FISH &WILDLIFE REFERENCE LIBRARY Technical Report #88-5-01 1987
DISTRIBUTION, STATUS, AND HABITAT AFFINITIES OF TOWNSEND'S BIG-EARED BAT (PLATOTUS TO WNSENDIT) IN okPdaN
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Oregon Department of Fish and Wildlife Nongame Wildlife Program DISTRIBUTION, STATUS, AND HABITAT AFFINITIES OF TOWNSEND'S BIG-EARED BAT (PLECOTUS TOWNSENDII) IN OREON
J. Mark Perkins Consulting Wildlife Biologist
Compiled with Connie Levesque Oregon Department of Fish and Wildlife
Oregon Department of Fish and Wildlife Nongame Wildlife Program Technical Report #86-5-01
1987 CONTENTS
P age
FIGURES ...... iii TABLES iv ...... ABSTRACT 1 ...... INTRODUCTION 1 ...... STUDY AREA 2 ...... METHODS 3 ...... 3 Winter Surveys ; ...... Summer Surveys 3 ...... RESULTS 6 ...... 6 Winter Surveys ...... Summer Surveys 10 Roost Sites...... and Nursery Colonies 10 Mist Net ...... 11 Sites ...... Museum Searches 17 ...... Statewide Distribution 17 Summary of Distribution...... 17 Comparison of ...... Records _ 17 Distribution ...... DISCUSSION 27 ...... Requirements 27 Habitat ...... Size and 28 Population Status ...... MANAGEMENT RECOMMENDATIONS 31 ...... General Recommendations 31 Habitat Protection ...... 31 Population Monitoring...... 32 Education and Recovery...... Programs 32 ...... Site-specific Recommendations 32 ...... U.S. Forest ervi ce 33 Bureau of Land Management...... 37 Private/State/Other ...... 39 ...... ACKNOWLEDGMENTS 42 ...... REFERENCES 43 ......
i CONTENTS (continued)
Page
APPENDICES 45 ...... Appendix A: Sources used to determine potential bat 46 hibernacula in central Oregon I ...... Appendix B: Museuins visited or contracted for additional bat 47 records ...... Appendix C: Habitat types and definitions used for mist 48 net inventories ...... Appendix D: Availability of maps for caves containing bat hibernacula and colonies 50 roosts, nursery ...... FIGURES
Number Page
1. Study areas surveyed for Townsend's Big-eared bats in Oregon between 1982 and 1986 4 ...... 2. Known of Townsend's in Oregon 19 distribution big-eared bat ...... TABLES
Number Page
1. Chronology of areas surveyed for Townsend's big-eared bat by Perkins between 1982 and 1986 5 ...... 2. Nufuber of sites successfully searched lor nilbernacula of Townsend's big-eared bat ...... 7 3. Bat species found during hibernacula searches between 1982 and 1986 7 ...... 4. Hibernacula of Townsend's big-eared bat found between 1982 and 1986 by 8 county ...... 5. Number of sites successfully searched for summer roosts and of Townsend's 10 nursery colonies big-eared bat ...... 6. Bat species found during summer roost and nursery colony between 1982 and 1986 12 searches ...... 7. Nursery colonies of Townsend's big-eared bat found between 1982 and 1986 by 13 county ...... S. Mon-nursery day and night roosts found for Townsend's between 1982 and 1986 by 14 big-eared bat county ...... 9. Number of Townsend's big-eared bats found at summer roost sites and nursery colonies between 1982 and 1986 ...... 15 10. Number of sites successfully mist netted for Townsend's between 1982 and 1986 15 big-eared bat ...... 11. Number of bats captured at summer mist net sites by 16 species ...... 12. Mist net sites for Townsend's big-eared bat between 1982 and 1986 by 17 county ...... 13. Previously unreported museum records for Townsend's in Oregon 18 big-eared bat ...... 14. Statewide distribution records for Townsend's big-eared bat in Oregon 20 ...... 15. Comparison of historical and present winter records Townsend's in Oregon 27 of big-eared bat central ......
iv DISTRIBUTION, STATUS, AND HABITAT AFFINITIES OF TOWNSEND'S BIG-EARED BAT (PLECOTUS TOWNSENDII) IN ORECO-N' J. Mark Perkins
ABSTRACT
A five-year survey of the distribution, status, and habitat affinities of Townsend's big-eared bat (Plecotus townsendii) in Oregon was conducted between 1982-7n-d [email protected], mines, bridges, and buildings were surveyed for winter hibernacula, summer nursery colonies, and day or night roosting bats. Water sites and cave or mine entrances were mist netted to identify areas of bat activity. Townsend's big-eared bats were found at 34 hibernacula and accounted for approximately 997 (94%) of the 1,062 bats found wintering in Oregon. Nine nursery colonies with about 970 Townsend's big-eared bats and 22 summer roost sites with 43 bats were found in the study area. Only six Townsend's big-eared bats were mist netted. Caves and cave-like structures, which provide critical habitat for hibernacula and nursery colonies of Townsend's big-eared bats in Oregon, are increasingly subjected to disturbance from recreational use and vandalism. Townsend's big-eared bats were not found or had greatly reduced numbers at many historic sites in Oregon. Critical hibernacula and nursery colonies for Townsend's big-eared bat are defined, and statewide distribution records are summarized. Management recommendations include habitat protection, population monitoring, and education of the public as well as federal and state land management personnel.
INTRODUCTION
The general ecology and distribution of bat species in Oregon was summarized by Maser and Cross (1981) and Maser et al. (1981). Cross (1976), restricted his bat survey to southern Oregon. Specific information is lacking on the current status, distribution and management guidelines of bat species in Oregon. This information is needed for state and federal agencies to maintain viable bat populations.
In March 1982, a five-year study was initiated by the Oregon Department of Fish and Wildlife through the Nongame Wildlife Program, to inventory those portions of Oregon not previously surveyed for bats by Cross (1976). The study objectives were to: 1. Determine the distribution of each bat species occurring in Oregon;
2. Determine comparative population levels of e ach species in Oregon;
3. Determine, if possible, habitat(s) necessary for viable populations of each species;
4. Locate critical reproductive, hibernating, and feeding sites;
5. Collect potentially useful ecological data; and
6. Develop management recommendations for each species and for critical. sites.
This report summarizes information on the Townsend's big-eared bat (Plecotus townsendii) from the survey conducted between 1982 and 1986, the work of Cross (1976), Maser and Cross (1981), and additional museum specimens. Hall (1981) recognizes two subspecies of Townsend's big-eared bat. P. t. townsendii is found west of the Cascade Mountains in Oregon; P. t. ingens occurs east of the Cascade Range. Maser and Cross (1981) recognize
I one subspecies - P. t. townsendii. have encountered at least two distinct color phases, but am reluctant to recognize subspecies on this basis alone.
In 1985, Townsend's big-eared bat (P. t. townsendii) was designated a federal candidate species (category 2) by the U.S. Fish and Wildlife Service (U.S. Fish and Wildlife Service 1985). This report provides statewide distribution records for this sensitive species, defines critical hibernacula and maternity colony sites, and recommends management guidelines to prevent further population declines of the Townsend's big-eared bat in Oregon.
STUDY AREA
The study area consisted of potential bat habitat throughout the State of Oregon, excluding the portions of southern Oregon surveyed by Cross (1976), with the exception of two limestone caves in Josephine County and a cave in
-2- the southern portion of Malheur County (Figure 1). The state was inventoried over broad geographic areas between 1982 and 1986 as shown in Table 1.
METHODS
To inventory Townsend's biq-eared bat. suitable habitat was identified as existing caves and mines. Barbour and Davis (1969) considered Townsend's
big-eared bat ". . . the most characteristic bat of caves and abandoned mine Local and tunnels . . ." biologists mineral experts were interviewed for leads to potential habitat. Public input was solicited through radio and television announcements and flyers posted throughout the study area. Additional sources used to determine potential bat habitat are included in Appendix A. Several museums were visited or contacted to obtain distributional records not reported by Maser and Cross (1981) (Appendix B).
Winter Surveys
Caves and mine adits were surveyed for hibernating bats from October to March most years. Sites were searched by two persons with lights at least once. Bats at hibernacula were quickly identified to species and counted. Bats, in general, were not handled to minimize disturbance. One or two voucher specimens were collected per population, if none from that population group already existed in museum collections.
Characteristics at the hibernacula were recorded, including approximate height from the floor, use of crevices or open areas, and use of twilight or dark zones. Some temperature and humidity measurements were also noted.
Summer Surveys
Summer inventories included (1) searches of caves, mines, buildings, and bridges for bat roosting sites, particularly nursery colonies, and (2) mist netting at isolated water areas and cave and mine entrances to determine bat species present.
-3- = Areas surveyed by Perkins 1982-1986
= Area surveyed by Cross (1976)
+ = Caves surveyed by Perkins in 1984 and 1985
ton or Ln,
at on Baker Grant L on
Lane
WESTERN OREGON ENTRAL OREGON EASTERN OREGON
Harney M.1h..r 005 Lak
.phin Ja kson K ... t
Figure 1. Study areas surveyed for Townsend's big-eared bats in Oregon between 1982 and 1986. Table 1. Chronology of areas surveyed for Townsend's big-eared bat by Perkins between 1982 and 1986
STUDY AREA SURVEY DATE(S) DESCRIPTION
Western OR 1982 Summer and winter survey of northwest Oregon: Benton, Cldckamas, Ciatsop, Coiumbia, Lincoin, Linn, Marion, Multnomah, Polk, Tillamook, Washington, and Yamhill Counties, excluding lands in federal ownership.
1983 Summer and winter survey of western Oregon: Coos, Douglas, and Lane Counties. 1984 Winter search for hibernacula in portions of Mt. Hood National Forest, Umpqua National Forest, and two caves in Josephine County.
1984 Summer and winter survey of the Mt. Hood and Willamette National Forests.
Central OR 1984 Winter search for hibernacula in north-central Oregon: Hood River, Jefferson, Sherman, and Wasco Counties. 1986 Summer and winter survey of central Oregon: Crook, Deschutes, Gilliam, northern Harney, Hood River, northern Klamath, northern Lake, Sherman, Wasco, and Wheeler Counties.
Eastern OR 1984 Summer and winter survey of northeast Oregon: Umatilla, Union, and Wallowa Counties, excluding lands in federal ownership. 1985 Summer and winter survey of eastern Oregon: Baker, Grant, Grant, Malheur, Morrow, Umatilla, Union, and Wallowa Counties. Nursery colonies were quietly visited and numbers estimated. If bats began to take flight, I immediately left the roost site. Data collected from nursery colonies included species, population estimate, type of roost structure, structure age, favored roosting site, surrounding vegetation, distance from water, and elevation.
Water sites and cave and mine entrances were mist netted in a variety of habitats to determine bat species present. Mist net sites were distributed throughout the study area with an effort made to adequately represent all counties and habitat types. Habitat definitions are summarized in Appendix C.
Bats captured in mist nets were identified to species, sexed, weighed, and released. A limited number of Townsend's big-eared bats were banded (Bonaccorso et a!. 1976). Other captured bats were punch-marked in the wing membrane for short-term identification (Bonaccorso and Smyth 1972). Voucher specimens of species other than Townsend's big-eared bat were collected where adequate numbers were netted. Data similar to that collected by Cross (1976) were collected at mist net sites.
RESULTS
Winter Surveys
A total of 478 caves, mines, buildings, and tunnels were searched for hibernating bats between 1982 and 1986. Bats were found at 43 sites; Townsend's big-eared bat was found at 34 (79%) of these sites or 7% of all sites searched (Table 2). All hibernacula located for Townsend's big-eared bat were in caves or mines. Townsend's big-eared bat accounted for 997 (94%) of the 1,062 hibernating bats located during this study. Additional species found are summarized in Table 3.
Over half of the wintering population of Townsend's big-eared bat was found in the central Oregon study area. The bats occupied the lava caves of Deschutes County on the Deschutes National Forest, Prineville BLM District, and adjacent areas in private ownership. A summary of the size and location of all hibernacula located is included in Table 4.
-6- Table 2. Number of sites successfully searched for hibernacula of Townsend's big-eared bat
STUDY SITES SITES SITES TOTAL TOTAL AREA SEARCHED WITH BATS W/PLECOTUS BATS PLECOTUS
Western OR 156 14 8 (4%)a 142 136 (96%)b
Central OR 109 19 118 (17%) 564 518 (92%)
Eastern OR 213 10 8 (4%) 356 343 (96%)
Total 478 43 34 (7%) 1,062 997 (94%)
a Percent of all sites searched. b Percent of total bats.
Table 3. Bat species found during hibernacula searches between 1982 and 1986
STUDY AREAS
SPECIES WESTERN OR CENTRAL OR EASTERN OR
Long-eared bat (Myotis evotis.) +
Small-footed myotis (Myotis leibii) + + Little brown bat (Myotis lucifugus)
Myotis species (Myotis Sp.) + + +
Fringe-tailed bat (Myotis thysanodes) +
Hairy-winged myotis (Myotis volans) +
Townsend's big-eared bat (Plecotus townsendii) + + +
+ Species noted during winter survey. Species not noted during winter survey.
-7- Table 4. Hibernacula of Townsend's.big-eared bat found between 1982 and 1986 by county
COUNTY SITE OWNERSHIP PLECOTUS DATE
Baker Weatherby Tunnel Private 1 10/20/84
I- am 11 ac as Ames/Bancrofit Mine USFS iPr-va'er i L If I '98-Li (T6S, R7E, S5)
Clackamas Fish Creek Cave USFS 12 1984
Crook Paulina Cave BLM 1 11/03/85
Deschutes Bat Cave #1 USFS 5 11/17/35
Deschutes Boyd Cave USFS 2 11/17/85
Deschutes Charcoal, Cave #2 BLM 2 11/13/85
Deschutes Charlie The Cave USFS 10 11/12/85
Deschutes Deg Cave USFS 5 11/13/85
Deschutes Lava River Cave USFS 5 11/11/35
Deschutes Lower Quarz Mtn. Cave USFS 26 11/08/85
Deschutes Mushroom Cave #2 USFS 1 11/08/85
Deschutes Pictograph Cave BLM 20 11/13/85
Deschutes Redmond Cave City of Redmond 1 01/10/86
Deschutes Skeleton Cave USFS 8 11/12/85
Deschutes Stookey Ranch Cave Private 245 01/11/86
Deschutes Stove Cave Private 1 11/14/85
Deschutes Wind Cave USFS 50 11/17/35
Douglas Scott Mtn. Caves BLM/Private 55 @1983 (T25S, R3W, S28)
Douglas Tenmile Mtn. Cave Private 2 1983
Douglas Ben Irving Reservoir Private 1 .1983
Grant Officer's Cave Private 134 11/03/85
-8- Table 4. Continued
COUNTY SITE OWNERSHIP PLECOTUS DATE
L ake Derrick Cave BLM 1 11/11/85
Lake Hairpin Cave BLM 1 11/11/85
Lane Blue River Cave Private 19 1983 (T16S, R4E, S29)
Lane Bohemia Mines Priv/USFS 25a 1983
Malheur Baker Cave BLM 2 02/20/85 (Saddle Butte)
Malheur Coyote Trap Cave BLM @00 02/20/85 (Saddle Butte)
Malheur Owyhee River Cave BLM 32 02/20/85 (Saddle Butte)
Malheur Rattlesnake Cave I BLM 3 02/19/85 (Saddle Butte)
Malheur Rattlesnake Cave II BLM 62 02/20/85 (Saddle Butte)
Malheur Tire Tube Cave BLM 20 02/20/85
Marion North Falls Cave State Park 1 1982 (Silver Creek)
Wallowa Mtn. Chief Mine USFS 23 01/15/84
a One mine had 22 Plecotus, three mines had one bat each.
-9- Three major hibernacula for Townsend's big-eared bat were found during this study. Stookey Ranch Cave, a privately-owned cave in Deschutes County, contained 245 Townsend's big-eared bats in 1986. Coyote Trap Cave, part of the Saddle Butte system in Malheur County, contained 200 Townsend's big-eared bats in 1985. The cave is under the jurisdiction of the Vale District of the RIM, Officer's Cave, a orivately-owned cave in Grant County. was used by 134 Townsend's big-eared bats in 1985. Maps of these and other cave systems in central and eastern Oregon are available as indicated in Appendix D.
Summer Surveys
The results of summer surveys conducted for Townsend's big-eared bats between 1982 and 1986 are presented in two sections: (1) roost sites and nursery colonies; and (2) mist net sites.
Roost Sites and Nursery Colonies
Bats were found at 296 (38%) of the 772 caves, mines, bridges, and buildings searched for summer day and night roosts and nursery colony sites (Table 5). Townsend's big-eared bat was located at 31 (14%) of the occupied sites, 4% of all sites searched. Caves and mines were the favored roost and nursery sites for Townsend's big-eared bat; only four buildings and one bridge were occupied by this species.
Table 5. Number of sites successfully searched for summer roosts and nursery colonies of Townsend's big-eared bat
STUDY # SITES # SITES SITES TOTAL TOTAL AREA SEARCHED WITH BATS W/PLECOTUS # BATS PLECOTUS
(1%)b Western OR 357 157 10 (3%)a 7,186 91
Central OR 196 65 8 (4%) 7,603 458 (6%)
Eastern OR 219 74 13 (6%) 3,968 464 (12%)
Total 772 296 31 (4%) 18,757 1,013 (5%)
a Percent of all sites searched. b Percent of total bats.
_10- Over 18,500 bats of 11 species were located during summer searches, including 1,013 (5%) Townsend's big-eared bats. Table 6 summarizes the species found at roost sites and nursery colonies by study area. Nine species were found in western and central Oregon, 10 species in eastern Oregon. Townsend's big-eared bat was one of six species found in all three study
a.,reas
Nursery colony locations and summer roost sites are summarized in Table 7 and 8 respectively. Two nursery colonies (approximately 80 bats) and eight roost sites (11 bats) of Townsend's big-eared bat were located in western Oregon. Four nursery colonies (450 bats) and four roost sites (eight bats) of Townsend's big-eared bat were found in central Oregon. Two large nursery colonies, with 250 bats each, were found in caves in Deschutes and Malheur Counties. Overall, nine nursery colonies with 970 bats and 22 summer roost sites with 43 bats were found for Townsend's big-eared bat between 1982 and 1986 (Table 9).
Mist Net Sites
A total of 267 isolated water sites and cave and mine entrances were mist netted in summer between 1982 and 1986. Bats were found at 164 (61%) of the sites (Table 10). Townsend's big-eared bat was netted at only two (1%) of the mist net sites and was observed, but not netted, at one site in the Imnaha Canyon of Wallowa County.
Of the 1,090 bats of 13 species collected by mist net, only six (<1%) were Townsend's big-eared bats. Table 11 summarizes the numbers and species captured by study area. No Townsend's big-eared bat were netted in western Oregon and only one male was netted over water in the central Oregon study area (Table 12). Three males and two females were netted at mine adits along. the Powder River in Baker County and the species was observed, though not netted, along the Burnt River in Baker County and in the Imnaha Canyon of Wallowa County in the eastern Oregon study area. Table 6. Bats species found during sunner roost and nursery colony searches between 19B2 and 1986
WESTERN OR CENTRAL OR EASTERN OR
SPECIES Roost Colonies Roost Colonies Roost Colonies
Pallid Bat + + + + + (Antrozous pallidus
Big brown + bat + + + + + (Eptesicus ±oscus)
California myotis + + cal iforni anus
Long-eared bat + + + evotis)
S-nall-footed myotis + + leibii)
brown + Little bat + + + + + lucifugus;
Fringe-tailed bat + + + thysanodes
Myotis species + + (n2@ Sp.)
Hair,@-winged bat + + + + + (n)2LI@ volans)
Yuna bat + + + + + (nELL yumanensis
Townsend's big-eared bat + + + + + (Plecotus townsendii
+ = Species noted during swmr survey. = Species not noted during sunner survey. Table 7. Nursery colonies of Townsend's big-eared bat found between 1982 and 1986 by county
COUNTY SITE OWNERSHIP PLECOTUS DATE
Deschutes Barlow Cave Private 50 1986
Deschutes Charlie The Cave USFS 250 1 986
Douglas Mowich Cave USFS 40 1983
Douglas Unnamed Cave USFS 40 1983
Harney Roaring Springs Cave BLM 50 i986
Malheur Cat-Be-Gone Cave BLM 250 07/14/85
Malheur Finally A Cave BLM 150 07/14/85
Wallowa Mine (Hell's Canyon RNA) USFS 40 05/07/85 (T3N, R48E, S13)
Wheeler Service Creek (bridge) DOT 100 1986
-13- Table 3. Non-nursery day and night roosts found for Townsend's big-eared bat between 1982 and 1986 by county
COUNTY SITE OWNERSHIP PLECOTUS DATE
Clack amas Ames/Bancroft Mine USFS/Private 3 1984 (T6@_ R7F, S5)
Deschutes Redmond Cave City of Redmond 1 1986
Deschutes Stookey Ranch Cave (Bend) Private 5 1986
Deschutes Young's Cave Private 1 1986
Lake Tree Cave BLM 1 1986 (Sqaw Butte)
Lane Bridge DOT I male 1983
Lane Bridge DOT 1 male 1983
Lane Bridge DOT I female 1983
Lane Bridge DOT I female 1983
Linn Detroit (building) USFS 1 1982
Linn Fernview Campground USFS 1 1982 (Building)
Malheur Baker Cave BLM 1 male 05/16/85 (Saddle Butte)
Malheur Can Cave BLM 3 females 05/16/85 (Saddle Butte)
Malheur Cave Creek Mines BLM 2 males 07/22/85
Malheur Coyote Trap Cave BLM 9 males 07/14/85 (Saddle Butte)
Malheur Evening Cave BLM 1 female 05/17/85 (Saddle Butte)
Malheur Tire Tube Cave BLM 2 males 05/16/85 (Saddle Butte)
-14- Table S. Continued
COUNTY SITE OWNERSHIP PLECOTUS DATE
Malheur Twin Pit Cave (Saddle Butte) BLM 1 male 07/14/85 Malheur Twin Pit Extension BLM 2 females 05/17/85 loaddle@@ UU1 Butte\0 46 1
Marion Jawbone Flat (shack, USFS 2 1984 warehouse)
Wallowa Mtn. Chief Mine USFS 2 males 05/06/85 (Hell's Canyon RNA)
Wallowa Temperance Creek Mine USFS 1 female 08/17/85 (Hell's Canyon RNA)
Table 9. Number of Townsend's big-eared bats found at summer roost sites and nursery colonies between 1982 and 1986
ROOSTS AND STUDY ROOSTS NURSERY COLONIES NURSERY COLINIES AREA #Bats (#Sites) #Bats (#Sites) #Bats (#Sites)
Western OR 11 (8) 80 (2) 91 (10)
Central OR 8 (4) 450 (4) 458 (8)
Eastern OR 24 (10) 440 (3) 464 (13)
Total 43 (22) 970 (g) 1,013 (31)
Table 10. Number of sites successfully mist netted for Townsend's big-eared bat between 1982 and 1986
STUDY # SITES SITES SITES TOTAL TOTAL AREA SAMPLED W/BATS W/PLECOTUS BATS PLECOTUS
Western OR 129 79 0 408 0
Central OR 45 31 1 348 1
Eastern OR 93 54 1 334 5
Total 267 164 2 (1%)a 1,090 6 ( a Percent of sites sampled. b Percent of total bats. _15- Table 11. Number of bats captured at summer mist net sites by species Western OR Central OR Eastern OR Total SPECIES Bats Sites) Bats Sites) Bats Sites) Bats sites) 0 (0) 15 (3) Pallid Bat 0 (0) 15 (3) (Antrozous pallidu 87 (16) 27 (17) 176 (45) Big brown bat 62 (12) (Eptesicus fuscus) (26) 350 (51) Silver-haired bat 133 (8) 104 (17) 113 (Lasionycteris noctivagans) 20 (10) 59 (20) Hoary bat 10 (1) 29 (9) (Lasiurus cinereus) 7 48 (19) California myotis 32 (6) 9 (7) (6) (Myotis californianus) 21 (16) 68 (33) Long-eared bat 26 (8) 21 (9) (Myoti evotis) 3 (5) 17 (7) Small-footed myotis 0 (0) (2) 14 (Myotis leibii) 81 (19) 209 (55) Little brown bat 108 (25) 20 (11) (Myotis lucifugus) 9 (1) 11 (3) Fringe-tailed bat 2 (2) 0 (0) (Myotis thysanodes) 34 (15) 112 (34) Hairy-winged bat 28 (4) 50 (15) (Myotis volans) 7 7 2 (2) 16 (6) Yuma bat (2) (2) (Myotis vumanensis) 3 2 1 (1) (3) Western pipistrelle 0 (0) (2) (LjEj@. hesperus) 5 6 (2) Townsend's big-eared bat 0 (0) .1 (1) (1) (Plecotus townsendii) Table 12. Mist net sites where Townsend's big-eared bat were found between 1986 and 1982 by county COUNTY SITE OWNERSHIP # PLECOTUS DATE Baker Keeney Mine BLM 5 (3M, 2F) 07/19/85 Crook Cave Basin BLM I (M) 07/12/86 (T17S, R23E, S19) Museum Searches Fourteen museums were contacted or visited for records not previously reported by Maser and Cross (1981) (Appendix B). Fourteen new records for Townsend's big-eared bat were found at the institutions listed in Table 13. These include new records for Clackamas, Deschutes, Harney, Umatilla, Union, Wallowa, Wasco, and Wheeler Counties. Statewide Distribution Summary of Distribution The known, statewide distribution of the Townsend's big-eared bat is shown in Figure 2, with accompanying locations listed by county in Table 14. The distribution is based an (1) results of this studyincluding hibernacula, day and night roosts, nursery colonies, mist net sites, and new museum records; (2) museum and literature records summarized by Maser and Cross (1981); and (3) sites reported from southern Oregon surveys by Cross (1976). Comparison of Distribution Records Museum and literature records from Maser and Cross (1981) and additional, museum records uncovered during the course of this study (Table 13) accounted for 55 known sites for Townsend's big-eared bat in Oregon. These included hibernacula previously known at Oregon Caves in Josephine County, Paulina Cave in Crook County, and Boyd Cave in Deschutes County; and a nursery colony at Roaring Springs Cave in Harney County. -17- Table 13. Previously unreported museum records for Townsend's big-eared bat in Oregon COUNTY COLLECTION SITE MUSEUM Clackamas West Linn Portland State University (PSU) Clackamas Butte Creek Falls Portland State University (PSU) Deschutes 14 miles southeast of Bend San Diego Museum of Natural History (SDMNH) Deschutes Boyd Cave Walla Walla College (WWC) Deschutes Twin Skylight Cave Portland State University (PSU) Harney Diamond Craters Malheur Environmental Field Station (MEFS) 'Umatilla 5 miles east of Milton Walla Walla College (WWC) Umatilla 15 miles east of Milton University of California at Berkeley (UCB) Union Ice Caves Eastern Oregon State College (EOSC) Union Mt. Harris Eastern Oregon State College (EOSC) Union 6 miles north of Elgin Walla Walla College (WWC) Wallowa Joseph Creek Canyon Washington State Univesity (WSU) Wasco Maupin San Diego Museum of Natural History (SDMNH) Wheeler 15 miles east of Antelope University of California (UCB) Hibernaculum Nursery Colony Other (includes roost sites, mist net collections, museum records, and literature records) 7-@ Ir A ------ Figure 2. Known distribution of Townsend's big-eared bat in Oregon. _19- 9L6T SSOJO W SS 'MZT'd 'Wi kun3 9Z61 SSO-AO J13 '9ES 'METb 'Secl Xun3 9Z6T SSO-AO M 3S 'TZS 'MtU 'SZCi 9Z6T SSWO 3S '8ZS 'MtU 'S6Ci 9Z6T SMAD MS 'STS 'MtTb 'SLCi (3S 'tS 'MVT@ 'StICI) 9161 SSOJD (N) qOuPd SUN ;SP03 X.AinD (K) (6TS '@EZ@ 'SLII) SUL >PG d ULSP9 @APO @oojo (TS61 SS0J3 i Aaspw) nso !SLIL@J@d (H) aAP3 PuUnPd @OOAo (196T sso.Ao T jasew) nso (c)) qDpas UouUPO dOs4PLO SUL).A@d (H) GAPO @[email protected] 4SL4 SPWPN3PL3 (SS '31b 'S91) Su L VE)d 'H) allLW J@DA:)UPG/S@WV SPLLIPPP LO (186T SSOJD T J@SPW) wNsn 'HNWSd !SUL@Jad (0) JaAJPO '@APD SJUP-A9 SP wPPP LO (SUL VB d) nSd (0) SLLPA azqng SPWP@DPLO (SULI.A@d) nSd (0) UUL@ ;SaM SPWP)32[0 @A@60 (T861 sso.Ao 12 -Aaspw) nso (0) PUPLSI UojUaq (T96T SSO-40 I -A,?SPW) nSO (0) S.LLLPAaOD 10 q:@.AOU SaL@w C Uolues (T86T SSO-to Aaspw) nso (0) SLLLPAtOO Uoquao SLJL@-Aad (H) Puuni XqJ@Q4P@M A@@Pq (.AaA L@ juAnS) ' [email protected]@d (0) BULW 'uqKi daaqS Aa@pe (.I@ALb JWAOd) SULN.A;),t (w) auLw xau;;)@, AaNP q 30noS NOUVJO@ AiNA03 N H !19U ZSLW W .,.Aaqqo = 0 !Zsoob !XjasjnN !wnLnoPuj@q[H = ,uo5ajo uL qpq [email protected]@-BLq s,puasumoi JOJ SP.A00BA U0L;[email protected] aP@M@q?;S 'VI aLqpi Table 14. Continued COUNTY LOCATION SOURCE Curry Upper Rogue River Valley (0) Bailey 1936 (Maser & Cross 1981) Deschutes Barlow Cave (N) Perkins Deschutes Bat Cave #1 (H) Perkins Deschutes 6 miles SE of Bend (0) PSMHN (Maser & Cross 1981) Deschutes 5 miles SE of the Deschutes, OSU (Maser & Cross 1981) near Bend (0) Deschutes 14 miles SE of Bend (0) SDMNH (Perkins) Deschutes Boyd Cave (H) Perkins, WWC (Perkins) Deschutes Charcoal Cave #2 (H) Perkins Deschutes Charlie The Cave (H, N) Perkins Deschutes Deg Cave (H) Perkins Deschutes Edison Ice Caves (H). Perkins Deschutes Lava River Cave (H) Perkins Deschutes Lee's Cave (H) Perkins Deschutes Lower Quartz Mtn. Cave (H) Perkins Deschutes Mushroom Cave #2 (H) Perkins Deschutes Pictograph Cave (H) Perkins Deschutes Redmond Cave (H, R) Perkins Deschutes Skeleton Cave (H) Perkins Deschutes Stookey Ranch Cave (H, R) Perkins Deschutes Stove Cave (H) Perkins Deschutes Twin Skylight Cave (0) PSU (Perkins) Deschutes Wind Cave (H) Perkins Deschutes Young's Cave (R) Perkins -21- Table 14. Continued COUNTY LOCATION SOURCE Douglas Ben Irving Reservoir (H) ?erkins Douglas Mowich Cave (N) Perkins Douglas 10 miles east of Roseburg (0) OSU (Maser & Cross 1981) i Douglas Scott Mtn. Caves (H) Perkins (T25S, R3W, S28) Doug'. as Tenmile Mtn. Cave (H) Perkins Douglas Unnamed Cave (N) Perkins Grant officer's Cave (H) Perkins Harney Diamond Craters (0) MEFS (Perkins) Harney Malheur Cave (H) USNM (Maser & Cross 1931) Harney 3.3 miles S of Princeton (0) PSMNH (Maser & Cross 1981) Harney Roaring Springs Cave (N) uressman & Reed 1938 (Maser & Cross 1981); Perkins Jackson T34S, RlE, S5, ME (N) Cross 1976 Jackson 2 miles west of Gold Ray PSMNH (Maser & Cross 1981) Dam (0) Jackson 11 miles SE of Lake Creek (0) PSMNH (Maser & Cross 1981) Jackson Little Butte Creek (0) PSMNH (Maser & Cross 1981) Jackson 7 miles SW of Medford (0) PSMNH (Maser & Cross 1981) & 1ilackson Prospect (0) OSU (Maser Cross 1981) Josephine Oregon Caves (H) OSU, USNM (Maser & Cross 1981) Josephine Baldy Mt. Cave (N) Cross 1976 (T36S, R5W, S27, SW) Josephine Jone's Garage (R) Cross 1976 (T37S, R5W, S22, SW) Lake T35S, R23E, S15, SW (R) Cross 1976 Lake @Oerrick Cave (H) Perkins -22- Table 14. Continued COUNTY LOCATION SOURCE Lake Hairpen Cave (H) Perkins Ldke Tree Cave (R) Perkins Lane Blue River Cave (H) Perkins Lane Creswell (0) USNM (Maser & 'loss 1981) Lane Eugene (0) Bailey 1936 (Maser & Cross 19,31) Lane 11 miles west of PSMNH (Maser & Cross i921) Junction City (0) Lane MacKenzie Bridge (0) USNM (Maser & Cross 1981) Lane Vida (0) USNM (Maser & Cross 1981) Lane T21S, RI.E, S20 (R) Dyck (Perkins 1983) Lane T21S, RIE, S7 (R) Dyck (Perkins 1983) Lane T22S, R2E, S30 (R) Dyck (Perkins 1983) Lane T22S, R3W, S31 (R) Dyck (Perkins 1983) Lane Bohemia Mines (H) Perkins L ane 4 Bridges (R) Perkins Linn 1.5 miles north of Big Lake (0) PSMNH (Maser & Cross 1981) Linn Fernview Campground (R) Perkins Linn 3 miles SW of Shedd (0) OSU (Maser & Cross 1981) Linn Detroit (R) Perkins Malheur Baker Cave (H, R) Perkins Malheur Bogus Lake (0) PSMNH (Maser & Cross 1981) Malheur Cascade Reservoir (M) Cross 1976 Malheur Can Cave (R) Perkins Malheur Cat-Be-Gone Cave (N) Perkins -23- (186T -SSO-AO 12 -ADSL)WO SV61 q1008 (0) .1ajPmaa.A4-UojL@@jl P L L @lPwn (TS61 SS0.tO @ A@SPW) HNWSd (O) @00WPLLu @00wp L L U (T86T SSOJD T JaSPVl) CiSO (0) WGLP4DN looWPLHi (TS61 SSO-AD @ .40SPWO 9C6T 4@BP9 (0) PuPi4-Wd qPwOu-40w SUL)Pad (@APO @88.43 JDAL@S) (T86T SS0.AO q A@S'?W) HNWSd (H) DAPO SLLPJ q4.WN UOWPW SUL@JBd IeL@ auoqmpp Uowpw SUL@J@d 8) SBULW JGaJO BAPO tna4LPW SUL@J@d (8) aAP3 6ULUaA3 Anaq Lpw SUL@J@d (d 'H) aAP) aqni @.ALJ Anaq LvIN, 9L61 SSOJO (T86T SSOJD 7 JBSPW) OSOS (O 'W) ITS '3Ztb 'SZEi An@4LPW (T86T SSOJO I JaSPW) HNWSd (0) LLPj4sam maq Lpw (THT SSOJO q JasPW) HNWSd (0) aw08 @o 3S SaBW S'C Anaq LPW SU L).Aad (H) II 8APO a@PUS@L;;P@ AnDq LPW SUPI@Aad (H) I ;)APO @@Pusi)L;4P@ inaq LPk, SU L@JE)d (H) @APO XDAL@ GaqfiMO Atlaq LPw (186T Sso-AD I? A@SPW) HNWSd (0) AaqeJ3 Uppor An94LPN 9L6T Ss0J3 (T86T SSOJO T JaSPW) DSOS (O IV,) uo4upo dwpo RSJOH anaqLPV,' SUL)J@d (N) aAPO V 4LLPuLd An@qpj@., SUL)Jad UOLsua4y3 Z@d uLml Anaq[pi,. S U.L Y,.l 9 d (b) aAPO 4@d U.LMJ An@ q I P1%, SUL)aGd (6 'H) @APO dp.Ai alofioo jnaq[pw (T861 SSOJO ABSPW) WNSn (0) PJDD @o Ms S;L@w ST AnaqiPw 3ovos Nolivool AiNnoo panU.LjU0O -VT @Lqpi Table 14. Continued COUNTY LOCATION SOURCE Umatilla 5 miles E of Milton (0) WWC (Perkins) Umatilla 15 miles east of Milton (0) USB (Perkins) Union Ice Caves (0) ESOC (Perkins) Union Mt. Harris (0) ISOC (Perkins) Union 6 miles north of Elgin (0) WWC (Perkins) Wallowa Mtn. Chief Mine (H, R) Perkins (Hell's Canyon) Wallowa Temperance Creek Mine (R) Perkins (Hell's Canyon) Wallowa T3N, R48E, S13 (N) Perkins (Hell's Canyon) Wallowa Imnaha River Canyon (0) Perkins Wallowa Joseph Creek Canyon (0) WSU (Perkins) Wallowa Parad-ise, (0) Bailey 1936 (Maser & Cross 1981) Grande Ronde Canyon Wasco 6 Miles East of Antelope(O) OSU (Maser & Cross 1981) Wasco Maupin (0) SDMNH (Perkins) Wasco Memaloose State Park (0) PSMNH (Maser & Cross 1981) 2.5 miles east of Mosier Wasco 8 Miles S, 8 miles west of OSU (Maser & Cross 1981) The Dalles (O) Washington 4 Miles SE of Gaston (0) OSU (Maser & Cross 1981) Washington Tigard (0) PSMNH (Maser & Cross 1981) Wheeler 15 miles east of Antelope (0) UCB (Perkins) Wheeler Service Creek (N) Perkins -25- Cross (1976) surveyed Curry, Josephine, and Jackson Counties and reported Townsend's big-eared bat at six roost sites in the tri-county area, and three nursery colonies including a 400-bat colony in Coos County. I surveyed two caves in Josephine County for hibernacula in 1984, but found no bats. Cross (1976) also found one roost site in southern Lake County and mist netted Townsend's big-eared bat at three sites in southern Malheur County. During the course of this study, I found Townsend's big-eared bat at only two sites where it was previously reported in the western Oregon study area; both sites at the western edge of the Cascade Mountains. Jeff Pratt reported seeing at least two Townsend's big-eared bats at Grant's Park Cave in Carver; however, no bats were present when I visited the area the following weekend. A hibernaculum with only one Townsend's big-eared bat was located at the North Falls Cave in Silver Falls State Park, where Townsend's big-eared bat had been reported by Maser and Cross (1981). The Harney County nursery colony, first reported by Cressman and Reed (1938), was found active during this survey, but only on bat was found at the hibernaculum at Paulina Cave in Crook County, and two bats at the Boyd Cave hibernaculum in Deschutes County. Wintering populations throughout the central Oregon study area appear to be declining. Table 15 compares bat counts made in the 1960's with results from this study for several central Oregon hibernacula. Populations had previously been reported from Troy (single bats), Milton-Freewater (nursery), and Jordan Crater (single bats). I checked these sites in 1984 and again in 1985 but found no bats of this species. No Townsend's big-eared bats were found in Wasco, Union, or Umatilla County where they were previously reported. The species appears to have been extirpated throughout much of its former range in western Oregon; no bats were found in Clatsop, Tillamook, Multnomah, Washington, or Benton Counties despite previous records. -26- Table 15. Comparison of historical and present winter records of Townsend's big-eared bat in.central Oregon SITE HISTORICAL VS PRESENT VS Paulina Cave 80 I Officer's Cave 2--+uU 134 Lava River Cave 5 5 Lee's Cave 20 ? Skeleton Cave 20+ 8 Boyd Cave 10 2 Wind Cave ? 50 Deg Cave ? 5 Bat Cave ? 5 Malheur Cave 20 0 Edison Ice Caves 50+ 7 Townsend's big-eared bat has never been reported for Lincoln, Yamhill, Polk, Coos, Hood River, Sherman, Gilliam, Morrow, Jefferson, or Klamath Counties. The species was found for the first time in Baker and Grant Counties during this survey. DISCUSSION Habitat Requirements This study supports the contention of Barbour and Davis (1969) that Townsend's big-eared bat is the most characteristic bat of caves in the western United States. Caves and cave-like structures are a critical habitat for this species, both as hibernacula in the winter and as roosts for summer nursery colonies. To date, Oregon's caves have not been managed specifically as wildlife habitat and are subject to increasing disturbance from recreational use as well as outright vandalism. -27- Mist net results do not allow for an adequate evaluation of feeding habitat preferences in Townsend's big-eared bat. Only six Townsend's big-eared bats were captured using this method. It is obviously not an effective tool for monitoring populations of this species. Barbour and Davis (1969) speculate that the echolocation system in Townsend's big-eared bat may be sufficiently refined to allow even for the detection and avoidance of the fine filaments used in mist nets. Population Size and Status I estimate the total Oregon population of Townsend's big-eared bat to be approximately 2300-2600 bats. This is based on counts of nurseries, hibernacula, and individual bats from roosts and mist net captures made during this study as well as the results of the southern Oregon survey by Cross (1976). The colonies found indicate Oregon's population of Townsend's big-eared bat is as follows: southwestern Oregon = about 800-900 bats at four to six sites; northwestern Oregon = 300-400 bats at nine sites (all but one are USFS); central Oregon = 500-600 bats at nine sites (one BLM, one ODFW, three private and four USFS); northeastern Oregon = 100 bats at three to four U-SFS BLM); sites (all or and southeastern Oregon = 500-600 bats at two to three sites (all but one BLM). The population is fragmented in distribution, being restricted to areas of suitable cave or cave-like habitat, and is subject to increasing human disturbance, to which this species seems especially intolerant. The population of Townsend's big-eared bats wintering in western Oregon seems particularly depleted and is restricted to the Cascade and Calapooya Mountains. Only 136 hibernating bats were located in western Oregon during this study: in Clackamas County at the Ames/Bancroft Mine (21) and Fish Creek Cave (12); in Marion County at North Falls Cave (1); in Lane County at Blue River Cave (19) and the Bohemia Mines complex (25); and in Douglas County at Scott Mountain Caves (55), Tenmile Mountain Cave (2), and Ben Irving Reservoir (1). An additional 20 bats have been reported at the Oregon Caves hibernaculum in Josephine County. -28- it's unclear where the western Oregon population summers, as only two nursery colonies were located in the western Oregon study area. Only 40 bats were found at the colony at Mowich Cave and approximately 40 bats were reported at an unnamed cave in Douglas County. Cross (1976) found three nursery colonies in a survey of Curry, Josephine, and Jackson counties. This southwest Oregon population appears somewhat more stable. The Coast Hills Ranch and Baldy Mountain Cave colonies contained 400 and 200 bats respectively. The study indicates that the central Oregon population around Fossil and Antelope has been extirpated. The summer roost was at an abandoned school house about three miles east of Camp Hancock. Visits by OMSI students and others probably harassed the bats from this roost. None were noted at other potential sites in the area. Summer populations reported from the Catlow Valley, Clarno, and Antelope areas were not found at potential hibernacula sites. It is known that the Catlow Valley nursery was visited as recently as 1980, but Clarno and Antelope populations have not been noted since about 1980. The populations of Grant County and Harney County are small (less than 200) and susceptible to rapid decline from human disturbance at roost sites. Deschutes,and Lake County populations are at levels that could be considered stable, although declines have been noted at hibernacula in this area. Management of the habitat is necessary to ensure that the populations continue to be stable. Eastern Oregon populations of this species may be centered in only two areas. The largest is in the Saddle Butte System, probably numbering about 500+ individuals. This is based on estimates of the female population which comprises about one-half of the total. Males from this population may be among those netted or collected and recorded by Maser and Cross (1981). Captures in southern Harney County most likely came from reported populations in caves at the Catlow Valley Rim at Roaring Springs Ranch and from the more northerly Malheur Cave. It is highly probable that those recorded from Jordan Craters and south and east of Saddle Butte are part of the Saddle Butte -29- population that exhibit summer migration, probably to ease foraging competition around the nursery sites. The Owyhee River Canyon and J ,ordan Crater provide the closest known areas with acceptable roost sites. Townsend's big-eared bats noted in northern Malheur and southern Baker Countiesare probably part of a population centered in mines and caves in the Mormon Basin. Considering the extensive mining which occurred there, this is highly possible. Townsend's big-eared bats noted along the Powder River may be a local population that is suffering from recent mining impacts. The area where the females and young were noted has an active mine which, according to the owners, had bats in it until blasting was resumed. Several other adits exist in the area and still support a small population. The Hell's Canyon-Imnaha Canyon population numbers about 100. This population may be part of an Idaho group which I've observed in caves above Hells Canyon Dam. Only one winter hibernaculum is presently known (Mtn. Chief Mine) and contains about 20 bats. The summer nursery roost site is in a mine which is later used by the little brown bat (Myotis lucifugus). This adit occurs along a hiking trail and is subject to some human disturbance. When I visited this mine in May 1985, about 40 to 50 females were present. A subsequent visit in late July resulted in no Townsend's big-eared bats, but a colony of little brown bats was using another part of the tunnel. A record of a single female from Joseph Creek Canyon, around 1976, and a report from a Dan Wiggins of Wallowa County that a cave with bats is present in the canyon indicates a population may be present here and could be part of that which Bailey (1936) noted at Paradise. The colony noted in Umatilla County by Booth (1945) could not be found and is presumed extirpated. This leaves two definite and three probable areas with populations of Townsend's big-eared bat in eastern Oregon, which in turn are highly dependent upon a few roosts for survival. -30- MANAGEMENT RECOMMENDATIONS General Recomendations Habitat Protection It is imperative that sites with large numbers of hibernating bats and those with day roosting females and young be protected. Those caves which contain five or more hibernating or day roosting bats should be considered for seasonal closure to all recreational and most scientific activities (winter from 1 November to 1 April; summer from 1 May to 31 August). Closures could vary from road use restrictions on unplowed roads or recreation trails to road gating or signs placed within the cave entrance noting the closure and the importance of not disturbing the bats. Until bat use is determined, caves, mines or rimrock sites should not be opened to recreation or mining. These types of habitat are prime areas for Townsend's big-eared bats, fringe-tailed bats (M. thysandoes) and nursery colonies of other bat species. Timber and grazing buffer zones should be established around occupied cave and mine entrances or cliffs. Buffer zones will help prevent unnecessary public access and provide cover to protect bats from aerial predators. Pesticide or herbicide use is not recommended in the vicinity of known bat roosts, or in areas of high insect activity, as it would adversely affect bat populations. These bats rely entirely on insects and arthropods as a food source, which they capture in flight or glean from foliage. Federal and state agencies should protect bat colonies found in buildings within their jurisdiction. To prevent unwanted employee or public interaction with bats, it is easiest to isolate the areas the bats prefer to use from the rest of the building. Attempts to seal out bats (particularly from old wood or stone structures) are not successful, as they can gain access through a variety of entrances. _31- Population Monitoring Caves with winter and/or summer populations should be monitored at least biannually but not more than annually to detect population shifts from one cave to another and to determine the adequacy of protection measures. Results which show consistently declining numbers during the first three monitoring efforts, or a large decline (>15%) the first biannual monitoring, probably indicate additional disturbances and a higher degree of protection may be required. Statewide monitoring should be done by qualified researchers to minimize disturbance. Flexibility is needed in the protection plan to immediately address problems as they arise. Funding on a cooperative, long-term basis (50-10 years) is needed for monitoring and private land acquisition. Education and Recovery Programs Training sessions for wildlife biologists and resource personnel should be held to introduce and familiarize them with bat species, habitat, and general, ecological principals in order to effectively involve each departmental district with this sensitive species. Cooperative action is needed to begin a statewide recovery program to assure the viability of remaining Townsend's big-eared bat populations. The success of such programs for other bat species such as the gray bat (Myotis grisescens) and the Indiana bat (M. sodalis) demonstrate that efforts pay off as populations recover in a timely manner. Site-Specific Recomendations Specific management recommendations and ecological notes for the Townsend's big-eared bat and selected sites follow and are organized by ownership: -32- U.S. Forest Service 1. Mt. Hood National Forest Fish Creek Cave, Estacada Ranger District: This is a hibernaculum for about 10-12 Townsend's big-eared bats. Protection is presently given, but monitoring and future guarantees are needed. Ames/Bancroft Mine Clackamas Ranger District: This hibernaculum for approximately 20 Townsend's big-eared bats is the largest of three such sites in Clackamas County. A letter has been written encouraging a cooperative agreement with the owner(s) to protect and minimize disturbance during the winter months. 2. Umpqua National Forest Mowich Cave, Diamond Lake Ranger District: This site serves as a night roost for females and young of Townsend's big-eared bats. Public visitation should be limited to the hours of 8 a.m. to 7 p.m. during the spring and summer seasons. Monitoring of this site is needed. Diamond Lake, Diamond Lake Ranger District., Four maternity colonies exist in three U.S. Forest Service buildings: a warehouse, the information center, and a rented structure housing a store and restaurant. More than 700 individual bats of four species use this site. All colonies need to be protected and monitored. Bohemia Mines, Cottage Grove Ranger District: Alan Dyck has attempted to establish a cooperative agreement with the mine owner whose adits contained 22 hibernating Townsend's big-eared bats. -33- 3. Deschutes National Forest Deg and Charlie The Cave (Arnold Cave System): Hibernating bats numbered 15 in these two caves, one of which had a new passage opened by entrance digging (potholing?). Charlie the Cave had a major. summer colony of about 200 Townsend's big-eared bat. Apparently these two caves serve as alternate roosts for this colony as Charlie Larson noted them in Deg Cave a few summers ago. Deg and Charlie The Cave need administrative summer closures by road gating to prevent disturbance to the nursery colony. Both these caves are somewhat remote parts of the Arnold System, but are found easily by using the references in Appendix A. I noted at least five other visitors to these caves during the two visits I made in the summer of 1986. This indicates somewhat heavier use than I at first suspected. New passages discovered in Charlie The Cave have attracted members of the organized caving community. Increased use of the caves is highly probably due to their proximity to Arnold Ice, Bat'and Wind Caves. Gating is the only other regulatory mechanism tried, but in remote areas gates have been vandalized, and some gate structures restrict bat passage or wind flow, important to temperature regulations. Wind and Bat Caves (Arnold Cave SXIL22@_: Wind Cave is an extremely important hibernaculum for Townsend's big-eared bats. The majority of hibernating bats were located in the very terminus of Wind Cave. Apparently few people tour this far in, especially in winter. I did note two or more cars at the Wind Cave parking area during each of my trips into that end of the Arnold System. Summer bats have apparently been harassed from Bat Cave. These two caves should be administratively closed from I November to 1 April to prevent disturbance. The road leading -34- to Wind Cave needs to be gated and signed, and a sign should be placed inside the entrance to Wind Cave requesting cooperation from visitors to this hibernacula. Skeleton and Boyd Caves (Skeleton Cave Area): Boyd Cave could remai . n ooen Year round for recreation as bat use is presently minimal. Skeleton Cave, an important hibernaculum, shows the effects of vandalism in fire pits within the cave, extensive litter, and use of cave areas as toilet facilities. Jim Anderson (pers. comm.) indicated that Skeleton Cave previously contained higher numbers of hibernating bats. He believes increased visitation and vandalism were the obvious causes for. decline. A gate and explanatory sign at the road leading to Skeleton Cave should be considered, as well as a sign posted inside the cave entrance. The caves should be administratively closed from 1 November to 1 April to prevent disturbance. Edison Ice Caves: In 1984, Dick Pugh, a high school biology teacher, skied to these caves and noted about 50 Townsend's big-eared bats. Blizzard conditions aborted my trip, but his report indicates a small population in the local, area. If this proves to be accurate, I suggest that the trail not be a part of winter recreational use. Summer searches found indications of heavy summer recreational use but no bats. There is a substantial lava flow in this area, but these caves are the only ones known. This area probably deserves further study. The caves should be administratively closed from I November to I April. A sign inside the cave-entrance should also be considered. Lower Quartz Mountain Cave (Southwest Deschutes This cave held a good number of Townsend's big-eared bats and Myotids. It is the largest concentration of non-Plecotid hibernating bats presently known in Oregon. The cave location is readily noted in the guidebook to the National Speleological Society 1982 convention, An Introduction to the Caves of the -35- Bend Area. This important hibernaculum should be administratively closed 1 November to 1 April. Mushroom and Lee's Cave: These two caves (about 500 feet apart) contain about 20-25 hibernating Townsend's big-eared bats. The caves are not heavily visited. There mav be other caves and bats in this flow as it has not been intensively searched for caves. This population may be a segment of the Quartz Mountain group, about eight to 10 air miles to the south. No bats were noted in the summer visit. The best protection for the bats at the present time is to not make cave locations available to the public. Lava River Cave: I only noted five Townsend's big-eared bats here, and wondered which subpopulation they belong to. The number is similar to that noted previously, so present visitation is probably not detrimental. Although the road into the park is gated, the cave gets visitors as late as November (C. Larson, pers. comm.). It would be interesting to determine the numbers of winter visitors. Winter closure should continue. Summer searches of both ends of the cave revealed no day roosting bats, but the cave is a major night roost and feeding area for a small nursery of long-eared bats (M. evotis) and a single hairy-winged bat (M. volans). These bats were noted feeding in the sink and throughout the park area, using the gated portion of the cave as a night roost. 4. Wallowa-Whitman National Forest Mtn. Chief Mine (Hell's Canyon): Mtn. Chief hibernaculum and the nursery roost mines for all species in Hell's Canyon should be posted inside the cave entrance to alert those who enter to the presence of Townsend's big-eared bat and the need to protect the site from disturbance. Boaters and hikers should be discouraged from winter visitation to the Mtn. Chief site and any other mines found to contain hibernating bats. Summer -36- roost site's should also be signed and protected by river patrol personnel from 1 May to 1 August. Adits used by bats should be removed from the exploitable mineral base to prevent future conflicts. Bureau of Land Management 1. Roseburg District Scott Mountain Cave: This is a hibernaculum for at least 50 Townsend's big-eared bats and long-eared bats. Excessive disturbance should be avoided during the winter months (November-April) to prevent drastic population declines. Monitoring of this site is recommended. 2. Prineville District Paulina Cave: Prineville BLM should attempt to dig open and stabilize the entrance to this historically large hibernaculum to determine if the local population is greater than the single bat which I found. If Townsend's big-eared bats return to the cave, a management plan for the winter population should bff developed. In addition, signs indicating "cave" and "Cave Gulch" should be removed as the entrance to this cave is extremely unstable and dangerous. Townsend's big-eared bats were observed flying on 12 July. It is probable that there is still a small but stable population in the vicinity. A thorough search of rimrock and uninhabited buildings within a five-mile radius should be undertaken to determine if a summer colony still exists within this area. Any such site discovered should be managed to minimize human impact. Charcoal 2 and Pictograph Caves (Arnold Cave System): Pictograph Cave contains a significant number of hibernating bats. Unfortunately the hibernating bats were mostly in the low ceiling end of Pictograph Cave where they were extremely -37- vulnerable to disturbance. Both caves are used as summer night roosts and have an occasional day roosting bat, but no important summer concentrations. Perhaps a post-hunting season- closure of the roads in this area with the U.S. Forest Service would afford some protection to the bats. Signs posted inside the caves may also be helpful. This portion of the Arnold Cave System needs biannual monitoring. 3. Lakeview District Derrick, Hidden, Tree, and Hairpen Caves: The four to five caves in the Derrick Cave area contain a few bats both summer and winter. Only two Townsend's big-eared bats were found hibernating here, but Tree and Hairpin Caves were very warm and likely serve as summer night roosts for some local bats. Summer searches revealed only one Townsend's big-eared bat in Hairpin Cave. Lily Cave needs to be revisited in the winter. I could not find the obscure opening until early in July 1986, and the presence of guano indicates late fall or winter use. Public use of these caves is heavy and an effective method of public education is needed. Fires, garbage, and other forms of vandalism are evident at Derrick Cave. 4. Burns District Roaring Springs Cave: An agreement with Roaring Springs Ranch to limit public access to the cave above the ranch would be desirable. This local bat population is small and tenuous at best. The lack of knowledge of the location of the hibernacula will hamper this population in recovery. I have several leads pointing to a cave on Jenkin's Ranch, but it needs vertical gear to enter, and is said to be most easily noted by helicopter. -38- 5. Vale District Saddle Butte Cave System: The Saddle Butte Cave System should be given ACEC status to protect Townsend's big-eared bat and its roosts. Winter visitation to the caves, except for population monitoring (no more than once per year) should be prohibited or discouraged. Recommended closure dates are from I November to I May. Locations of the nursery sites should not be disseminated in any way to the public. I also recommend that signs with positive messages, asking the public not to enter the cave during hibernation to preserve the habitat and bats, be posted inside Coyote Trap, Tire Tube, Owyhee River, and Rattlesnake II caves. Private/State/other 1. Lane County Blue River Cave: A hibernaculum for about 20 Townsend's big-eared bats occurs in the Blue River City Park and needs protection from public intrusion during winter months. Monitoring is recommended. 2. Crook County Opal Springs Cave: A cave north of Opal Springs and just above the state gauging station in the Crooked River Gorge, contained three to nine inches of guano-over its entire floor. The cave profile is such that it traps warm air rising from the talus pile below. A nursery colony of 800 little brown bats exists here. The bats should be protected from disturbance during the months of May, June, July, and August. _39- 3. Deschutes County Redmond Cave: Only one hibernating Townsend's big-eared bat was found here; it may be a part of a local population. This lava flow is a long distance from the Horse and Arnold systems. Summer searches revealed only one bat. using the cave as a night roost. These Caves which once held "many" bats (according to at least two local people) may now attract only "wanderers" due to the types of human use they receive (i.e., fires and parties). The area should be protected between 1 November and I April. Stookey Ranch Cave: Presently owned by the Sundance Corporation, its above ground areas are jointly managed with BLM for winter wildlife range. Portions of this cave are extremely dangerous and not for the novice. Fortunately it is seldom visited and not highly visible. It is the most . I mportant hibernaculum known in central Oregon. Most bats were using the lower level, accessible only by a frame ladder via a very unstable pit. During winter months, this cave protects over 60% of Townsend's big-eared bats in central Oregon. During summer, I noted about four to five Townsend's big-eared bats and two Myotis sp. using the upper levels (entry area) as a night roost. While surveying the lower level for day roosting bats, I discovered an upper "wet" passage about 700 feet in length that had a lot of visible bat guano. This passage may serve as a Myotis hibernaculum, as air movement does not seem to be as noticeable as in the lower level. This may be the most important central Oregon site, if sites are prioritized. Unfortunately, the cave's only protection currently is its difficult access and relative anonymity. Acquisition or management agreements are needed immediately; perhaps a cooperative agreement with The Nature Conservancy, Bureau of Land Management, and Oregon Department of Fish and Wildlife. -40- Stove and Barlow Caves: The two hibernating Townsend's big-eared bats and the nursery colony found in these caves may be from the Arnold System about 10 miles to the south. The inaccessibility of three of the major caves (Wilson, Lewis, and Johnson Farm Caves) suggests possibilities for additional bats of this and other species. A single male bat was found in Young's Cave during the summer. This cave is now gated to limit public access. More bats may begin to use this cave as disturbance is limited. It is likely that the Horse System historically supported as many bats as the Arnold System does currently. Excessive human use has most likely extirpated all but the remaining 50 or so bats noted in Barlow Cave. An agreement is needed with the owner's of the Barlow Cave property to provide posting to prevent spelunkers from summer entry. 4. Grant County Officer's Cave: Now under a lease option, the Oregon Department of Fish and Wildlife should consider purchase to adequately protect this important hibernaculum. A management agreement could be entered, perhaps through The Nature Conservancy, rather than outright purchase. The primary concern is to limit access. Four mummified bats were noted among the 134 bats found during this study. All four had apparently been killed with a hammer, as all had a round indentation the size of a peen in their back. I could not get accurate counts, but earlier estimates (1970-73) of wintering bat populations numbered in the 300-600 range. It is likely that increased visitation has contributed to the population decline at this site. 5. Wheeler County Service Creek: The Townsend's big-eared bat colony was using the new cement bridge over the John Day River just to the south -41- of the junction with Service Creek. The colony apparently day roost s in the enclosed bottom of the bridge where openings were provided for sewer and water pipes. The species fo-rages extensively on the north end of the bridge. The south end of the bridge is used by a pallid bat (Antrozous pallidus) nursery colony as a night roost. The Townsend's big-eared bats here may be from Officer's Cave to the east, as I found no other evidence as to where either colony might be the remainder of the year. An endangered species throughout much of its eastern range, and considered by some to be "nowhere abundant" (Barbour and Davis 1969), Townsend's big-eared bat faces a similar fate in Oregon without adequate protection of the critical hibernacula and nursery colonies defined in this study. A commitment is needed from federal and state land management agencies to monitor and protect vulnerable populations of this species, as well as a concerted effort to educate the public in the role they must play in safe-guarding bat habitat. ACKNOWLEDGEMENTS I would like to thank the following for their personal and departmental support throughout this study; each played a rale unique to their position and each proved invaluable. Oregon Department of Fish and Wildlife: Chris Carey, Carrie Carragher, Jim Collins, Ken Durbin, Jean French, Bill Haight, Mark Henjum, Jim Lemos, Joe Pesek, Frank Newton, Greg Robarts, De! Sanford, and Harlan Scott; Bureau of Land Management: Walt Devaurs, Wayne Elmore, Bob Kindschy, Matt Kniesel, Bill Neitro, Jon Sadowski, and Guy Sheeter.- U.S. Foest Service: Bernie Altenbach, Ralph Anderson, Roger Baker, Hugh Black, Debbie Boyd, Norm Close, Bill Dugas, Alan Dyck, Barb Fontaine, Brent Frazier, Jesse Gonzales, Ed Harshman, Kirk Horn, Jay Jesse, Kathy Johnson, Barbara Manning, Rod Miller, Theresa Nichols, Lisa Norris, Richard Pederson, Charles Philips, Bob Phillips, John Phipps, Carlos Pintos, Art Seamons, and Ed Styskel; Old-growth Committee: Len Ruggeria and Andy Cary; and Portland State University: Richard Forbes. -42- In addition, I would like to acknowledge the assistance of Charlie Larson (National Speleological Society), Jerry Thorton (American Cave Conservation Association), The Oregon Grotto, Portland Audubon Society, Portland Parks Bureau, all property owners who allowed access to potential bat habitat, and all members of the general public who responded to requests for information on '@@ s4g"@4I UaL 1161119z.--- Special thanks are due the many volunteers who helped with field work, public relations and technical support including: Rick Attig, John Barss, Tanya Barfield, Brad Baughman, Joshua Peterson, Michael Clapp, and Thomas Dolman. I would particularly like to thank my wife Nancy who endured many lonely nights for the cause and my son Andrew for his help in the field. The study was conducted under contract to the Oregon Department of Fish and Wildlife through the Nongame Wildlife Program. Additional funding for portions of the study on federally administered lands was provided by the Bureau of Land Management, the U.S. Forest Service, and the American Cave Conservation Association. REFERENCES Bailey, V. 1936. The mammals and life zones of Oregon. N. Amer. Fauna #55, 416 pp. Barbour, R.W., and W.H. Davis. 1969. The bats of America. Univ. Press of Kentucky. 268 pp. Bonaccorso, F.J., and N. Smythe. 1972. Punchmarking bats: an alternative to banding. J. Mammal. 53:389-390. Bonaccorso, F.J., N. Smythe, and S.R. Humphrey. 1976. Improved techniques for marking bats. J. Mammal.. 57:181-182. Booth, E.S. 1945. Corynorhinus in northeastern Oregon. Murrelet 26:26. Cressman, L.S., and C.A. Reed, Jr. 1938. Two new Oregon localities for two races of pale bats. J. Mammal. 19.-248-249. -43- (1976) A and Cross, S.P. Ed. . survey of bat populations their habitat preferences in southern Oregon. A student originated studies project funded by the National Science Foundation through Southern Oregon State College. 89pp., unpubl. Hall, E.R. 1981. The mammals of North America, 2nd Edit. Vol 1, 600 pp. Maser, C., and S.P. Cross. 1981. Notes on the distribution of Oregon bats. Res. Note, PNW=31701. 31 pp. U.S. Fish and Wildlife Service. 1985. Federal Register. 50(181):37958-37967. -44- I @t a L m I C-) rm APPENDIX A Sources Used to Determine Potential Bat Hibernacula in Central Oregon TITLEMAME Oregon Metal Mines Handbook - Vol 14 An Introduction to the Caves of the Bend Area Speleograph (Oregon caver newsletter) WVG Rag (Oregon caver newsletter) Charlie-Larson - Personal files -46- APPENDIX B Museums Visited or Contacted for Additional Bat Records MUSEUM LOCATION Blue Mtn. Community College (BMCC) Pendleton, OR Boise State University (BSU) Boise, ID Eastern Oregon State College (EOSC) LaGrande, OR Idaho State University (ISU) Pocatello, ID Malheur Environmental Field Station (MEFS) Harney County, OR Museum of Natural History (SDMNH) San Diego, CA Portland State University (PSU) Portland, OR University of California (UCB) Berkeley, CA University of Michigan (UMNZ) Michigan University of Oregon (UO) Eugene, OR University of Washington (UW) Seattle, WA Walla Walla College (WWC) College Place, WA Washington State University (WSU) Pullman, WA Whitman College Walla Walla, WA -47- APPENDIX C Habitat Types and Definitions Used For Mist Net Inventories Northwest Oregon (1982) I divided vegetative types into: open agriculture; urban; riparian; Hardwood; old-growth conifers (all sampled were of the Douglas fir-western hemlock complex); mature conifers (15 to 20 inch dbh); and clearcuts and regenerated stands (less than 50 years old). Western Oregon (1983) 1. Old-growth Douglas fir (Pseudottsuga menzeisii) - age approximately 200+ years and bole size 36+ inch dbh; this was subdivided into two types, mesic (western hemlock occurs) and xeric (pine species are mixed in); 2. Mature Douglas fir (50-100 years, bole size 12 to 24 inches); 3. Marketable Douglas fir (50-100 years, bole size 12 to 24 inches); 4. Reprod. Douglas fir (0-50 years, bole size less than 12 inches); 5. Hardwood stands - alder, oak, big-leaf maple, and madrone; 6. Riparian zones - alder/douglas fir, maple/alder, and alder/oak; and 7. True fir complex at higher elevations. Central Oregon'(1986) OG = Old-growth; PP Pins,7onl,rs conj; OF = Pseudotsuga menzeisii TF Mixture of Abies sp MC xed ifer species; RP riparian zone; SS shrub steppe; and LP = lodgepole pine. Eastern Oregon (1985) Habitat Sites Sampled 1. Caves (C) 2. Mines (M) 5 3. Rimrock (RR) 14 4. Shrub Steppe (SS) 27 5. Juniper (J) 2 6. Ponderosa Pine (PP) 31 7. Coniferous Transition Zones (CT) 6 -48- APPENDIX C (continued) Eastern Oregon (1985) (continued) Habitat Site Sampled 8. True Fir Complex (TF) 6 9. Riparian Zones (RP) 2 SS was dominated by the presence of low or high sage (Artemesia tridentata, A. arbuscula) and introduced bunch grasses (ALj@rr on sp J had @J5`niper 7urripeirus oCci 6 entalis) as the dominant overstory with A. tridentata and as understory. PP usually consisted of ponderosa pine Pinus as the dominant overstory with J. occidentalis and A. tr en ociated species. The CT zone cc7nsi-st-e-d-o-T -conifers Tj. To-@]-er?sa, Abies sp. and Pseudotsuqa menziesii), with dominant species determined by e7evation a-n-d-sT-ope dir7e@ction. YF habitat was dominated by Abies sp. with marignal populations of P. menziesii scattered throughout the l-owest elevations. RP consisted of Salix `s7p.-and Populus tremuloides at higher elevations and Salix sp and P-.trico7carta at the lower elevations. I considered an area RP when the ass6c'-iated P an species represented about 20% of a one mile radius within the sample site. -49- APPENDIX D Availability of Maps for Caves Containing Bat Roosts, Hibernacula and Nursery Colonies Information on the availability of maps of cave interiors can be obtained by contacting Mark Perkins, 5130 SW Idaho Street, Portland, OR 97221. (503)244-6613. -50-