caves gated or fenced to reduce human disturbemce. Bat Research News 34(4): 130. Tigner, J., and W.C. Aney. 1994. Report of Black Hills bat survey. Black Hills National Forest. 16 pp. Tipton, V.M. 1983. [ABS]. Activity patterns of a maternity colony of Plecotus townsendii virginianus. Bat Research News 24:56-57. . 1984. Evidence of movement of a maternity colony of Plecotus townsendii virginianus throughout the summer. Va. J. Sci. 35:90. Tolin, W.A. 1994. Virginia big-eared bat {Plecotus townsendii virginianus) recovery plan. United States Fish and Wildlife Service Region 5, Hadley, Massachusetts, USA. 44 Tumlison, R., and M. Douglas. 1992. Parsimony analysis and phylogeny of the plecotine bats (Chiroptera: Vespertilionidae). J. Mammal. 73(2): 276-285. Turner, R.W. and J.K. Jones Jr. 1968. Additional notes on bats from western South Dakota. Southwestern Naturalist 13:444-458. Tuttle, M.D. 1979. Status, cause of decline, and management of endangered gray bats. J. Wildl. Manage. 43(1): 1-17. . 1991. How North American bats survive the winter. Bats 9:7-12. Twente, J.W. 1955. Some aspects of the habitat selection and other behavior of cavern-dwelling bats. Ecology 36:706-732. UDWR Utah Division of Wildlife Resources: Department of Natural Resources. 1980. Bats of Utah. Publication No. 80-15. Wackenhut, M.C. 1990. Bat species over-wintering in lava-tube caves in Lincoln, Gooding, Blaine, Bingham, and Butte Counties, Idaho. Idaho State Univ. Whitaker, J.O., Jr., C. Maser, and S.P. Cross. 1981. Food habits of eastern Oregon bats, based on stomach and scat analyses. Northwest Sci. 55:281-292. , , and L.E. Keller. 1977. Food habits of bats of western Oregon. Northwest Sci, 51:46-55. Whitlow, W.B., and E.R. Hall. 1933. Mammals of the Pocatello Region of southeastern Idaho. University of California Publications in Zool. 40:235-276. Williams, D. F., J. D. Druecker, and H. L. Black. 1970. The karyotype of Euderma maculatum and comments on the evolution of the plecotine bats. J. Mammal. 51:602-606. Wilson, D.E., and D.M. Reeder. 1993. Mammal species of the world, a taxonomic and geographic reference. Smithsonian Press, Washington DC, 1206 pp. 45 CONSERVATION STRATEGY for Townsend’s big-eared bat (Corynorhinus townsendii townsendii and Corynorhinus townsendii pallescens) A. INTRODUCTION C. townsendii is distributed over a broad geographic range in the western United States. Local populations, apparently abundant historicEdly, appear to have declined dramatically. Thorough analysis of past and current distribution of this species is necessary to maintain existing populations in critical areas and to re-establish populations and habitat in areas where the populations are extirpated or diminished. B. GOAL The goal of the C. townsendii Conservation Strategy is: Identify, protect and restore important habitats and viable C. townsendii populations throughout the species range in Idaho and the rest of the western United States. C. STANDARDS The following standards will be followed. Management of Abandoned Mines M - 1. All abandoned mines on public land and public funded closures on private lands must receive proper evaluation as bat habitat prior to closure (Appendix A). M - 2. Roost sites must receive protection consistent with the goal of this conservation strategy. Where gates are used to protect roost sites, they will be designed according to guidelines in Appendix B. M - 3. Agencies will work cooperatively with private landowners of abandoned mines to conserve C. townsendii populations. Management of Caves 46 C - 1 . State and federal land management agencies and local cave groups (grottos) will work cooperatively to identify caves that either currently support, or have historically supported, hibernating bat populations, maternity roosts, and/or other significant bat roosts. The Federal Cave Resources Protection Act of 1988 will be used for guidance in management decisions. C - 2. Implement visitor use restrictions seasonally to protect C. townsendii populations during critical time periods. Close caves used for hibemacula to recreational visitor use from September 15 - May 15, and close nursery caves from April 1 - October 1. The critical time periods of hibernation and maternity activity may vary regionally and will be determined by a qualified biologist. This may allow some site specific flexibility in seasonal closures. a. Use a mix of strategies to protect bat populations depending on the particular cave. This mix of strategies includes gating (Appendix B), public education/outreach, law enforcement, area/trail/road closures, visitor use management. Visitor use strategies will be implemented in coordination with cave user groups where appropriate. C - 3. Agencies will work cooperatively with private landowners of caves to conserve C. townsendii populations. C - 4. The location of caves used by C. townsendii will only be available to the administering agency and the state Conservation Data Center (CDC) or Natural Heritage Program. Use the Federal Cave Resources Protection Act to exempt the release of cave locations from the Freedom of Information Act. C - 5. Agencies will officially request that USGS omit cave locations other than commercial caves from revised 7.5’ topographic maps. Agencies will remove cave locations from maps, brochures, and informational flyers distributed to the public. C - 6. Interact with local caving clubs to encourage confidentiality of caves used by C. townsendii, and support of agency management goals. C - 7. Agencies will develop interpretive brochures, slide and video programs about caves deemed appropriate for general public use. Public inquiries about caving will be directed to local caving organizations for training and guidance. C - 8. Designate caves important for the conservation of C. townsendii as Areas of Critical Environmental Concern (ACEC) and/or Research Natural Areas (RNA) on BLM and USFS managed lands. The Federal Cave Resources Act of 1988 will be used for guidance in management decisions. Renewed Mining at Historic Mine Sites R - 1 . All historic mine workings must be evaluated as bat habitat according to the protocol 47 (Appendix A). R - 2. If bat use occurs, conduct surveys of adjacent vegetation and water sources to determine significance to local bat populations. R - 3. Protect existing bat roosts and associated habitats. R - 4. When roost, water source or forage area sites are to be eliminated or modified, identify and protect suitable replacement habitat in the immediate area that will provide for all life stages of displaced bats. Toxic Material Impoundments T - 1. Eliminate threats to C. townsendii resulting from chemical impoundment (i.e., cynide ponds and oil reserve pits). T - 2. Eliminate threats to C. townsendii resulting from cyanide ponding on heap leach piles. T - 3. Provide C. townsendii clean water alternatives adjacent to areas where toxic fluids are being impounded. The standards for pesticide spraying, vegetation conversion, and timber harvest provide interim guidance to managers. They are based on current information and may be refined as new information supports changes to these standards consistant with the conservation of this species. Pesticide Spraying P - 1. List all C. townsendii roosts within potential spray blocks. P - 2. Survey potential spray blocks for additional C. townsendii roosts. P - 3. Intensify target insect sampling to decrease spray block size. P - 4. Implement management guidelines for protection of riparian and wetland habitats. In determining buffer zones (no spray) considerations should be given to application method and potential for spray drift. P - 5. Utilize 2 mile radius buffer zone around all C. townsendii roost sites. P - 6. Within a 10 mile radius of known roost sites strip spray one-quarter mile strips. 48 The following additional standards will be implemented: Rangeland: a. Utilize species specific control measures when available (e.g. Nosema, specific biological controls) Forest: a. Use silviculture strategies where applicable to reduce the amount of susceptible hosts and to reduce the need to practice direct suppression/spraying. b. Utilize species specific control measures as opposed to non-specific measures where applicable: i. Gypsy moth: pheromone confusants, Gypcheck (not commercially available yet), mass trapping, sterile male release, parasite/predator release. ii. Douglas-fir tussock moth: TM biocontrol, pheromone confusants. In general, these have been shown to be effective only when defoliator populations are very low. Vegetative Conversions V - 1. Maintain or improve riparian and wetland habitats near C. townsendii roosts (10 mile radius) to achieve healthy and diverse structure. V - 2. No prescribed burning or vegetative alteration in shrub-steppe or pinyon/juniper habitats will be conducted within a 1.5 mile radius of C. townsendii roost sites. Prescribed burning in forested habitat will be conducted in alternate years within the .5 mile radius of C. townsendii roost sites. Timber Harvest H - 1. List and identify C. townsendii roost sites within timber sale areas. H - 2. Survey timber sale areas for additional roosts. H - 3. Seasonal harvest activities and road building restrictions will be necessary to avoid disturbance to maternity roosts (April 1- October 15) and hibemacula (September 15 - May 15). The critical time periods of hibernation and maternity activity may vary regionally and will be determined by a qualified biologist. This may allow some site specific flexibility in the above dates. When bats are present year round, a quarter mile radius buffer zone is necessary. 49 H - 4. A buffer zone with a minimum 500 ft. horizontal radius will be maintained around all roost entrances. Inventory. Monitoring, and Research Protocols I - 1. Establish permitting requirements for all investigators working with bats. Permits will require training from an experienced bat biologist. Training will include awareness of health and safety precautions for handling bats and working in bat habitats. 1-2. Guidelines outlined in Journal of Mammalogy (Vol 73(3):707-710, 1992) (Appendix C) and subsequent revisions will be followed, with the more specific restrictions outlined below. 1-3. Due to the great sensitivity of this species to disturbance at roost sites, maternity roosts should never be entered unless absolutely necessary, and under no conditions should animals ever be removed from or disturbed in a nursery cluster. If a maternity roost is entered it should be done by no more than two people, using night vision equipment or lights covered by red filters, making as little noise as possible. Investigators should never pass directly under a maternity cluster. Ideally monitoring of maternity sites would be done by evening exit counts. Any netting or trapping of animals at maternity sites should occur outside the roost and away from the roost entrance. 1-4. Monitoring of hibernating sites should be kept to a minimum. These sites should not be entered more than once every two years unless absolutely necessary. Surveys of hibernating sites should be conducted with the utmost caution (i.e., as quickly and quietly as possible, by no more than two people at once). Hibernating animals should not be handled unless absolutely necessary. 1-5. Due to a history of band-induced injuries, the banding of C. townsendii is discouraged. 1-6. Scientific collection and banding will be limited through the permitting process. 1-7. Locations of C. townsendii roost sites will be treated as sensitive information, with access restricted accordingly. 1-8. Establish an interagency, interstate working group to continue to consolidate inventory and monitoring information, provide educational materials to biologists, coordinate research, and act as an advisory group to provide assistance or advice to deal with population or habitat problems for C. townsendii. At a minimum the preparers of this document will form the initial working group. 50 D. INVENTORY AND MONITORING An active inventory and monitoring program is needed to further identify C. townsendii habitat and assure the maintenance of viable populations across the bats’ range. Regular population and habitat assessment provide valuable information on causal mechanisms and effects of various disturbances. Inventory and monitoring data should be used to evaluate the success of this conservation strategy and to contribute to an adaptive management program. Inventory Abandoned mine and cave inventory for C. townsendii will be conducted according to the protocol outlined in Appendix A and C. Monitoring It is particularly important to monitor populations in a managed landscape to assess various impacts of land management activities and to evaluate the success of this conservation strategy. Monitoring for C. townsendii presence will include: 1) annual nonintrusive monitoring of selected sites across the species’ range, following monitoring guidelines outlined above, 2) 10-year extensive monitoring at all sites, 3) monitoring of sites potentially affected by management actions one year before and annually for three years after implementation of management activities, and 4) monitoring of selected bat gates for effectiveness and acceptance. State Status Encourage individual states to elevate state status of C. townsendii where appropriate. Ecological Research Although much has been learned about C. townsendii in the last decade, a number of management questions remain to be answered. Issues critical to effective management of this species are: 1 . Examine range of roost sites used by C. townsendii throughout its range, especially in areas where roosts for known populations have yet to be found. 2. Collect data on structural microclimatic roost parameters (e.g., roost location, temperature and humidity) with the goal of developing predictive screening criteria for roost site evaluation. 3. Foraging ecology a. Through radiotelemetry, define habitat used by C. townsendii for foraging. b. Through radiotelemetry, evaluate responses to land management practices, such as timber harvest and grazing. c. Develop guidelines to mitigate for any impacts resulting from these activities. 51 d. Obtain baseline data on the seasonal and temporal activity patterns of insects in bat occupied areas. Baseline insect population data should be collected for several years. 4. Effects of toxic materials a. populations. b. Determine direct and indirect effects of pesticide spraying on C. townsendii Determine the effects of contaminants on populations. 52 1 -■I I i APPENDIX A Evaluation of Bat Use in Abandoned Mines Principal Author J. Scott Altenbach University of New Mexico The need to secure abandoned mines for human safety seems in conflict with the fact that 64 percent of the bat species of the continental United States are known to roost in mines (Pierson, et al. 1991, ASM 1992). In addition, populations of many species have experienced serious population declines in recent years (Graham 1966, Mohr 1972, Tuttle 1977, Perkins 1985, Clawson 1987, Pierson 1988). It is clear that relatively little is known about basic requirements of many species of bats and that closure of mine roosts could have serious, negative consequences to the species that use them. There is evidence that recreational activities and destruction of habitat have played a major role in this decline and that examples of human-caused mortality at traditional roosts are common (Mohr 1972, Tuttle 1977, Altenbach, Unpubl. obs.). It has become clear that abandoned mines provide a refugium. Because roost requirements differ widely during different times of the year, the timing of surveys is critical and will be discussed in the context of different types of mine survey protocols. Described herein are procedures that have been used in the evaluation of abandoned mines for bat use and occupancy. While this protocol was written in terms of mine survey and protection, the survey techniques and closure considerations also apply to natural caves. Safety and caving ethics also play a role in cave surveys. Anyone conducting cave surveys for bats should consult with or join a local grotto to stay current with cave safety training and equipment and caving ethics. Mines can be used by different species of bats with widely differing requirements for temperature, relative humidity and air flow. The use can be for hibernation, intermediate roosting between warm and cold season, migratory stopover, warm season maternity roosting, bachelor colonies, night roosts and possibly for developmental diapause during the warm season. Mines may provide last-resort habitat for bats displaced from traditional roosts used for any or all of the above by destruction or disturbance. Bat biologists have much to learn about roost preference criteria, but numerous observations suggest temperature is an important factor affecting distribution within roosts (Tuttle and Stevenson 1978). The simplicity of a mine may provide seasonal temperature fluctuations 53 just as complexity may provide extreme, regional, internal temperature variation. It is important to consider that nearly any mine can be a habitat for bats at different times of the year, and until you survey, you can not conclude if the mine is used by bats. MINE INVENTORY AND SURVEY PROTOCOL Inventory and Initial Survey The initial survey of an inactive mine or group of inactive mines scheduled for closure involves location and description of ALL mine openings (features) including: dimensions, elevations relative to other openings, airflow direction and airflow temperature, obstacles in opening (rocks, vegetation, limbs, trash, portal or headframe timbers), potential hazards, depth of the mine feature (vertical or horizontal) as can be observed from outside, presence of drifts as can observed from outside, observations of any wildlife or wildlife sign (e.g., excrement, carcasses, etc.), collection, if possible, of potential bat guano from immediately inside the opening if safe to do so. In some cases mine maps are available and can give an idea of the size and internal configuration as well as the interconnection of multiple portals and openings. For many older mines, however, no maps may exist. The size of the mine dump may indicate a proportionally high volume of internal workings, but the inverse may not be true. Figure 1 illustrates typical mine features and associated terminology. In an initial survey, a mine can often be eliminated as a possibility for bat habitat. If the rib (side), back (ceiling) and sill (floor) of shallow adits and rib (side) of shallow shafts can be observed clearly enough to determine that no lateral workings are present and no sign of use by bats is seen, it is safe to assume the mine has low potential as bat habitat. If a shaft is flooded above any lateral workings or if an adit is flooded to within a foot of the back (ceiling), even periodically, it can be considered to have low potential as a maternity roost or hibemacula, but it could be important as a night roost or drinking water source. Even though persons doing external surveys (either initial surveys or external bat surveys) are not required to go underground, they should realize that hazards exist even on the surface around abandoned mines and should have proper training on the hazards and how to avoid or minimize them. Navo (1994) discusses possible levels of training for personnel, as do Perkins and Schommer (1991). Internal Survey The subsequent discussion of internal surveys of abandoned or inactive mine workings is provided to illustrate the approach used in internal surveys in mines and to illustrate the extent to which such mines are used by bats. This is not a recommended protocol for others to conduct such surveys, nor is it intended as a complete description. Abandoned or inactive underground mines are not safe to enter, and there is no way they can be 54 Bats AND Mines 11 Figure 1. Typical mine features and terminology. In this example, the highest and lowest temperature air would be trapped at locations A and B respectively. Mining Terminology Adit — A horizontal mine passage driven from the surface for the working or de-watering of a mine. Bald Raise — A raise with no drifts or horizontal workings. Drift — A horizontal underground mine passage following a vein. Orebody — A mineral deposit that is being mined for its metals. Outcrop — That part of a stratum or vein that appears on the earth's surface. Portal — A horizontal mine entrance. Raise — A vertical or inclined opening driven up- ward from one mine level to connect with the level above, or used to explore the ground above a level. Shaft — A vertical mine opening from the surface into a mine. Stope — An underground cavity made by the removal o’ .ire. An overhand stope is made by working upward from a mine level, and an under- hand stope is made by working downward beneath a mine level. Sump — A hole dug at the bottom of a mine shaft to collect water. Vein — A fault in the ground that contains valuable minerals. Winze — A vertical or inclined opening sunk down- ward from inside a mine for the purpose of connec- tion with a lower level, or for exploring the ground beneath a lower level. made safe. Persons entering them must understand and accept the associated risks. Anyone entering abandoned underground workings must have appropriate training and experience with the associated hazards and with the ways to minimize them. Caving experience does not qualify someone to enter an underground mine. Safety Equipment Used The MINIMUM safety equipment needed for underground work includes: Approved hard hat with chin strap, three sources of MSHA-approved light, gas detector (a combination O2, CO, combustible Gas), O2 detector with remote sensor head, oxygen generating self-rescuer. Additional equipment such as a respirator with filters for particulates and ammonia is useful in some situations, especially where populations of deer mice and wood rats, potentially infected with Hantavirus (Hjelle et al. 1994), may be present. Should extensive dust particles be encountered, approved hepa filter half-face masks may be used. If any vertical climbing is required, the appropriate, specialized equipment and training (as well as practice) in its use is obviously vital. Vertical climbing in abandoned mines, especially in shafts, is an order of magnitude more dangerous than typical vertical mountaineering practice and is warranted under only rare circumstances. If additional survey is warranted, an internal survey, conducted by an experienced bat biologist on a contract basis, has proved to be the quickest and least labor/time intensive of the survey options. The leader of any internal survey needs experience with identification of bats and general bat biology as well as with mines, mine safety and hazards peculiar to abandoned or inactive underground workings. This person must make a decision that an internal survey is possible within the limits of safety, must make a decision to abort an internal survey if warranted, and must decide whether an external survey is the only option. When it is determined that an internal survey is possible the following approach is one that has been used by the contractor in the cooperative program between the New Mexico Abandoned Mine Lands Bureau and the University of New Mexico. Aspects of this protocol are discussed in greater detail in the following section. Key to Mine Survey and Management Decision Go To Key Item A Complete Internal Evaluation Possible B A’ Complete Internal Evaluation Not Possible G B Cold-Season Survey No Guano, Sign or Residents F Guano or Other Sign C Residents C,E Internal Conditions (water) May Obscure Sign C 56 C Warm-Season Survey No Residents-Night Roost, Migratory Use D Residents E D Fall or Spring Survey, Dropping Boards No Residents, No Additional Sign (Roost Abandoned) E,F Residents, Additional Sign E E Decision to Bat Gate Involving Following Questions Is a Threatened or Endangered Species Involved? Is Use Significant? Are Alternative Features, Used in the Same Way, Nearby ? How Feasible is Bat-compatible Gating? Will Preservation of an Abandoned Roost Provide Habitat or Mitigate Habitat Destruction Elsewhere ? F Closure By Any Means (If possible after a final inspection, mist netting and tarping or smoke bombing before closure) G External Survey DISCUSSION OF INTERNAL EVALUATION PROTOCOL Cold-Season Survey (Key Item B) During the initial cold-season check, note is made of the layout of the mine and of the possibility that parts of the mine cannot be explored. Corynorhinus townsendii has been found on the rib of deep bald shafts and in deep drifts which act as cold air traps. Such features should not be discounted. If it is determined that parts of a mine cannot be explored, external evaluation of the mine is required. If internal evaluation is possible, careful checking of even tiny cracks or holes in the back and rib is necessary, because some species of bats hibernate in such openings. C. townsendii, however, rarely occupies cracks and commonly is visible on the ribs and back of adits and drifts. Measurements of temperature, relative humidity and airflow in different parts of the mine are made at this time and add to our understanding of the roost requirements for bats and our understanding of how internal mine environment correlates with external temperatures and conditions. If bats are encountered in a cold season survey, they may be identified by inspection under red light. Mine and flashlight beams should not be aimed directly on hibernating bats for any length of time, and attempt at identification must be limited to the minimum time 57 possible. Getting exact counts of clustered or scattered bats does not warrant the disturbance involved. A quick estimate of numbers or of the size of a cluster is adequate and disturbance should be kept at a minimum. Warm-Season Survey (Key Item C) Internal surveys during warm season are conducted with extreme care. Many species of bats are intolerant of disturbance at the roost site, especially during the time they are having and caring for pups. Disturbance can easily cause relocation of a colony and, worse, mortality of pups (Mohr 1972, Humphrey and Kunz 1976). A mine is approached, entered and explored quietly during a warm season check. Serious disturbance of alert bats to make an identification is not warranted. An experienced bat biologist can make an identification of some species with a quick glance. If bats cannot be identified without disturbing them external evaluation involving netting, trapping or bat detectors is required. If no bats are found in residence, the bat sign (typically guano pile or scattered guano) can be carefully searched for the discarded invertebrate appendages and wings that indicate night roosting. If night roosting is suspected, the mine is again entered at night to observe the species and numbers involved or is mist netted at night. Bats are seldom encountered in mines used as migratory stopover roosts, and identification of the species typically involves a careful search for carcasses which can then be identified. Repeated visits to the mine in the time period when use is thought to occur makes encountering and identification of the residents more likely. Fall-Spring Surveys (Key Item D) Fall surveys might document species flocking in preparation for hibernation and both spring and fall surveys might document bats using a mine feature as a migratory stopover. Maternity use obviously is best detected from mid-May to August, a period during which bachelor colonies may also be detected. Decision to Bat Gate (Key Item E) If C. townsendii is using a mine, the decision to use some type of bat-compatible closure is clear but must involve consultation with appropriate state and/or federal authorities. The question of how to define "significant use" is difficult. A single, hibernating C. townsendii is probably not sufficient cause to close a mine with a bat-compatible closure at great expense. Ten hibernating C. townsendii probably is, but the decision must be weighed against the complexity, feasibility, cost and reliability of such a closure. It must also be weighed by the presence or absence of a comparable mine feature, used in the same way. 58 being nearby. As an example, a mine in Grant County, New Mexico, was used as a hibernaculum by over 25 C. townsendii. The mine was an open stope that averaged about 20 feet in width, was over 100 yards long, and was over 100 feet deep in places. The cost of a bat-compatible closure was astronomical, but within a quarter mile was another mine, used by this species as both a hibernaculum and maternity roost, that was much more suitable for a bat-compatible closure. The first feature was blasted shut during the interval between maternity and hibernation time (after clearing with smoke bombs the night before blasting), and the second was fitted with bat-compatible gating on three of its entrances and with cable netting on the others to maintain airflow. A maternity colony of any species is significant and is cause for installation of bat-compatible closure, but such a closure must be weighed against costs, feasibility, and availability of comparable, more easily gated features nearby. Bat Compatible closure and Follow-up (Key Item F) If the use is significant or if alternative, comparable sites do not exist nearby and closure is feasible, the mine feature is closed with bat-compatible gating, the bat-compatible closures are designed for each mine feature by AML engineers and are typical of those described elsewhere. Secondary openings not used by bats are closed by any means that will permit airflow and deny human entry. If bat use is likely through a secondary opening which is closed by cable netting, angle iron-reinforced openings are provided in the net. After closing in this manner, the feature is checked periodically to assess subsequent use. At the present time, remote monitoring and data storage systems are being used to collect data on all aspects of mines with bat-compatible closures. Timing of Mine Closure The selection of appropriate "time windows" for non-bat-compatible closure must minimize the chances that unknown residents will be trapped inside. Installation of bat-compatible closure must likewise be timed to minimize disturbance of residents. These time windows will vary with the type of use, the species present, and the region of the country. Closure activities need to be coordinated with the help of local bat biologists. External Evaluation Protocol (Key Item G) Anyone interested in the protocol for external surveys is encouraged to consult Navo (1994), who describes a successful program in Colorado that uses volunteer help in conducting external mine surveys. If a mine or mine complex is deemed a possible bat habitat but cannot be entered because of hazardous conditions or because trained or experienced persons are not available for an internal survey, a series of external surveys is in order. The timing 59 of the surveys is critical and depends upon the seasonal changes in bat activity typical of the region in question. Publications on the biology of species that might be in a particular area, as well as consultation with local bat biologists, provide a good starting point for planning and timing of external surveys. Fall surveys (mid-August through mid-October) might encounter species flocking in preparation for hibernation and both spring (March through mid-May) and fall surveys might encounter bats using a mine feature as a migratory stopover. Maternity use obviously is best detected from June through late- July. Bachelor colonies could also be detected at this time. Surveys are conducted by observers stationed off to the sides of the mine portal on nights without rain or strong wind. Setup is kept quiet and is complete at least 30 minutes before sunset. Observers are stationed at least 15 feet from the sides of a portal, not directly in front of it. After it is too dark to see bats silhouetted against an evening sky, red lights are shined across the portal, not into it. Night vision devices, although very costly, are superb for observation of mine entrances on dark nights and work well with an infrared light source. Observations are conducted from sunset to at least two hours after sunset, and as much information as possible about numbers counted going in or out of the mine is recorded. All entrances in a particular area are checked, with as many as possible checked on the same night. Bats often use only one entrance of a mine that may have several. Disturbance at one entrance may cause bats to use an alternate portal. An external survey will usually detect bats that are using a mine the night the survey is done. An external survey cannot detect bats that just left or that don’t go out that night. Bat detectors have been used successfully in external evaluation. If possible, broad band detectors are preferable, but narrow band detectors are suitable if they are scanned to maximize the chances of detecting bats. Typically, one starts with a setting of 35 KHz and scans over the range of 30 to 40 KHz. Knowledge of the echolocation characteristics of local bats is important to identify the species of bat detected. External Capmre Survey Capture of some individuals for positive identification is warranted if unidentified bats are encountered during an internal survey during warm season, if a warm-season external evaluation substantiates the presence of bats, or if a night roost is discovered. Persons conducting capture surveys must be thoroughly capable of field identification, be rabies immunized, and have necessary state and/or federal collecting permits. Set-up of mist nets or harp traps is completed at least 30 minutes before sunset and is done as quietly as possible. Nets or traps (with someone in attendance at all times) are left up at least two hours after sunset, or later if there is a possibility that the mine is used as a night roost. After enough bats have been caught for identification and released, the nets are taken down to minimize disturbance. Data on species, sex, and reproductive status is usually recorded. 60 Alternative External Survey Possibilities The possibilities for external surveys (personnel not going underground) are limited only by the imagination, the technological capabilities of the personnel and available funding. The following are approaches that have been tried as prototypes by persons doing bat surveys, and are suggested as possibilities worth modification and experimentation. Robotic Video Camera: A video camera, enclosed in protective case and equipped with a light, has great potential for evaluating shafts. Pete Bradley (pers. comm.) has tried lowering a camera on a single tether and has produced a scan of the shaft rib as the camera spins during its descent. David Dalton and Marion Vittetoe (pers. comm.) have used the same technique but have used a four-point suspension of the camera to retain positive control of camera point. These techniques could be improved by a video link to the surface to allow personnel to see what the camera sees without having to wait for a playback after the camera is pulled to the surface. A control hookup to the camera could allow focus and increase illumination to see into horizontal workings. At a minimum, these techniques offer the possibility to safely evaluate shafts for potential habitat. Bat detector coupled to data logger; A bat detector coupled to a data logger allows a nightly survey of a mine portal over an extended period (e.g. each night over a month) without the time expenditure of a survey team. The technique has a good probability of detecting bats entering a mine as a hibernation site. CONCLUSIONS It appears that, in a mine of any size, there is little to indicate if bats might use it. Significant numbers of bats have been found in deep, single-portal shafts, on the rib of bald shafts, and deep in horizontal features which show absolutely no evidence of bat use in their shallow passages. Another aspect of the unpredictability involves the near impossibility of determining the internal complexity, the number of interconnected openings, and the internal volume of a large mine or mine complex based upon an external evaluation. This unpredictability has been complicated by the observation that many mines which appear to have no warm- or cold-season use, function as short-duration pre- or post-hibernation interim roosts. Mines which are not used for hibernation and have no sign of warm-season use have been occupied by C. townsendii when checked in mid-March and September. 61 X LITERATURE CITED ASM. 1992. Guidelines for the protection of bat roosts. J. Mammal. 73:707-710. Clawson, R. L. 1987. Indiana bats: Down for the count. Bats 5:3-5. Graham, R. E. 1966. Observations on the roosting habitats of the big-eared bat, Plecotus townsendii, in California limestone caves. Cave Notes 8:17-22. Hjelle, B., S. Jenison, G. Mertz, F. Koster, and K. Foucar. 1994. Emergence of hantaviral disease in the southwestern United States. West J. Med. 161:467-473. Humphrey, S. R. and T. H. Kunz. 1976. Ecology of a Pleistocene relict, the western big-eared bat, {Plecotus townsendii) in the southern great plains. J. Mammal. 57:470-494. Mohr, C. E. 1972. The status of threatened species of cave-dwelling bats. NSS Bulletin 34:33- 47. Navo, K. W. 1994. Guidelines for the survey of caves and abandoned mines for bats in Colorado. Colorado Division of Wildlife. Perkins, M. 1985. The plight of Bats 2:1-2. Perkins, M. and T. Schommer. 1991. Survey protocol and the interim species conservation strategy for Plecotus townsendii in the Blue Mts. of Oregon. Report for the Wallowa- Whitman National Forest, Baker City, OR 97814. Pierson, E. D. 1988. The status of Townsend’s big-eared bat (Plecotu townsendii) in California. Draft Report. Wildlife Management Division, California Department of Fish and Game. 34 pp. , W. E. Rainey, and D. M. Koontz. 1991. Bats and mines: experimental mitigation for Townsend’s big-eared bat at the McLaughlin Mine in California. Pp. 31-42 in Proc V: wildlife. Thome Ecological Institute. Boulder, CO. Tuttle, M. D. 1977. Gating as a means of protecting cave dwelling bats. Pp. 77-82 in T. Aley and D. Rhodes, eds. Proc. Nat. Cave Management Symp., 1976, Mountain View, AZ. and D. E. Stevenson. 1978. Variation in the cave environment and its biological implications. Pp. 108-121 in R. Zuber et al. eds. Proc. Nat. Cave Management Symp., Big Sky, MT. 62 •'S'-'. K* ■ v‘ V iliT iliOI'*! '- i - lOI JlW S« :l' r . jtJiKXJ jSliJ lO' .S " t^ri' V' no H ^ AH/i SS 3t0ioiHftO ai .. fi/fijiifiK V '■'^ ■ '4^1 HA.- 'VX V: ; . r.i!-:.OA . Bf fiiil ' %j r^i-A :i 'JC^ .b't' w ^ ^b£-ioio ' ;^ •■- ; (,. ' W m- ..j.fkpJfS/' ai , .tj -i M- '-i f??r?ri ^ u-r::.tUO, ;^‘ - ■ '- ■ ■■ ■<■ ' ' ' - ■ — A r j-i ,2j.‘i . ..'■%- t.^^'* -■'-'- •?r/Tr x/:i;4^:.:ixm &4: , '4’t^4'= "' M- .. J .X'-*"/ . ; ,v<3fe rrOlT .'Jtiibli'^ r fu ;’tf^ ' o ■ ■-■' ^ ■; --t" x' ■ M ■ ' " li>Ai*Ofok1 ?Ji I'JilR I5i •auil.iMh^V .^sAf n -U L'^ir - .ninv'r" 1^4::..S K &• .’■■^f'-80l ^’’'s' ■:.W ' 'i-'V ' ■Br/ -VX- ;(•>■’■''>■•'■ . " ;' (/) 0) W *- t/3 (D XJ ro 0) TJ c (0 .CD o 0) Q. CA c o c o < C JS •5 3 CD J2 S o 0) u w ^ o 5 C/) ™ o O ~ c ™ ro ^ 0 t •3 O CD 0) 1 “ 0) o jz •.;= — o >< (fl w c 0) o ■c o 3 — o c 0 0) -g S ■|£ o.< 0>O “■ o i2 1 § f- o CD X C < QJ C rv bO Qh < Q TO 3 c C 0 C Q. CO a. T3 < 0) V> 0 0 ■> 0> w (/) 0) ■O <0 0 0 ■o c c (0 rc c g o 0 o. To w o c o o w c w < g c ro g 3 To (/) c o 0) o (/> c o o «*— O o 0) > (0 O (/) c g c (0 g To o c 'w o 0) 0 E o. (/> < c (U o sz o 3 o >. T/3 (0 c 0 o •c o 3 . ■ o c o 0 ■D w 0 -a 3 o ■> o Q.< o O w o TO < (/) c 0 TO £ X • ^4 C < QJ C 8 < Q o O 0) > re O c re o 'C (U E < © 3 >% jQ T3 0) iC re 0) o Q. >. iO ^ *0 "O re ID 0. O HORIZONTAL BAR SPACING TYPICAL DETAIL 'A*rC 30 X 15 T3 Z3 C C (1) C Q. ro Q. ■D < a; (/) 0) 0 ■> (/> ' — ' u. CO (1) ■O k— n3 0) (D •a c c CD rc C .2 o CD Q. 16 CO o C o o (/> < c o c ro o 3 16 & CO c o a> o (/) L- c o o O k_ o (1) > CD O CO c .2 c CD O ro o c^ O o; 0) E Q. CO < c CD ,2 o 3 O >< V) CO c CD o tr o 3 o c o •D *> o kS 0) o o TO CO < c 0} TO Q. o (D ro (/> 0> c -C o O X • ^ c < QJ C n . c/5 ^ o < Q q: O z o o Ul u < CL i/> Z o q: O z < \ K) X2 X j o ^5 CO < h“ Ld Q in z < < u V) o o z o O O c o CD u o TO o a> E < © c 3 (/) TO 5 •o 0) cr TO if 0) $ o CL CO c 0) .5^ C7> TO w Q) ^ W 0) TJ ro 0) ■D C ro ro o 0) Q. w c o c o < = c 2 ro w ^ o 0) o 2 ^ o > c ™ o O -2 c ™ ra ^ 0 t c o 0} < w w c CO (U u. CO 0) ■D L- CD Q> d> T3 c C CD rc C o ro o 0) d (0 o c o o (/) in < c o c TO o 3 ro & CO c o 0) o CO w c £ o (J o a> > CD o CO c o c CD O ro o c 'k. o CU 0) E d (0 < c (U o o V4— D o u. >< to CO c 0) o n o 3 o c o 3 ■o w 0) 3 •3 CJ ■> o o Q. < CD O O CD < c/) (D c CD d d CD O ro CO CD 3 -C o O < O) c 3^ s < Q c g 15 o o (/> c o O o > (D o 0> E < >% Xi TD 0^ .2^ o> . and indirect disturbances to the roost and surrounding habitat. Persons entering maternity colonies can cause bats to aban- don young or drop them to the floor from where they are usually not retrieved and subsequently die (Gillette and Kimbrough. 1970; McCracken. 1989). In addition, the handling of pregnant females has been known to cause abortion (Gunier. 1971). Disturbance dunng hibernation may cause bats to arouse prematurely, elevating their body temperatures and utilizing stored en- ergy reserv es which usually cannot be spared. Bat specialists have estimated that each arousal of hibernating bats can rob them of 1 0 to 30 days of stored fat reserves (Thomas et al.. 1990; Tuttle. 1991). Bats may return to a state of torpor after disturbance, but then may not have sufficient energy to sur- vive the rest of the winter. In addition, bat caves are vulnerable to habitat alteration and degradation. Changes in cave micro- climate (e.g.. humidity, temperature and air flow) are imposed through modification of cave entrances. Clearing trees from around cave entrances may result in an overall in- crease in summer temperatures or a de- crease in winter temperatures, both of which may render a cave uninhabitable. The nat- ural air flow in and out of a cave or its humidity may be altered to such an extent that the habitable portions are reduced or eliminated (Hill and Smith. 1984). Distur- bance and destruction of roosts, especially caves, have contributed to the listing of many species and subspecies of bats on the U.S. Fish and Wildlife Service's list of en- dangered and threatened species (Mc- Cracken, 1989; Mohr, 1972). Such desig- nations and the subsequent recover\’ efforts require bat specialists and wildlife managers to monitor remaining populations. Guide- lines presented herein should be considered as minimum precautions when dealing w'ith roosts containing endangered or threatened 707 70S JOURNAL OF MAMMALOGY ^'o/. 7S, No. 3 taxa. These guidelines should also be con- sidered when working with other bat roosts as well, because severe reduction or elimi- nation of populations through careless entry may eventually lead to additional species and subspecies being threatened. In addi- tion. we know very little regarding the actual status of some populations of most bat spe- cies, and many species that are not listed as threatened may warrant listing and need the protection that goes along with it (Mc- Cracken, 1989; Stebbings, 1980). More- over, several species of bats often use the same roost; thus, a roost containing mostly non-endangered species may also harbor endangered ones (Hill and Smith, 1984; McCracken. 1989). This lack of knowledge regarding the status of bat populations em- phasizes the real need for precautions around roosts of all bats (Stebbings, 1980). As an additional precaution, we recommend that any species of cave-dwelling bat be treated as though their populations are in decline; exceptions should be limited only to those cases for which substantial evidence exists to the contrary. Recommended Guidelines 1 . Avoid revealing exact locations of bat roosts. Many bat specialists have already adopted this practice, often after declines in populations, damage to roosts, or both, have taken place soon after a publication re- vealed the roost location. 2. Caves or other structures designated as cntical habitat for endangered or threat- ened species should not be entered except by federal or state management biologists or researchers with valid permits when bats are present. 3. Caves protected by fences or gates should not be entered except by special per- mit holders, regardless of species of bat present. 4. Caves protected by warning signs about bat nursenes or hibernating bats should not be entered dunng the times of year specified on the sign. Entrv- can be permitted at those times of year when bats are not present, so long as the cave is left unaltered and un- polluted. 5. Although species’ tolerances differ, maternity colonies of endangered or threat- ened bats should not be visited, unless there is a special need and a federal permit has been obtained. Maternity colonies of non- endangered or non-threatened bats gener- ally should not be disturbed. It is highly recommended that if maternity colonies must be visited that it be done at night while the adults are away from the roost. 6. For bats whose populations are either known or suspected of being in decline, most field research, including banding, should be discontinued while the bats are hibernating. Even for monitoring purposes, disturbances should be as brief as possible and should occur no more than once per winter, pref- erably in alternate years. In general, winter banding efforts for any bat population should be minimal and clearly warranted because arousing bats to band them can cause ex- cessive mortality. 7. Persons entering bat roosts should re- duce their impact by minimizing noise and the number of participants. Lights should be limited to those powered by batteries or cold chemicals such as cyalume. Persons should avoid passing too closely to roosting bats, and should leave no refuse or other signs that they were there. 8 . Research on federally listed bats should be earned out through stnngent adherence to the terms of federal and. when applicable, state permits. 9. Persons collecting bats need to be aware of federal and state laws governing the collection and transponation of bats, and must be in possession of the appropriate scientific collecting permits before the study IS undertaken. When bats are collected for laboratory research, proper handling and transportation of captured animals should be practiced to minimize injuries and/or deaths, and therefore the actual numbers taken from a roost. 10. In nearly all cases, collecting should be done at, near or outside roost entrances 4ugust 1992 PROTECTION OF BAT ROOSTS rather than inside the roosts. Collecting is usually done with harp nets placed at or near roost entrances or with mist nets placed out- side roost entrances. .A limited amount of collecting can be safely done inside large cavern systems or in some man-made struc- tures. Collectors should avoid captures in excess of numbers needed by estimating the size of colonies before setting up nets. 11. Collections should be minimal, in- cluding only a small fraction of the popu- lation of any given colony, should not be redundant with existing collections, and should be sufficiently infrequent to ensure that healthy colonies are sustained. Col- lecting should only be done as a means of furthering our knowledge and understand- ing of bats and not just because the bats are there. 12. Collecting should be done so as to avoid any damage to the cave or other roost structure. 13. Firearms, open-flame torches, smoke or toxicants (including pesticides) should never be used inside bat roosts. 14. Despite their genetic, ecological and economic importance, bats have an image problem and are not popular with most of the public. Current public attitudes towards bats threaten their survival, especially since the first reaction of most people to their presence in houses or buildings is to elim- inate or remove them as quickly as possible (Hill and Smith, 1984). Because popularity IS a major stimulus for conservation, we recommend that wildlife agencies, spelunk- ing societies, colleges and universities, and nature centers, in conjunction with bat spe- t^ialists if possible, increase their efforts to educate the public about bats. These efforts ^ould include newspaper and magazine ar- ^'cles and talks directed at school children, conservation groups, spelunking clubs and land owner groups. In addition, we rec- onimend continuing education programs dealing with bats be directed at wildlife ntanagers, conservation officers, wildlife Commissioners, animal damage control Agents and veterinarians. Adequate proiec- "OQ tion for bats may be next to impossible without an educated public (Tuttle. 1979). Through such education efforts, the public can be made more receptive to restnctions on human activities in or near bat roosts. 15. .Although many of the guidelines pro- posed herein call for various permits for research, we do not imply that merely hold- ing permits will ensure against detnmental effects of study. The Amencan Society of Mammalogists expects that scientists will maintain high professional standards when conducting research in and around bat roosts. 16. We recognize that special circum- stances may require these or any other guidelines to be violated for the welfare of an endangered or threatened species. De- cisions on such matters will have to be made on an ad hoc basis by bat specialists and recoveiA' team members in conjunction with the appropriate wildlife agencies. We intend these guidelines as general guidelines only, subject to modification under extenuating circumstances or as new information be- comes available. .Acknowledgments We would \ er> much like to thank B. S. Clark. ,M. J. Harvey. T. H. Kunz. J. L. Patton. R. .M. Timm. M. D. Tuttle, B. J. Verts. K. T. Wilkins. D. E. Wilson, and two anonymous reviewers for their helpful suggestions on improving these guidelines. Literature Cited Barbour. R. W'.. and W'. H. Davis. 1969. Bats of •Xmenca. University ofKeniuckv Press. Lexington. 286 pp. Gillette, D. D,. and J. D. Kimbrough. 1970. Chi- ropteran mortality. Pp 262-28.t. in .About bats: a chiropteran biology sxmposium (B. H. Slaughter and D. W. Walton, eds.). Southern Methodist Unixersity Press. Dallas. Te.xas. 339 pp. Gtmer.W . J. 1971. Stress-induced abortion in bats. Bat Research News. 12:4. Hill. J. E.. and J. D Smith. 1984. Bats: a natural historx. Lmiversits of Texas Press. .'Xustin. Texas. 243 pp. MrC'RAC K.EN. G. F. 1989. ( axe conservation: special problems of bats. National Speleological Society Bulletin. 5 1 :47-5 1 . Mohr. C. E. 1972. The status of threatened species 710 JOURNAL OF MAMMALOGY Vol. 73, No. 3 of cave-dwelling bats. National Speleological Society Bulletin, 34:33-47. Stebbings. R. E. 1980. .An outline global strategy for the conservation of bats. Pp. 173-178. in Proceed- ings of the Fifth International Bat Research Confer- ence (D. E. Wilson and A. L. Gardner, eds.). Texas Tech University Press. Lubbock, Texas. 434 pp. Thomas, D. W.. M. Dorais. and J-M. Bergeron. 1990. Winter energy budgets and cost of arousals for hibernating little brown bats. Myolis lualugus. journal of Mammalogy. 7 1 :475-479. Tuttle. M. D. 1979. Status, causes of decline, and management of endangered gray bats. The Journal of Wildlife Management. 43:1-17. . 1991. How North Amenca's bats survive the winter. Bats. 9:7-1 2. Prepared by the Protection of Bat Roost Guidelines subcommittee, Steven R. Sheffield, James H. Shaw, Gary' A. Heidt, and Leroy R. McClenaghan. of the Conservation of Land Mammals Committee. These guidelines were ap- proved by the Board of Directors on 21 June 1987 at their annual meeting in Albuquerque. New Mexico. 1! ■' :.VY ’■■-V- . f-. .A