Colorado Bat Conservation Plan

Home , Ia (genus), South American hoary bat

COLORADO BAT CONSERVATION PLAN

SECOND EDITION

Prepared by: The Colorado Bat Working Group The Colorado Committee of the Western Bat Working Group

By K.W. Navo, D.J. Neubaum, and M.A. Neubaum (Editors) March 2018

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Suggested Citation: Navo, K.W., D. N. Neubaum, and M.A. Neubaum, eds., 2018. Colorado bat conservation plan. Second Edition. Colorado Committee of the Western Bat Working Group.

Available at the Colorado Bat Working Group webpage (http://cnhp.colostate.edu/cbwg/consPlan.asp).

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Table of Contents

ACKNOWLEDGMENTS ...... V INTRODUCTION ...... 1 CONSERVATION STRATEGY ...... 7 I. MINING IMPACTS ...... 8 INADEQUATE KNOWLEDGE OF BAT DEPENDENCE ON MINES ...... 11 RENEWED AND ACTIVE MINING PRACTICES ...... 12 CLOSURE OF ABANDONED/INACTIVE MINES ...... 13 II. CAVE MANAGEMENT PRACTICES ...... 17 INADEQUATE KNOWLEDGE OF BAT DEPENDENCE ON CAVE HABITAT ...... 21 SURFACE AND SUBSURFACE LAND MANAGEMENT PRACTICES ...... 22 MANAGING RECREATION IMPACTS ...... 25 INTENTIONAL DISTURBANCE AND VANDALISM ...... 28 III. ROCK CREVICE MANAGEMENT PRACTICES ...... 33 INADEQUATE KNOWLEDGE OF BAT DEPENDENCE ON ROCK CREVICE HABITAT...... 36 SURFACE AND SUBSURFACE MANAGEMENT PRACTICES ...... 37 MANAGING RECREATION IMPACTS ...... 39 INTENTIONAL DISTURBANCE AND VANDALISM ...... 41 IV. FOREST AND WOODLAND MANAGEMENT PRACTICES ...... 45 FOREST AND WOODLAND MANAGEMENT ACTIONS IN COLORADO ...... 50 INSECT OUTBREAKS, TREE DISEASES, AND WILDFIRE ...... 52 FUEL REDUCTION, RANGELAND IMPROVEMENT, AND ECOSYSTEM RESTORATION ...... 54 V. RANGELAND MANAGEMENT PRACTICES ...... 58 LOSS AND DEGRADATION OF RIPARIAN HABITAT ...... 59 LOSS OF VEGETATIVE STRUCTURE IN PINYON-JUNIPER AND SAGEBRUSH RANGELANDS ...... 61 IMPACTS FROM PESTICIDE SPRAYING ...... 62 CONSERVATION AND MANAGEMENT OF DRINKING WATER SOURCES ...... 63 VI. URBAN DEVELOPMENT ...... 70 URBAN HABITAT ...... 71 URBAN ROOSTING ECOLOGY OF ANTHROPOGENIC STRUCTURES ...... 72 URBAN FORAGING ...... 74 POLLUTION ...... 76 DISEASE RISK ...... 77 VII. BATS AND DISEASE ...... 81 MONITORING OF WNS IN COLORADO ...... 85 INADEQUATE KNOWLEDGE OF BATS AND DISEASE IN COLORADO ...... 85 VIII. ENERGY DEVELOPMENT...... 88 WIND ENERGY POTENTIAL AND TECHNOLOGY ...... 88 OIL AND GAS POTENTIAL AND TECHNOLOGY ...... 91 SOLAR POTENTIAL AND TECHNOLOGY ...... 98 IX. GUIDANCE FOR SCIENTIFIC ACTIVITIES ...... 106

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RESEARCH, INVENTORY AND MONITORING ...... 106 TRAPPING AND HANDLING ...... 107 MARKING ...... 108 TELEMETRY ...... 109 X. CONSIDERATIONS FOR BAT ROOST PROTECTION ...... 111 BAT-COMPATIBLE GATES ...... 112 BUFFER ZONES ...... 113 SEASONAL CLOSURES ...... 113 EXCLUSIONS ...... 114 XI. SPECIES STATUS, POPULATION TRENDS, AND MONITORING ...... 116 DISEASE ...... 116 CAVES AND MINES ...... 117 ROOSTS ...... 117 SPECIES STATUS ...... 118 ENERGY ...... 119 MIGRATION ...... 119 XII. ASSESSING THREATS TO BAT SPECIES: THE COLORADO BAT MATRIX ...... 122 CBWG DEFINITIONS ...... 122 XIII. SPECIES ACCOUNTS ...... 126 ALLEN’S BIG-EARED BAT (IDIONYCTERIS PHYLLOTIS)...... 127 BIG BROWN BAT (EPTESICUS FUSCUS) ...... 130 BIG FREE-TAILED BAT (NYCTINOMOPS MACROTIS) ...... 134 BRAZILIAN FREE-TAILED BAT (TADARIDA BRASILIENSIS ) ...... 137 CALIFORNIA MYOTIS (MYOTIS CALIFORNICUS) ...... 140 CANYON BAT (PARASTRELLUS HERPERUS) ...... 143 EASTERN RED BAT (LASIURUS BOREALIS) ...... 146 FRINGED MYOTIS (MYOTIS THYSANODES) ...... 149 HOARY BAT (LASIURUS CINEREUS) ...... 152 LITTLE BROWN MYOTIS (MYOTIS LUCIFUGUS) ...... 156 LONG-EARED MYOTIS (MYOTIS EVOTIS) ...... 162 LONG-LEGGED MYOTIS (MYOTIS VOLANS) ...... 166 PALLID BAT (ANTROZOUS PALLIDUS) ...... 170 SILVER-HAIRED BAT (LASIONYCTERIS NOCTIVAGANS) ...... 174 SPOTTED BAT (EUDERMA MACULATUM) ...... 178 TRI-COLORED BAT (PERIMYOTIS SUBFLAVUS)...... 183 TOWNSEND’S BIG-EARED BAT (CORYNORHINUS TOWNSENDII) ...... 187 WESTERN SMALL-FOOTED MYOTIS (MYOTIS CILIOLABRUM) ...... 191 YUMA MYOTIS (MYOTIS YUMANENSIS) ...... 195

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ACKNOWLEDGMENTS

We thank the board of the Colorado Bat Working Group for their time and effort on the revision of this plan - Mikele Painter, Rob Schorr, Roger Rodriguez, Amy Englert, Melissa Siders, Michael Dixon, Michael Schirmacher, Daniel Neubaum, and Kirk Navo. The original bat conservation plan was written in 2004 by Laura E. Ellison, Mike B. Wunder, Cheri A. Jones, Cyndi Mosch, Kirk W. Navo, Kathy Peckham, John E. Burghardt, Julie Annear, Ron West, Jeremy Siemers, Rick A. Adams, and Erik Brekke. We would like to acknowledge Mark Hayes for developing the disease chapter, and Tina Jackson and Mikele Painter for providing extensive reviews on various drafts of this conservation plan. We would also like to thank the following people for reviewing and commenting on various drafts of this plan: Lea Bonewell, Kevin Castle, Paul Cryan, Michael Dixon, Amy Englert, Randy Ghormley, Jennifer House, Will Keeley, Kristen Philbrook, Antoinette Piaggio, Roger Rodriguez, Michael Schirmacher, Rob Schorr, Missy Siders, Jeremy Siemers, and Apple Snider. Comments on energy development in Colorado were provided by Michael Warren and Karen Voltura of Colorado Parks and Wildlife. Kellen Keisling provided assistance with formatting the species accounts. Derek Bristol and Kevin Manley of Colorado Cave Survey provided cave gate information. Western State Students Dylan Gomes, Katelynn Russell, Cassandra Mendoza, and William Turner provided initial help with compiling species accounts. Cover art is by Lucas Navo.

Maternity colony of big brown bats in a rock crevice. Photo by D. Neubaum.

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INTRODUCTION

Nineteen of the 124 or more species of mammals inhabiting Colorado are bats. The unique life history characteristics of bats prevent many people from realizing that they comprise 15 percent of our native mammal fauna. Being fast fliers that are active at night, bats are mostly elusive to human detection except in the early evening hours when they can be seen foraging, or when they are observed in their roosting habitat. In addition, bats often roost in hard-to-reach, well-hidden places making human encounters with them rare. Threats to bats in Colorado and worldwide have lead to multiple mortality events (O’Shea et al. 2016). Coupled with roosting and foraging habitat loss, these threats create the potential for declines in bat populations. Since the first edition of the Colorado Bat Conservation Plan in 2004, several new threats to bats have surfaced, and are addressed in this 2017 revision. Chief among these threats is the emergence of White- nose Syndrome, an infectious disease caused by in an infectious fungus, Pseudogymnoascus destructans, which has killed millions of bats in eastern North America, and continues to make westward progression across the continent. Energy development has also become an elevated concern for many bat species, specifically wind and solar energy. Impacts from development of these energy resources to bats has the potential to increase exponentially as the country works towards advancing renewable energy methods and addressing the threats of climate change. Implementation of thoughtful conservation measures for bats will be needed to avert population declines, potential species listings, or worse, extinction events for these unique Pallid bat. Photo by K. Navo mammals.

Most bats found in Colorado are relatively small, but wingspans of Colorado’s largest resident bat species, the big free-tailed bat (Nyctinomops macrotis), can reach 44 cm (16 in). The smallest bat species is the canyon bat (Perastrellus hesperus, 4-6 g), and the heaviest is the hoary bat (Lasiurus cinereus, up to 35 g). Bats are extraordinarily long-lived for their body size. For example, the little brown myotis (Myotis lucifugus) is capable of living more than 30 years in the wild (Cross 1976). Populations replace themselves rather slowly; in almost all species, females typically give birth to a single young per year. Although juvenile survival is high in the roost, once the young bats fly, mortality can be extremely high

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(Humphrey and Cope 1976). Because many bat species in Colorado form concentrated colonies, give birth to only one young per year, and have the potential for high juvenile mortality, they are especially prone to threats from human encroachment, loss of habitat, and disturbance to roosts. They also spend more than half their lives in their roosting environment and, as such, are highly sensitive to disturbance and loss of roosting habitat, especially during reproductive and hibernation seasons. Bats in Colorado utilize a variety of roosts including caves, rock crevices, trees, and human-made structures such as mines, tunnels, bridges, and buildings.

For most species of Colorado bats, males and females segregate during the active summer months (Neubaum et al. 2006). Males form small bachelor colonies or roost singly, whereas females form larger colonies that range from a few individuals to as many as several thousand females and their young (Armstrong et al. 1994; Neubaum pers. comm.). Fall swarming involves high levels of bat activity throughout the night, with bats flying in and out of caves or mines. The reasons bats use caves or mines for swarming are not fully understood but the behavior could serve multiple social purposes, including mating and orientation of young bats for migration or with potential hibernacula (Veith et al. 2004), and the activity has been documented in Colorado (Navo et al. 2002; Englert 2008). The potential importance of swarming to the viability of bat species is largely unknown, but could be critical if, for example, it is shown to affect survival, reproduction, or the spread of diseases. Colorado bat species mostly hibernate locally, undergoing short seasonal migrations that may require moving to a higher elevation in order to find suitable winter roosts (Neubaum et al. 2006). Abandoned mines and caves are used as hibernacula by some species, particularly Townsend’s big-eared bats (Corynorhinus townsendii; Ingersoll et al. 2010; Hayes et al. 2011). Rock crevices and talus are thought to be used as hibernacula as well (Neubaum et al. 2006).

Throughout history, bats have been misunderstood and vilified. This negative outlook stems from the lack of knowledge of a mammal that in many ways tests our sense of reality. The more we learn about their true biology, however, the less scary and more astonishing bats become. Conservation efforts for bats lag far behind those for more charismatic animals. Technological advances, such as the development of high frequency-scanning and recording devices (bat detectors) that have enhanced acoustic methodology, radio telemetry, pit tagging, and the use of satellites and global positioning systems, have allowed biologists to better understand the diversity, behavior, and ecology of bats.

In Colorado, efforts to promote bat conservation and increase public education have led to the protection of bat colonies, and are slowly changing the fear and hatred of bats into fascination and appreciation. Education, along with public support for conservation efforts, is essential in conserving bat populations and their roosting habitats, and thus maintaining their ecological role as the most significant vertebrates preying on nocturnal insects in Colorado and throughout North America. In an effort to establish needs and goals of bat conservation, the Colorado Committee of the Western Bat Working Group was established in 1998 (see Colorado’s link on the Western Bat Working Groups website at http://wbwg.org/). Its mission is to provide guidance to private individuals, agencies, and other groups

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Figure 1. Ecological distribution of bats in Colorado in 4 ecoregions and 14 community-types (see Table 1), based on Armstrong (1972). to facilitate the conservation and management of bats and their habitats in Colorado. Bat conservation needs to be proactive in order to prevent sensitive species from becoming endangered or threatened. The Colorado Bat Conservation Plan revision summarizes the current state of knowledge of bats, continues to prioritize species-specific needs, identifies threats to bats in Colorado, provides goals for species conservation, and lists management recommendations and research needs to meet those goals. The Colorado Bat Working Group has also developed the Colorado Bat Matrix to identify and rank threats to bats in our state, which replaces the Species Ranking section found in the first edition of this plan (Ellison et al. 2004). This conservation plan is intended for dissemination to land management agencies in Colorado, those with an interest in bat conservation and research, and institutions responsible for managing natural resources in the state.

The Conservation Plan is structured to follow ecoregions found in Colorado. We provide a list of bat species found by ecoregion across the state (Figure 1.1, Table 1.1). Conservation Strategies focus on eight categories or activities generally tied to these ecoregions with each encompassing multiple issues important to bat populations in Colorado: (1) mining; (2) cave management (3) crevice management; (4) forest management; (5) rangeland management; (6) urban development; (7) diseases of bats; (8) energy

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development. Additionally, guidance for scientific activities, considerations for bat roost protections are provided. Species status, population trends, and monitoring are discussed and an introduction to the Colorado Bat Matrix included helping managers address bat conservation issues. Finally, Colorado bat species account overviews are provided in the plan tailored towards knowledge gained from efforts conducted within the state whenever possible. Bats mark the presence of healthy, functioning ecological communities. We hope that the gaps in knowledge outlined in this document continue to provide direction for future bat research projects and management planning in the state of Colorado.

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Table 1. List of 19 species of bats known to occur in Colorado and the community-types* in which they occur (see Figure 1), based on Armstrong (1972). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Allen’s lappet-browed bat X X X (Idionycteris phyllotis) Big brown bat X X X X X X X X (Eptesicus fuscus) Big free-tailed bat X X (Nyctinomops macrotis) Brazilian free-tailed bat X X (Tadarida brasiliensis) California myotis X X X (Myotis californicus) Canyon bat X X X X (Parastrellus hesperus) Eastern red bat X (Lasiurus borealis) Fringed myotis X X (Myotis thysanodes) Hoary bat X X X X X X X (Lasiurus cinereus) Little brown myotis X X X X X X X X (Myotis lucifugus) Long-eared myotis X X X X X X X X (Myotis evotis) Long-legged myotis X X X X X X X (Myotis volans) Pallid bat X X X X (Antrozous pallidus) Silver-haired bat X X X X X X X (Lasionycteris noctivagans) Spotted bat X X X (Euderma maculatum) Townsend’s big-eared bat X X X X X (Corynorhinus townsendii) Tri-colored bat X (Perimyotis subflavus) Western small-footed myotis X X X X X X X (Myotis ciliolabrum) Yuma myotis X X X (Myotis yumanensis) TOTALS 1 1 8 8 8 9 15 10 5 6 4 3 6 1 *1 = Subhumid grassland; 2 = Plains wetland; 3 = Plains riparian woodland; 4 = Saxicoline brush; 5 = Sagebrush; 6 = Semidesert scrub; 7 = Pinyon-juniper woodland; 8 = Ponderosa pine woodland; 9 = Montane forest; 10 = Mountain meadow; 11 = Subalpine forest; 12 = Highland streambank; 13 = Aspen woodland; 14 = Alpine tundra/fellfield

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LITERATURE CITED Armstrong, D. M. 1972. Distribution of Mammals in Colorado. Monograph of the Museum of Natural History, The University of Kansas 3:1-415. Armstrong, D. M., R. A. Adams, and J. Freeman. 1994. Distribution and ecology of bats of Colorado. University of Colorado Museum, Boulder, CO. Cross, S. P. 1976. A survey of bat populations and their habitat preferences in southern Oregon. Report to National Science Foundation, Southern Oregon State College, Ashland. Englert, A. C. 2008. Chemical recognition and swarming behavior in bats. M.S. thesis, University of Colorado, Denver. Denver, CO. Hayes, M. A., R. A. Schorr, and K. W. Navo. 2011. Hibernacula Selection by Townsend’s Big-Eared Bat in Southwestern Colorado. Journal of Wildife Management 75:137-143. Humphrey, S. R., and J. B. Cope. 1976. Population ecology of the little brown bat, Myotis lucifugus, in Indiana and north-central Kentucky. Special Publications, American Society of Mammalogists 4:1- 81. Ingersoll, T. E., K. W. Navo, and P. De Valpine. 2010. Microclimate preferences during swarming and hibernation in the Townsend's big-eared bat, Corynorhinus townsendii. Journal of Mammalogy 91:1242-1250. Navo, K. W., S. G. Henry, and T. E. Ingersoll. 2002. Observations of swarming by bats and band recoveries in Colorado. Western North American Naturalist 62:124-126. Neubaum, D. J., T. J. O'Shea, and K. R. Wilson. 2006. Autumn migration and selection of rock crevices as hibernacula by big brown bats in Colorado. Journal of Mammalogy 87:470-479. O'Shea, T. J., P. M. Cryan, D. T. S. Hayman, R. K. Plowright, and D. G. Streicker. 2016. Multiple mortality events in bats: a global review. Mammal Review 46(3), 175-190. Veith, M., N. Beer, A. Kiefer, J. Johannesen, and A. Seitz. 2004. The role of swarming sites for maintaining gene flow in the brown long-eared bat (Plecotus auritus). Heredity 93:342-349.

Pallid bat. Photo by D. Neubaum.

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CONSERVATION STRATEGY

The Conservation Strategy is designed to provide natural resource managers, researchers, and graduate students with information and direction in the conservation needs of Colorado bats. The Strategy provides an overview of the most important issues identified for each species and for bats in general. The categories below include threats that either directly or indirectly impact the species or the habitats they depend on for survival, and methods and techniques typically used in bat related conservation studies. Once a category was identified, we then selected key issues, goals for each issue, objectives for each goal, and management and research needs to accomplish each objective. The major categories we identified are:  Mining Impacts  Cave Management Practices  Rock Crevice Management Practices  Forest and Woodland Management Practices  Rangeland Management Practices  Urban Development  Bats and Disease  Energy Development  Guidance for Scientific Activities  Considerations for Bat Roost Protection  Species Status, Population Trends, and Monitoring  Assessing Threats to Bat Species: The Colorado Bat Matrix  Species Accounts The conservation strategy is not intended to be a benchmark for what types of projects should be supported in the state. Nor is it a justification for not funding or supporting other types of research not specifically mentioned. Rather, it should provide assistance to resource managers and researchers given the limited funding and growing conservation needs for many species.

Long-eared myotis. Photo by D. Neubaum.

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I. MINING IMPACTS

By Kirk W. Navo

Twenty-eight (62%) of the 45 bat species in the U.S. use mines (Altenbach and Pierson 1995). Bats have become dependent upon abandoned mines for roosting habitat where recreational caving and deforestation have diminished natural bat habitat (Tuttle and Taylor 1994; Altenbach and Pierson 1995). Colorado has an estimated 23,000 inactive mines and survey results indicate that about 50% of abandoned mines show signs of bat roosting habitat, and approximately 18% are characterized as important sites of bat activity (K. Navo, unpublished data). The abandoned mined lands (AML) Ladder gate on mine. Photo by K. Navo. program has led many agencies to inventory mine locations. For instance the National Park Service (NPS) has identified 3,200 mine sites in the national park system, with 10,000 individual mine openings (Burghardt 2003). Like cave roosts, mines are used as hibernacula, maternity roosts, bachelor colonies, transitional roosts, migratory stopovers, night roosts, or drinking sites. Yet unlike caves, abandoned mines are being systematically closed for public safety. This activity can pose a threat to bats that use mines, and mine closure methods can be destructive to bat roosts if done at an improper time

Full gate on mine. Photo by K. Navo. (Altenbach and Pierson 1995). However, gates that keep out humans but allow access by bats have been used extensively in the eastern US for over 40 years. To preserve critical habitat, bat gates must be designed to allow unrestricted ingress and egress, especially for maternity roosts. The bat gate closure must also minimize changes to the microclimate of the roost (Tuttle 1977; White and Seginak 1987; Richter et al. 1993).

Since 1980, government agencies, conservation groups, and private individuals have safeguarded over 6,120 abandoned mines in Colorado and many thousands more in the US. In 1990 the Colorado Division of Wildlife (now Colorado Parks and Wildlife; CPW) and the Colorado Division of Minerals and Geology (now Division of Reclamation, Mining, and Safety; DRMS) began a cooperative effort — the Bats/Inactive Mines Project — to survey all abandoned mine openings for bat use prior to closure, and to install bat gates on those openings that provide critical habitat. In 2013, a trend towards moving Culvert ladder gate. Photo by K. Navo.

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away from bat surveys at mines in AML programs was initiated, and replaced with an approach to gate all mines with potential for providing bat habitat. As of 2013, DRMS, CPW, Bureau of Land Management (BLM), and U.S. Forest Service (USFS) have installed more than 850 bat-compatible closures on inactive mines. Some mines have multiple openings and require more than one gate. While more research is needed on species-specific responses to particular cave/mine gate designs, results of over 20 years of post-gate evaluations indicate several designs are working well (Navo and Krabacher 2005).

Mines are used as habitat by 14 Colorado bat species, including some identified in CPW’s State Wildlife Action Plan (SWAP) as Tier 1 Species of Greatest Conservation Need (Townsend’s big-eared bat; Corynorhinus townsendii), little brown bat (Myotis lucifugus), fringed myotis (M. thysanodes), and other species, some of which were formerly designated as Category 2 candidate species under the Endangered Species Act (ESA; USFWS 1994). The following bat species are known to use mines as day roosts, maternity roosts, transition roosts or hibernacula: Townsend’s big-eared bat, California myotis (M. californicus), western small-footed myotis (M. ciliolabrum), long-eared myotis (M. evotis), little brown myotis, fringed myotis, long-legged myotis (M. volans), pallid bat (Antrozous pallidus), big brown bat (Eptesicus fuscus), and Yuma myotis (M. yumanensis). In addition, a unique bachelor colony of 100,000 to 250,000 Brazilian free-tailed bats (Tadarida brasiliensis) inhabits the Orient Mine in the San Luis Valley during the summer. This is the largest known bat colony in Colorado.

Abandoned mines are particularly important to Townsend’s big-eared bats, a Colorado Species of Special Concern, a Tier 1 Species of Greatest

Towsend’s big-eared bats exiting mine Conservation Need in the SWAP, a former category 2 through gate. Photo by D. Neubaum. candidate under the ESA (USFWS 1994), a Sensitive Species for the USFS, and a Special Status Species for the BLM. The author knows of 18 Townsend’s big-eared bat maternity roosts in Colorado, 15 of which are in abandoned mines. There are hundreds of hibernacula and/or transient roosts currently known, most of which are in abandoned mines. Most of these colonies are small in size and estimated to contain fewer than 30 individuals per mine. Identification and preservation of mines for bat habitat is critical to maintaining current populations of Townsend’s big-eared bats and other sensitive bat species. Bat gates prevent unwanted human access to dangerous mines while preserving critical bat habitat.

Another factor that could impact mine-roosting bat species in Colorado is active mining operations. Renewed mining activity at previously inactive mines can disrupt or destroy habitats. Construction of associated facilities, road development, and deforestation can potentially impact drinking and foraging

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habitat, particularly at surface mines and ore processing sites. Cyanide leach ponds that do not restrict bat access are of particular concern as they may attract bats and birds. Surveys have shown that bats are among the most numerous mammals found dead of cyanide poisoning at these water sources (Clark 1991; Clark and Hothem 1991). Currently, there are no open cyanide ponds in Colorado and there are existing policies to ensure that there is no overall net loss of critical or important wildlife habitat consistent with CPW and USFWS recommendations. Critical habitat is often excluded from a mining permit area, or poor habitat is upgraded to compensate for the loss of habitat from mining operations. In cases where “renewed mining” is occurring, current rules and regulations consider “pre-existing conditions and the degree to which the proposed plan would provide for net improvements in the protection of human health, property, or the environment (Mineral Rules And Regulations Of The Colorado Mined Land Reclamation Board For Hard Rock, Metal And Designated Mining Operations, 2 CCR 407-1, Rule 6.4.20 (18)). For cyanide ponds, active mine operations are required to net or otherwise restrict access by birds and bats to ponds that contain more than 40 ppm cyanide. Active mines are also regulated to prevent releases of acid mine drainage, from surface or groundwater, that do not meet water quality standards. In the permit application, mining companies are required to “describe measures to prevent wildlife from coming into contact with designated chemicals, toxic or acid forming chemicals, or areas with acid mine drainage (Mineral Rules And Regulations Of The Colorado Mined Land Reclamation Board For Hard Rock, Metal And Designated Mining Operations, 2 CCR 407-1, Rule 6.4.20 (18)).

Over the last 20 years, the issue of renewed mining activity at inactive mines has become a concern for bat conservation (e.g., the recent resurgence in uranium mining in the state). The rise in value of some minerals provides increased interest in mining, and inactive mines often provide locations of interest to the mining industry. Previously gated mines for bats are also being claimed and re-opened for mining activity, thus impacting existing bat colonies and removing protected habitat for some species of bats. While mining laws allow for such activities, it is important for resource managers to provide input that encourages exclusion of bats prior to renewed activity, and/or consideration of delaying initiation of mining activity until the season of bat use is past. It is also important for resource managers within AML and wildlife programs to maintain good communications during the mine permitting process, so that mines with bat gates or those known to be important bat roosts, are identified early in the process, and provide opportunities to avoid or minimize impacts to the bats utilizing such features.

A new issue for bats and mines is the emerging disease White-nose Syndrome (WNS). This disease has caused the death of millions of bats in the Eastern U.S. and Canada (USFWS 2012), and WNS has been moving westward since its discovery in 2007. This will affect issues such as surveying at abandoned mines, recreational caving and potential of human transmission of the disease, and elevate the need to monitor for the potential arrival of WNS to Colorado. See chapter VII. Bats and Disease for goals and objectives related to this issue.

Survey techniques and protocols are continually being revised to accommodate new research into bat dependence on mines. The advancement of infrared video equipment, acoustic monitoring equipment

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and techniques, and data loggers to gain insights into roost microclimate have provided more effective means of surveying and collecting important data needed in bat conservation efforts. Since mines are inherently dangerous, it is imperative that this research be conducted in a safe manner. Oxygen- deficient air, toxic gases, unstable rock, and vertical drops in and around abandoned and inactive mines have claimed 18 lives and injured 23 people in Colorado since 1955. For further discussion of potential hazards and the safety procedures to be followed at abandoned and inactive mine sites see Altenbach (1995), Burghardt (1996, 1997, 2002), Navo (2001), and Sherwin et al. (2009).

We address three categories of issues for mine-roosting bats in Colorado: inadequate knowledge of bat dependence on mines; renewed and active mining practices; and closure of abandoned/inactive mines.

INADEQUATE KNOWLEDGE OF BAT DEPENDENCE ON MINES

To conserve bat populations, it is essential to determine the importance of mines to bats. This includes determining bat dependence on mines, mine structure, configurations that provide ideal habitat, and population trends of species that utilize mines for roosts.

GOAL IDENTIFY AND DETERMINE THE IMPORTANCE OF MINES AS ROOSTING HABITAT. Objective 1: Continue to advance our knowledge on critical microclimate factors that limit bat populations inhabiting mines, particularly for species of concern, to help identify and protect roosting habitat.

Objective 2: Continue the development and evaluation of new research techniques for identification and monitoring of bat species that inhabit mines, and for the evaluation of mines as roosting habitat.

Objective 3: Research the significance of abandoned mines as roosting habitat to population viability of various species of bats, especially Townsend’s big-eared bats.

MANAGEMENT RECOMMENDATIONS  Establish or support a long term monitoring program to document population numbers and trends for species that inhabit protected mines, particularly species of concern.

RESEARCH NEEDS

 Continue the development of non-intrusive monitoring techniques and equipment for use at abandoned mines.  Continue to delineate the microclimate requirements of mine-roosting bats, and application to the issue of WNS.  Develop techniques to monitor population trends of mine-roosting bats (see also section XI. Species Status, Population Trends, and Monitoring).

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 Develop research projects to evaluate the use of non-mine/cave subterranean habitat of Townsend’s big-eared bat.

RENEWED AND ACTIVE MINING PRACTICES

Renewed mining activity at inactive mines has the potential to impact existing bat colonies, and destroy protected/gated mines as bat roosts. This type of mining activity can disrupt on-going bat conservation efforts, and cause the loss of important bat roosts. Additionally, active mining operations have the potential to impact bat populations (Brown 1997) and their habitats. The Mining Rules governing the permitting and operation of active mines are promulgated by the multidisciplinary Mined Land Reclamation Board and administered by the DRMS and other regulatory agencies. The rules prevent harm or damage to wildlife species or habitat. However, as research on bats continues, new information should be disseminated to regulatory agencies and mining operations in order to develop reclamation techniques that preserve bat populations.

GOAL PRESERVE FORAGING AND CRITICAL NON-MINE HABITATS, AND MINIMIZE IMPACTS TO EXISTING BAT COLONIES IN ACTIVE MINE AREAS. Objective 1: Provide information and technical support to mine operators and regulatory personnel about sensitive bat species, bat conservation practices, and mechanisms to preserve habitat.

Objective 2: Provide information and technical support to mine operators and regulatory personnel to monitor the success of bat conservation measures.

Objective 3: Promote proper exclusion of bats from mines that are slated for renewed mining. Encourage the delay of mining activities until the season of bat use is finished, if exclusion is not possible.

Objective 4: Work with mining companies to identify and implement new artificial bat habitats.

Objective 5: Consider options, such as formal mine withdrawals from mining claims, of significant bat roosts (See Neubaum et al. 2017) at currently inactive mines to provide long term protection and conservation.

MANAGEMENT RECOMMENDATIONS  Continue to work with mining companies and regulatory agencies to implement techniques that minimize and mitigate mine-related impacts.  Promote effective communication between land use agencies, resource managers, and mining interests to minimize impacts to bat roosts at mines under consideration for renewed mining activity.

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 Promote proper bat exclusion techniques and timing at mines with bat use prior to closures or renewed mining activities.

RESEARCH NEEDS

 Continue studies of mine design and reclamation techniques that enhance bat habitat at the conclusion of mining operations. This should include the development of viable bat roosts.  Determine the nature and extent of water quality problems and their effects on bat populations.  Determine the impact of active mining operations on bat populations.

CLOSURE OF ABANDONED/INACTIVE MINES

Closure of abandoned mines for public safety can eliminate important bat habitat. Resource managers can contact the following agencies/organizations and corresponding project managers for further information regarding AML programs and activities: CPW, Colorado Natural Heritage Program, Colorado Division of Reclamation, Mining, and Safety.

GOAL PRESERVE CRITICAL HABITAT IN ABANDONED MINES TO PROTECT VIABLE BAT POPULATIONS, ESPECIALLY SPECIES OF CONCERN. Objective 1: Promote and implement safe and effective protocols for surveying abandoned mines (e.g., Altenbach 1995; Navo 2001; Sherwin et al. 2009).

Objective 2: Survey all abandoned mine openings slated for closure to identify critical bat habitat and increase our knowledge of bat distribution, roosting ecology, and species status. This is especially important in light of the potential arrival of WNS to the state.

Objective 3: Implement WNS decontamination protocols for all surveys and reclamation activities at abandoned mines.

Objective 4: Promote and implement protocols for installing bat-compatible closures (e.g., Dalton and Dalton 1995; Tuttle and Taylor 1998; Navo and Krabacher 2002; Burghardt 2003). Evaluate any modifications to accepted bat gate designs before widespread implementation.

Objective 5: Exclude bats from mines that are slated for closure when gating is not feasible. Promote proper exclusion techniques and timing to AML programs and personnel.

Objective 6: Continue to evaluate the success of bat gates and any design modifications by monitoring mines before and after gate installation to determine post-gate usage, colony numbers and trends, and effects on mine microclimate from gate designs (Navo and Krabacher 2005).

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MANAGEMENT RECOMMENDATIONS  Work with DRMS and federal agencies to install bat-compatible closures on mines that are important bat habitat, particularly for species of concern (see Neubaum et al. 2017). Ensure that proper bat exclusion techniques are used prior to mine closures when not bat-compatible.  Promote bat surveys at mines scheduled for closures in state and federal AML programs, to ensure collection of valuable information on bat populations and WNS monitoring. Information obtained by surveys, such as species presence, microclimate data and roost types, provides important data for managers to gain support for conservation actions and species status monitoring.

RESEARCH NEEDS

 Determine the roosting habits of bats that use abandoned mines and identify the types of non- mine roosts that are used by these species. Documentation is especially important for Townsend’s big-eared bat and other species of concern, and is necessary to help determine the importance of mines as available roosting habitat (see Considerations for Bat Roost Protection).  Determine the success of bat gate designs used in Colorado, and research potential modifications to enhance their success for bat conservation and public safety (Ludlow and Gore 2000).  Determine short- and long-term potential impacts of radioactive exposure on bat populations inhabiting uranium mines, particularly species of concern, and the importance of these mines to bat populations.  Research the importance of mine clusters to local colonies and the impacts to these colonies of closing a portion of a cluster. This would include studies on the movements between nearby roosts by various species of bats.

LITERATURE CITED Altenbach, J. S. 1995. Entering mines to survey bats effectively and safely. Pp. 57-61 in Inactive Mines as Bat Habitat: Guidelines for Research, Survey, Monitoring and Mine Management in Nevada (B. R. Riddle, ed.). Proceedings. Jan. 21-22, 1994. Biological Resources Research Center, University of Nevada, Reno. Altenbach, J. S., and E. D. Pierson. 1995. The importance of mines to bats: an overview. Pp. 7-18 in Inactive Mines as Bat Habitat: Guidelines for Research, Survey, Monitoring and Mine Management in Nevada (B. R. Riddle, ed.). Biological Resources Research Center, University of Nevada, Reno. Brown, P. E. 1997. Renewed mining and reclamation: impacts on bats and potential mitigation. Pp. 196- 201 in Vision 2000 -- An Environmental Commitment: The 14th Annual National Meeting of the American Society for Surface Mining and Reclamation. Proceedings. (J. E. Brandt, ed.). Railroad Commission of Texas, Surface Mining and Reclamation Division, Austin.

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Burghardt, J. E. 1996. Effective management of radiological hazards at abandoned radioactive mine and mill sites. National Park Service, Denver, Colorado, unpublished report. (https://www.nps.gov/subjects/abandonedminerallands/upload/radpaper.pdf ) Burghardt, J. E. 1997. Safe conduct of bat surveys in abandoned underground mines. Pp. 44-45, in Natural Resource Year in Review--1997 (J. Selleck, ed.). National Park Service, Denver, Colorado. (https://www.nps.gov/subjects/abandonedminerallands/upload/safebatsurveys.pdf) Burghardt, J. E. 2002. Abandoned mine safety training course online. National Park Service, Denver, Colorado. (https://www.nps.gov/subjects/abandonedminerallands/upload/amlsafety9102003_print.pdf) Burghardt, J. E. 2003. Bat-compatible closures of abandoned underground mines in the National Park system. Arid Southwest Lands Habitat Restoration Conference, Palm Springs, California. (https://www.nps.gov/subjects/abandonedminerallands/upload/batgate9102003_screen.pdf ) Clark, D. R., Jr. 1991. Bats, cyanide, and gold mining. Bats 9:17-18. Clark, D. R., Jr., and R. L. Hothem. 1991. Mammal mortality at Arizona, California, and Nevada gold mines using cyanide extraction. California Fish and Game 77:61-69. Dalton, D. C., and V. M. Dalton. 1995. Closure methods including a recommended gate design. Pp. 130- 135, in Inactive Mines as Bat Habitat: Guidelines for Research, Survey, Monitoring and Mine Management in Nevada (B. R. Riddle, ed.). Proceedings. Jan. 21-22, 1994. Biological Resources Research Center, University of Nevada, Reno. Ludlow, M. E., and J. A. Gore. 2000. Effects of cave gate on emergence patterns of colonial bats. Wildlife Society Bulletin 28:191-196. Navo, K. W. 2001. The survey and evaluation of abandoned mines for bat roosts in the West: guidelines for resource managers. Proceedings of the Denver Museum of Nature and Science, Series 4, Number 2:1-12. Navo, K. W. and P. Krabacher. 2002. Bat Ladder Gates. In Bat Gate Design: A Technical Interactive Forum. Proceedings. March 4-6, 2002. Austin, Texas. (K. C. Vories and D. Throgmorton, eds.) Southern Illinois University, Carbondale. Navo, K.W., and P. Krabacher. 2005. The use of bat gates at abandoned mines in Colorado. Bat Research News. Vol.46: No.1. Pg 1-8. Neubaum, D. J., K. W. Navo, and J. L. Siemers. 2017. Guidelines for defining biologically important bat roosts: A case study from Colorado. Journal of Fish and Wildlife Management 8:272-282. Richter, A. R., S. R. Humphrey, J. B. Cope, and V. Brack, Jr. 1993. Modified cave entrances: thermal effect on body mass and resulting decline of endangered Indiana bats (Myotis sodalis). Conservation Biology 7:407-415. Sherwin, R. E., J. S. Altenbach, and D. L. Waldien. 2009. Managing abandoned mines for bats. Bat Conservation International, Austin, Texas.

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Tuttle, M. D. 1977. Gating as a means of protecting cave dwelling bats. Pp. 77-82 in National Cave Management Symposium. Proceedings (T. Aley and D. Rhodes, eds.). Speleobooks, Albuquerque, New Mexico. Tuttle, M. D., and D. A. R. Taylor. 1994. Bats and Mines. Bat Conservation International, Resource Publication No. 3. Tuttle, M. D., and D. A. R. Taylor. 1998. Bats and mines (revised edition). Bat Conservation International, Resource Publication No. 3. USFWS (US Fish and Wildlife Service). 1994. Endangered and threatened wildlife and plants; animal candidate review for listing as endangered or threatened species; proposed rule. Federal Register 59:58982-59028. USFWS (US Fish and Wildlife Service). 2012. North American bat death toll exceeds 5.5 million from white-nose syndrome. USFWS. (26 April 2012; https://www.fws.gov/northeast/feature_archive/Feature.cfm?id=794592078) . White, D. H., and J. T. Seginak. 1987. Cave gate designs for use in protecting endangered bats. Wildlife Society Bulletin 15:445-449.

Bats flying inside a mine. Photo J. Siemers.

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II. CAVE MANAGEMENT PRACTICES By Daniel J. Neubaum, Cyndi J. Mosch, and Jeremy L. Siemers

The use of subterranean features, such as caves, as bat roost sites is well documented. In the US, many species of bats rely on cave roosts as winter hibernacula, summer nurseries (Pierson 1998; Tuttle 2003), summer bachelor roosts, and migratory stopover sites between seasons, and for swarming activity in the fall (Parsons et al. 2003; Ingersoll et al. 2010). Swarming behavior in and around caves is an activity that is not well understood in western North America (Schowalter 1980; Navo et al. 2002), but could play an important social role for various bat species in Colorado. Consequently, caves are critical resources for bats and have been classified as “essential” for at least 18 species in the continental U.S. (McCracken 1989; Medellin et al. 2017). Caves also provide sites where unusually large aggregations of bats may occur, making the population more vulnerable to disturbance than in other settings (Sheffield et al. 1992). Threats to cave-dwelling bats include disturbances from recreational activity in and around roosts, cave development for tourism and guano mining, improper cave gate design, inappropriate or excessive scientific research (e.g., excessive banding of bats and general disturbance by researchers during critical time periods; Rabinowitz and Tuttle 1980; White and Seginak 1987; Richter et al. 1993; Tuttle 2000; O’Shea et al. 2004), and, more recently, the introduction of White Nose Syndrome (WNS; see chapter VII. Bats and Disease). Direct disturbance to suitable cave roosts can be a serious threat and has resulted in the listing of several bat species under the Endangered Species Act (ESA; USFWS 1976), and population declines of more common taxa (O’Shea and Vaughan 1999). Disturbances to caves can be unintentional (bat disturbance from cavers moving through an area, shining lights or talking) or intentional (shooting or hitting bats, burning torpid bats with torches, or setting fires in caves; Speakman et al. 1991). Commercialization of caves for tourism or guano mining has caused partial or complete abandonment of sites by bats (Elliot 2012). Natural disturbances, such as flooding, can also reduce bat population numbers (DeBlase et al. 1965).

Biologists conducting winter cave survey for bats. Photo by J. Siemers.

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In Colorado, karst caves are found primarily in carbonate rocks (Parris 1973; Kolstad 1996) and solution caves are found in gypsum, anhydrite, and quartzite (Reames 2011). Caves are also scattered throughout claystone, alluvial, and talus deposits where they develop along faults and fissures in metamorphic and igneous rock (Parris 1973; Kolstad 1996; Reames 2011). Among cave habitats, areas of karst are known to be most important to Colorado bats (Fig. 2.1) with some notable exceptions, such as a few claystone caves (Davis 1998). Currently, over 1,000 caves are known in Colorado (Derek Bristol, Colorado Cave Survey, pers. comm., 2017), though it is unknown what portion is used by bats. Cave exploration has become more popular, leading to increased year-round visitation at well-known caves (Fish 1999). Many Colorado caves are located at higher elevations which limits access during the winter. However, the popularity of winter recreation such as snowmobiling and skiing has likely increased both cave visitation during winter at these sites and the possibility of disturbing hibernating bats. With increased interest in recreational caving, more people are trying to discover new caves and locate or excavate new passages within known caves (Fish 1999), sometimes using drilling and explosives (Kolstad 1996; Rhinehart 2000).

Figure 2.1. Karst and limestone formations in Colorado extracted from the digital geological map of Colorado (Green 1992).

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Cave access for recreation or research not only risks direct disturbance of bats, but also may introduce invasive diseases, particularly WNS (see chapter VII. Bats and Disease). Since 2007, cave-dwelling bats in the Eastern US have suffered die-offs of 90% or higher due to WNS. Models have shown that areas of Colorado with greater cave concentrations have some of the highest probabilities of susceptibility for introduction of WNS in the country (Ihlo 2013). Consequently, management of cave resources has become increasingly complicated (CPW 2011; USFWS 2011; USFS 2013; Neubaum et al. 2017).

Historically, Colorado cave resources were protected because few people knew their locations or gates were installed to limit access. Olson et al. (2011) found that reduced visitation by recreational cavers and researchers to a known cave hibernacula in Alberta, Canada led to increased bat use over time. Where disturbance is a concern, gating is a common method used to protect bat populations. Use of gates should be weighed carefully as both positive and negative outcomes can occur (Elliot 2012). Currently 30 caves in Colorado are gated to limit human Maternity colony of Towsend’s big-eared bats in a access (D. Bristol and K. Manley, Colorado Cave cave. Photo by J. Siemers. Survey, pers. comm., August 2014). Of these, 12 caves are privately owned with 3 commercially operated as tourist attractions. Ten of the 30 gates were designed to allow some level of bat use. Two additional caves have gates designed only to prevent human access yet continue to have bat use as well. Several gated caves have multiple entrances, some of which are inaccessible to humans but could still be used by bats. In cases where caves were dug open to gain access, gates are designed to minimize changes in variables such as air flow, which in turn prevents alterations to cave climate and protects speleological formation growth and/or persistence. The Townsend’s big-eared bat (Corynorhinus townsendii), a state and federal species of concern, has been found in at least 7 of the gated caves (CPW Bat Database, unpublished data). It is unknown if the level of bat use has changed at most gated sites in Colorado as pre-gating surveys were either not conducted or gates have been installed only recently.

Cave protection has also been formalized through legislation (Jones et al. 2003) such as the 1988 Federal Cave Resources Protection Act (16 USCS 4301 et seq., FCRPA). The FCRPA requires protection of caves on federal lands that have been designated as significant as defined in the act. A number of caves in Colorado have met the criteria and been designated as significant. Three of these caves are gated, of which 2 are bat-friendly, and have resource management plans in place. Other laws and regulations that may provide additional protection for cave resources include: the 1897 Organic Administration Act (16 U.S.C. 551), the 1973 ESA (87 Stat. 884, as amended; 16 U.S.C. 1531), the 1906 Antiquities Act (34; 16 U.S.C. 431 et seq.), and the 1979 Archaeological Resources Protection Act (16 U.S.C. 470aa).

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Bat populations may be negatively impacted by surface disturbances near caves, such as logging, fuels treatments, wildfire, controlled burns, siltation/erosion events, or slash deposition (Poulson 1976; Sheffield et al. 1992; Jones et al. 2003; Elliott 2012). However, specific impacts to bats using caves have not been studied for many of these threats. Surface energy development may disturb caves when drilling intersects these features at a subterranean level or when surface runoff of contaminants and erosion occur at entrances (Brooke 1996). In Colorado, this risk is highest where energy development has intersected caves occurring in non-carbonate rocks, such as clay stone (see chapter VIII. Energy Development). Application of buffer zones and general best management practices (BMP’s) for caves should be implemented (Jones et al. 2003; Elliott 2006, 2012).

Unlike the Eastern U.S., caves in Colorado generally do not support large bat colonies. Historically, efforts to identify use of caves by bats in Colorado were opportunistic in nature relying on occasional reports, often from cavers. A limited number of follow-up investigations were made that resulted in the identification of caves used by relatively large numbers (> 50 individuals) of bats (Armstrong 1972; Finley et al. 1983). Investigations of bat use at caves gained momentum with Navo et al. (2002) documenting swarming activity. This work was followed by efforts to understand what environmental variables influence swarming behavior (Englert 2008; Ingersoll 2010). Siemers (2002) made the first systematic survey of caves in Colorado for bats, observing 8 species, generally in small numbers, across 19 of 99 caves surveyed. The first edition of the Colorado Bat Conservation Plan (Ellison et al. 2004) suggested there is insufficient knowledge regarding caves in Colorado to provide adequate protective conservation and management actions for bats. Select caves on the White River National Forest were periodically surveyed from 2005–2011 (Potter 2005; Mosch 2009) to investigate previous reports of bat use. In 2011, the National Speleological Society’s annual convention was held in Glenwood Springs (Reames 2011), raising concerns about the potential to spread WNS, and its causal agent Pseudogymnoascus destructans (Pd), from infected caves in the eastern US to those in Colorado. Since that time, intensive surveys to investigate seasonal use and swarming at caves on the White River National Forest and Colorado River Valley Field Office of the BLM have improved our understanding of bat use in caves for this part of the state (Neubaum 2016; Siemers and Neubaum 2015).

In this plan, we address four categories of issues related to cave- and karst-inhabiting bats: inadequate knowledge of bat dependence on cave habitat; surface and subsurface land management practices; managing recreation impacts; and intentional disturbance and vandalism.

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INADEQUATE KNOWLEDGE OF BAT DEPENDENCE ON CAVE HABITAT

Current knowledge of bat resources in Colorado caves is insufficient to provide adequate conservation and management actions.

GOAL GAIN A MORE COMPREHENSIVE KNOWLEDGE OF BAT ROOSTING IN COLORADO CAVES INCLUDING IDENTIFYING, PROTECTING, AND RESTORING ECOSYSTEMS AND HABITATS CRITICAL TO THE VIABILITY OF BAT POPULATIONS ASSOCIATED WITH THESE FEATURES. Objective 1: Identify caves that currently support, or historically supported, bat populations.

Objective 2: Identify the ecosystem components and associated habitats that contribute to viability of bat populations using caves.

Objective 3: Standardize protocols for both external and internal surveys of caves to minimize impacts to bats, reduce impacts to other sensitive cave features, and provide standardized comparable data.

Objective 4: Determine the seasonal (summer, transitional, swarming, hibernation) dependence of bats on cave resources by region and species.

MANAGEMENT RECOMMENDATIONS  Inventory caves for bat use, including maternity, hibernation, migration, and swarming use, and monitor those with confirmed use to better understand population dynamics.  Implement the standards presented in the Species Conservation Assessment and Conservation Strategy for the Townsend's big-eared bat (Pierson et al. 1999; see chapter XI: Species Status, Population Trends, and Monitoring)  Conduct surveys of caves identified in the Colorado Parks and Wildlife WNS Surveillance Plan (2012), and by district Forests.

RESEARCH NEEDS

 Develop and improve remote survey techniques including infrared photography, acoustic monitoring, electronic entry and exit counting, and species identification.  Identify characteristics, both external and internal to the cave, to evaluate potential use by bats. These characteristics may include cave microclimate, elevation, access and egress restrictions created by snow, and proximity to foraging and drinking areas.  Utilize radiocarbon analysis using accelerator mass spectrometer techniques to age bones or mummified bat remains to confirm historic use of caves.  Study the relationship between cave water quality and the trace mineral needs of bat species. Monitor water chemistry, especially calcium and sulfate concentration, as well as

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microorganisms, pollutants and contaminants. Investigate the possible relationship between the presence of water resources inside caves and bat roost site preference during all seasons.  Model cave environments to determine optimal roost conditions and factors important for bats. This may include monitoring temperature, humidity, airflow patterns, cave passage geometry and complexity, presence of cave water, and entrance location and cover.  Determine if and why bats are using multiple caves, as is seen for other roost types. What is an individual bat’s fidelity to a given cave?  Investigate the use of caves for swarming. Can the behavior be quantified and does it lead to use of the site as a hibernacula?  Evaluate gate designs used on caves. Do gates inhibit or encourage use of caves by bats? Which caves need gates?  Assess the fungal fauna at caves to identify the diversity and potential surrogate species to Pd that may help predict locations that support Pd and potential outbreaks of WNS.

Bat friendly gate at cave entrance. Photo by D. Neubaum.

SURFACE AND SUBSURFACE LAND MANAGEMENT PRACTICES

Surface and subsurface land management practices can change cave roosting environments and lead to their abandonment by bats. Important associated habitat used for foraging, drinking, and night roosting may also be disturbed by such practices.

GOAL ENCOURAGE SURFACE AND SUBSURFACE LAND MANAGEMENT PRACTICES THAT REDUCE IMPACTS TO BAT POPULATIONS, CONSERVE THEIR USE OF CAVE ROOSTING ENVIRONMENTS, AND PROTECT NEARBY HABITAT ASSOCIATED WITH THESE SITES FOR FEEDING, DRINKING, AND RESTING. Objective 1: Develop and implement surface and subsurface land management practices and plans that protect cave and karst ecosystem components crucial to bat habitat.

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Objective 2: Promote surface land management policies that preserve the integrity of karst- dependent ecosystems and groundwater (Poulson 1976; Brooke 1996; Elliott 2006, 2012).

MANAGEMENT RECOMMENDATIONS  Avoid filling cave entrances, sinkholes, and open karst depressions with slash debris.  Minimize topsoil erosion and the removal of vegetation in karst areas during practices such as timber sales to maintain existing hydrologic and microclimate functions. If water sources, microclimates, and entrance portals to caves are modified bats may abandon them.  Avoid use of persistent pesticides and herbicides in areas where they may permeate into karst systems. Contaminated water supplies may affect bats that drink from these sources, particularly females that may be targeting such resources if they are rich in calcium (Brooke 1996; Adams et al. 2003).  Protect springs and established wetlands in areas that support historically occupied caves. Resources for these recommendations include Jones et al. (2003) and Veni (2006).

RESEARCH NEEDS

 Delineate catchments and recharge zones in karst areas to determine extent of land vulnerable to impact. Objective 3: Promote surface land management policies and guidelines that minimize degradation of subsurface air quality and microclimates. See BMP’s in Elliot (2012) and guidelines in Jones et al. (2003).

MANAGEMENT RECOMMENDATIONS  Preserve natural airflow in and out of occupied cave entrances and passages. Actions that may adversely alter the cave microclimate include back-filling of cave entrances, modifying sinkholes, installing entrance gates or other structures that modify airflow patterns, and digging in cave passages.  Minimize the use of prescribed burning in karst areas and near caves (Pierson et al. 1999). Fire can impact cave and karst features by exposure to smoke and ash, lead to degradation of cave entrances due to increased erosion, and cause leaching of carbon deposits into caves (Jones et al. 2003). Maintain high standards for atmospheric conditions that allow for good ventilation before proceeding with burns around caves (Sheffield et al. 1992; Elliott 2012). Objective 4: Encourage land managers to use guidelines that maintain critical cave resources for bats. Management plans with BMP’s and cave management recommendations should be referenced for bat-specific management guidance.

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MANAGEMENT RECOMMENDATIONS  Identify nearby foraging, drinking and roosting sites critical to bat species. Protecting these features for bats roosting in nearby caves will reduce energy expenditures.  Implement zones of "no impact" or "limited impact" from surface management activities around all caves with significant bat roosts (contact bat biologists from CBWG if guidance is needed).  Require surveys for bat roosts when proposing surface management activities such as timber sales, prescribed burning and road building when they are near caves known to be used by bats. Provide guidelines for such surveys.  Apply seasonal restrictions to avoid disruption of maternity, swarming, hibernation, or other critical life-cycle activities when timber sales or road building are proposed near known roost sites. These buffer zones should reflect the species composition and sensitivity of roost sites. For example, at Townsend’s big-eared bat sites, seasonally restrict timber harvest activities and road building within a 0.25 mi radius buffer around roost sites with bat use. In addition, these activities should be restricted seasonally to avoid disturbance to Townsend’s maternity roosts (early May–late August) and hibernacula (mid October–mid March). The critical time periods of hibernation and maternity activity may vary by species regionally and should be determined by a qualified biologist (Pierson et al. 1999).  Maintain a buffer zone of 2 mi for pesticide spraying around bat roost sites used by species of concern or considered biologically important for a given species. Allow spot applications of herbicides as a weed management tool.  Maintain or improve riparian and wetland habitats near roosts inhabited by species of concern or considered biologically important to a population to achieve healthy and diverse foraging structure.

RESEARCH NEEDS

 Examine the relationships between external characteristics of surface features associated with caves, particularly in karst areas, that may relate to the microclimate in the roost. These features include entrance elevation and configuration, local environmental characteristics, vegetation cover surrounding entrances, and water sources. Monitor the effectiveness of these restrictions to see if they aid bat populations.

Objective 6: Encourage the siting of large scale water impoundment projects in areas other than canyons composed of cliff bands and intact riparian drainages so that caves are not inundated by water and permanently lost.

MANAGEMENT RECOMMENDATIONS  Conduct surveys of bat use pre- and post-development for large scale water impoundments to identify changes in activity levels, displacement from roosts, and increased competition in habitat adjacent to the inundated area.

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 Develop and restore nearby or adjacent riparian zones to provide alternative habitat for displaced bats. Riparian habitat that provides important foraging, drinking, and night roosting habitat is lost when large scale water impoundments are installed (Nilsson and Dynesius 1994; Nilsson and Berggren 2000; Rebelo and Rainho 2009). Ideally, such restoration would use mitigation funds and start well before the impoundment occurs so that the time lag between displacement and newly established and functioning riparian areas is minimal.

RESEARCH NEEDS

 Evaluate the potential habitat loss and population impacts resulting from large scale water impoundment in areas where caves are prevalent (e.g., karst deposits).

MANAGING RECREATION IMPACTS

Recreation impacts to bats using caves may result from casual or organized cavers. Historically, the management of recreational use in caves has not focused on bat viability or use. Cave visitation at inappropriate times can disturb bat colonies resulting in roost abandonment, and the direct or indirect mortality of juvenile or hibernating bats. Managing recreation activities at caves using best management practices will insure continued enjoyment of these resources by recreationists while protecting the sensitive resources of the sites (Elliott 2006, Elliott 2012, Jones et al. 2003).

GOAL DEVELOP AND IMPLEMENT SOUND CAVE RESOURCE MANAGEMENT PRACTICES THAT BENEFIT BATS, AS WELL AS OTHER CAVE RESOURCES. RECRUIT COOPERATIVE SUPPORT FROM THE CAVING, RESEARCH, AND MANAGEMENT COMMUNITIES. Objective 1: Prioritize protection of caves that contain bat species of concern, especially where these species demonstrate high roost fidelity such as at maternity colonies or hibernacula.

Objective 2: Involve recreational cavers in the development of cave management guidelines.

Objective 3: Install bat-compatible closures at caves when necessary to protect sensitive bat populations and other cave resources.

Objective 4: Enforce existing laws and regulations pertaining to wildlife and cave resources.

Objective 5: Consider the need to protect suitable cave roosts where WNS is a concern.

Objective 6: Enlist the caving community to help educate the public about the need for cave resource protection and decontamination protocols to reduce the spread of WNS (https://www.whitenosesyndrome.org/topics/decontamination, Accessed March 5, 2018).

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MANAGEMENT RECOMMENDATIONS  Federal and state agencies, as well as private commercial operations, should enforce WNS decontamination protocols at all caves and the caving community should promote use of such standards.  Consult with agencies, owners, and the caving community to identify caves where bats are currently roosting or have historically roosted.  Develop cave management guidelines that provide for recreational use when consistent with protecting bats and other cave resource values (Jones et al. 2003). The FCRPA provides a basis for developing management guidelines.  Implement protective strategies for all significant cave roost sites. The American Society of Mammalogists recommends guidelines to help protect bat roosts (Sheffield et al. 1992). These guidelines were adopted in the Strategy for the Townsend's big-eared bat (Pierson et al. 1999). In addition, the Colorado Bat Working Group has developed a tool to help managers discern roosts that are biologically important to bats (Neubaum et al. 2017).  Regulate human use in caves with sensitive bat resources by developing cave management plans, cooperative agreements, memoranda of understanding, and cave entry permits for both recreation and research, if appropriate (e.g., USFS 2013).  Consider implementing seasonal or diurnal use restrictions at caves during critical bat use periods. Close caves to recreational use from mid October–mid March to protect hibernacula and from early May–late August to protect maternity colonies using caves if disturbance is likely. Additional closures from late August–mid October may be needed if swarming behavior is occurring. The critical time periods of swarming behavior, hibernation and maternity activity may vary regionally and should be determined by a qualified biologist (Pierson et al. 1999; Neubaum et al. 2017).  When bat compatible gates are required, design structures that minimize changes to the cave microclimate and entrance configuration, and that provide secure access control. Recruit recreational cave user support to construct and install bat gates when possible. Plans for such structures have been developed for many caves (Bat Conservation International, USFWS, and CPW).  Protect caves historically occupied by sensitive bat species.  Monitor numbers of bats at caves before and after management restrictions are put in place to document effectiveness.

RESEARCH NEEDS

 Develop methods to determine if seasonal closures of caves are effective and if so, to what degree.  Investigate if cave visitations during swarming season impacts use by bats. Do impacts vary if visitations only occur by day versus night?

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GOAL MINIMIZE OR PREVENT IMPACTS BY RECREATIONAL CAVE USERS, RESEARCHERS, AND THE GENERAL PUBLIC IN CAVES WHERE BIOLOGICALLY IMPORTANT POPULATIONS OR SENSITIVE SPECIES OF BATS ARE PRESENT. Objective 1: Provide information to cavers, researchers, and other public users about "bat friendly" caving techniques.

Objective 2: Coordinate with owners of private caves to establish protective measures for caves supporting critical bat populations.

Objective 3: Establish seasonal protection measures for caves that support critical populations of bats, including the construction of bat compatible gates when deemed necessary.

Objective 4: Standardize protocols for both external and internal surveys to minimize stress to bats and impacts to other sensitive cave features.

MANAGEMENT RECOMMENDATIONS  Encourage agencies and private cave owners to require cave visitors to utilize "bat-friendly" caving techniques.  Offer support or assistance to cave managers (particularly for show caves) by providing educational programs or materials relating to bat conservation.  Offer bat management and conservation technical support to private cave owners.

RESEARCH NEEDS

 Evaluate the impact of entrance signs and other education efforts on caving practices.  Investigate alternative caving and research techniques that reduce impacts to bats.  Research the human-use trends in individual caves that are past, current or potential bat habitats to determine appropriate management strategies. Supporting information may be obtained from entry registers, caving publications, personal accounts, and surveillance devices.  Determine if gate design at caves affects bat use such as swarming behavior. Do gates impede ingress and egress activities associated with swarming? Conduct monitoring surveys to answer such questions pre and post gate installation.

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INTENTIONAL DISTURBANCE AND VANDALISM

GOAL REDUCE OPPORTUNITIES FOR INTENTIONAL DISTURBANCE OR VANDALISM IN CAVES WHERE BIOLOGICALLY IMPORTANT POPULATIONS OR SENSITIVE SPECIES OF BATS ARE PRESENT. Objective 1: Educate the community about the importance and sensitivity of cave resources, especially where vandalism has occurred.

Objective 2: Consider installing educational and warning signs at sensitive caves used by bats where disturbance and vandalism is occurring.

Objective 3: Monitor cave roost sites where disturbance/vandalism has occurred with devices such as trail or surveillance cameras.

Objective 4: Consider installation of bat friendly gates at caves where vandalism cannot be controlled and significant or sensitive bat populations are present and/or in decline.

MANAGEMENT RECOMMENDATIONS  Encourage agencies and private cave owners to ask cave visitors to practice "bat-friendly" caving techniques.  Utilize left over mitigation funds from mining and energy development to pay for gate installation at vandalized caves. Consider building mitigation funding into the planning process for such activities in areas where known cave roosts are present.

RESEARCH NEEDS

 Evaluate the impact of entrance signs and other education efforts on vandalism and intentional disturbance.  Research trends in vandalism and intentional disturbance in caves that are past, current or potential bat habitats to determine appropriate management strategies.

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CPW (Colorado Parks and Wildlife). 2011. White-Nose Syndrome in bats response plan. Denver, CO. Available at http://cpw.state.co.us/learn/Pages/WildlifeHealthWNS.aspx. CPW (Colorado Parks and Wildlife). 2012. Bat “White-Nose Syndrome” surveillance plan and protocols: 2011-2012. Denver, CO. Available at http://cpw.state.co.us/Documents/Research/WildlifeHealth/CPW_BatWNSsurveillanceplan_20112 012.pdf. Davis, D. G. 1998. The discovery and survey of the Anvil Points claystone caves. Rocky Mountain Caving 15:18-22. DeBlase, A. F., S. R. Humphrey, and K. S. Drury. 1965. Cave flooding and mortality in bats in Wind Cave, Kentucky. Journal of Mammalogy 46:96. Elliott, W. R. 2006. Biological dos and don'ts for cave conservation and restoration. Pages 33-42 in V. Hildreth-Werker and J. C. Werker , editors. Cave conservation and restoration. National Speleological Society, Huntsville, AL. Elliott, W. R. 2012. Protecting cave life. Pages 624-631 in W. B. White and D. C. Culver, editors. Encyclopedia of caves. Elsevier Academic Press, Boston. Ellison, L. E., M. B. Wunder, C. A. Jones, C. Mosch, K. W. Navo, K. Peckham, J. E. Burghardt, J. Annear, R. West, J. Siemers, R. A. Adams, and E. Brekke. 2004. Colorado bat conservation plan. Colorado Committee of the Western Bat Working Group. Englert, A. C. 2008. Chemical recognition and swarming behavior in bats. M.A. Thesis. University of Colorado, Denver. Denver, CO. Finley, R.B., Jr., W. Caire, and D.E. Wilhelm. 1983. Bats of the Colorado oil shale region. Great Basin Naturalist 43:554-560. Fish, L. 1999. A summary of Groaning Cave impact and access for the years 1980-1997. Rocky Mountain Caving 16:9-11. Green, G. N., 1992. The digital geologic map of Colorado in ARC/INFO format: US Geological Survey Open-File Report 92-507, US Geological Survey, Denver. Ihlo, C. M. 2013. Predicting the spread of white-nose syndrome in bats: a strategy for prioritizing resources. M.A. Thesis. Duke University, Durham, NC. Ingersoll, T. E., K. W. Navo, and P. De Valpine. 2010. Microclimate preferences during swarming and hibernation in the Townsend's big-eared bat, Corynorhinus townsendii. Journal of Mammalogy 91:1242-1250. Jones, W. K., H. H. Hobbs III, C. M. Wicks, R. R. Currie, L. D. Hose, R. C. Kerbo, J. R. Goodbar, and J. Trout, editors. 2003. Recommendations and guidelines for managing caves on protected lands. Karst Waters Institute, Special Publication 8, Charles Town, West Virginia. Kolstad, R. 1996. The caves and karst of Colorado: A guidebook for the 1996 Convention of the National Speleological Society : Salida, Colorado, August 5-9, 1996. National Speleological, Society, Huntsville, Alabama.

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McCracken, G. F. 1989. Cave conservation: special problems of bats. Bulletin of the National Speleological Society 51:49-51. Medellin, R. A., R. Wiederholt, and L. Lopez-Hoffman. 2017. Conservation relevance of bat caves for biodiversity and ecosystem services. Biological Conservation 211:45-50. Mosch, C. J. 2009. Report on Premonition Cave and Fixin’-to-Die Cave. White River National Forest Bat Habitat Study Project. Rocky Mountain Cave Resources. Navo, K. W., S. G. Henry and T. E. Ingersoll. 2002. Observations of swarming by bats and band recoveries in Colorado. Western North American Naturalist 62:124-126. Neubaum, D. J. 2016. Surveillance, monitoring, and natural history investigations of bats related to White Nose Syndrome within the Colorado River Valley Field Office: 2016. Colorado Parks and Wildlife, Grand Junction, CO. Neubaum, D. J., K. W. Navo, and J. L. Siemers. 2017. Guidelines for defining biologically important bat roosts: A case study from Colorado. Journal of Fish and Wildlife Management 8:272-282. Nilsson, C., and K. Berggren. 2000. Alterations of riparian ecosystems caused by river regulation: Dam operations have caused global-scale ecological changes in riparian ecosystems. How to protect river environments and human needs of rivers remains one of the most important questions of our time. BioScience 50:783-792. Nilsson, C. and M. Dynesius. 1994. Ecological effects of river regulation on mammals and birds: A review. Regulated Rivers: Research and Management 9:45-53. Olson, C. R., D. P. Hobson, and M. J. Pybus. 2011. Changes in population size of bats at a hibernaculum in Alberta, Canada, in relation to cave disturbance and access restrictions. Northwestern Naturalist 92:224-230. O'Shea, T. J., and T. A. Vaughan. 1999. Population changes in bats from central Arizona: 1972 and 1997. The Southwestern Naturalist 44:495-500. O'Shea, T. J., L. E. Ellison, and T. R. Stanley. 2004. Survival estimation in bats: Historical overview, critical appraisal, and suggestions for new approaches. Pages 297-336 in W. L. Thompson, editor. Sampling rare and elusive species. Island Press, Washington, D. C. Parris, L. E. 1973. Caves of Colorado. Pruett Publishing Company, Boulder, CO. Parsons, K. N., G. Jones, and F. Greenaway. 2003. Swarming activity of temperate zone microchiropteran bats: effects of season, time of night and weather conditions. Journal of Zoology 261:257. Pierson, E. D. 1998. Tall trees, deep holes, and scarred landscapes. Pages 309-325 in T. H. Kunz, and P. A. Racey, editors. Bat Biology and Conservation. Smithsionian Institution Press, Washington. Pierson, E.D., M.C. Wackenhut, J.S. Altenbach, P. Bradley, P. Call, D.L. Genter, C.E. Harris, B.L. Keller, B. Lengus, L. Lewis, B. Luce, K.W. Navo, J.M. Perkins, S. Smith, and L. Welch. 1999. Species conservation Assessment and strategy for Townsend’s big-eared bat (Corynorhinus townsendii townsendii and Corynorhinus townsendii pallescens). Idaho Conservation Effort, Idaho Department of Fish and Game, Boise, Idaho. 63 pp.

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Potter, K. 2005. Hubbard Cave: Overview, Biotic History, and Winter Survey Report, March 2005. Report on file with the White River National Forest. Supervisor’s Office, Glenwood Springs, CO. Poulson, TL. 1976. Management of biological resources in caves. Pages 46-52 in Proceedings of the National Cave Management Symposium, Albuquerque. New Mexico. 1975. Albuquerque (NM): Speleobooks. Rabinowitz, A., and M. D. Tuttle. 1980. Status of summer colonies of the endangered gray bat in Kentucky. Journal of Wildlife Management 44:955-960. Reames, S. 2011. Caves and Karst of NW Colorado: a guidebook for the 2011 convention of the National Speleological Society. National Speleological Society, Huntsville, AL. Rebelo, H., and A. Rainho. 2009. Bat conservation and large dams: spatial changes in habitat use caused by Europe's largest reservoir. Endangered Species Research 8:61-68. Rhinehart, R. 2000. Decade of discovery. Rocky Mountain Caving 17:11-13 Richter, A. R., S. R. Humphrey, J. B. Cope, and V. Brack. 1993. Modified cave entrances - thermal effect on body-mass and resulting decline of endangered Indiana bats (Myotis sodalis). Conservation Biology 7:407-415. Schowalter, D. B. 1980. Swarming, reproduction, and early hibernation of Myotis lucifugus and M. volans in Alberta, Canada. Journal of Mammalogy 61:350-354. Sheffield, S. R., J. H. Shaw, G. A. Heidt, and L. R. McClenaghan. 1992. Guidelines for the protection of bat roosts. Journal of Mammalogy 73:707-710. Siemers, J. L. 2002. A survey of Colorado’s caves for bats. Colorado Natural Heritage Program, Colorado State University. Fort Collins, CO. Siemers, J. L. and D. J. Neubaum. 2015. White River National Forest cave bat survey and monitoring – 2015. Colorado Natural Heritage Program, Colorado State University. Fort Collins, CO. Speakman, J. R., P. I. Webb, and P. A. Racey. 1991. Effects of disturbance on the energy expenditure of hibernating bats. Journal of Applied Ecology 28:1087-1104. Tuttle, M. D. 2000. Where the bats are Part III: Caves, cliffs, and rock crevices. Bats 18:6-11. Tuttle, M. D. 2003. Estimating population sizes of hibernating bats in caves and mines. Pages 31-39 in T. J. O'Shea, and M. A. Bogan, editors. Monitoring trends in bat populations of the United States and Territories: Problems and prospects. US Geological Survey, Biological Resources Discipline, Information and Technology Report, USGS/BRD/ITR--2003-0003. USFS (US Forest Service). 2013. Environmental Assessment for Cave and Abandoned Mine Management for White Nose Syndrome. Denver, CO. USFWS (US Fish and Wildlife Service). 1976. To the list of endangered and threatened species, Fish and Wildlife Service added the gray bat, Mexican wolf, and two butterfly species. Federal Register 41:17736. USFWS (US Fish and Wildlife Service). 2011. A national plan for assisting states, federal agencies, and tribes in managing white-nose syndrome in bats. Available at:

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https://www.whitenosesyndrome.org/national-plan/white-nose-syndrome-national-plans; Accessed 4/23/14). Veni, G. 2006. Karst hydrology: protecting and restoring caves and their hydrologic systems. Pages 121- 132 in V. Hildreth-Werker and J. C. Werker, editors. Cave conservation and restoration. National Speleological Society, Huntsville, AL. White, D. H., and J. T. Seginak. 1987. Cave gate designs for use in protecting endangered bats. Wildlife Society Bulletin 15:445-449.

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III. ROCK CREVICE MANAGEMENT PRACTICES

By Daniel J. Neubaum

Of the roughly 34 bat species that regularly occur in the western regions of North America, 25 of these species use rock crevice or cavity roosts (Bogan et al. 2003). As O’Shea and Bogan (2003) emphasize, the lack of knowledge about the use of such structures by bats is largely due to the difficulty of observing and studying them in such situations. With the recent improvements made to miniature radiotransmitters, several studies have recently described the characteristics of rock crevices used by several bat species in Colorado and western North America. Summer roosts in rock crevices may be used by bats even in areas where other suitable roosts such as trees, caves, and buildings exist. Chung- MacCoubrey (2008) tracked reproductive females of several bat species to rock crevices and erosion tubes in the Book Cliffs near Grand Junction, CO. Work by O’Shea et al. (2011) and Snider et al. (2013) at Mesa Verde National Park found that several species, including spotted bats (Euderma maculatum), little brown myotis (Myotis lucifugus, noted as Myotis occultus in study), long-eared myotis (M.evotis), fringed myotis (M. thysanodes), and long-legged myotis (M. volans), used rock crevices as maternity roosts despite the availability of potential tree roosts. Similar findings in Colorado National Monument documented 10 species using rock crevices as maternity roosts, generally on east-to-southeast facing cliffs (Neubaum 2017). Male pallid bats (Antrozous pallidus) were found using only rock crevices, typically in cliff faces, as summer bachelor roosts in southeast Colorado (Schorr and Siemers 2013). Navo and Gore (2001) noted a maternity colony of big free-tailed bats (Nyctinomops macrotis) using a rock crevice in west-central Colorado, which corresponds with findings for this species in Big brown bat in rock crevice. Photo adjacent western states. Recent radiotracking of little brown by D. Neubaum. myotis in the Crystal River Valley found these bats leaving maternity roosts in anthropogenic structures and using rock crevices and boulder fields, among other features, as fall transition roosts and presumed winter hibernacula (Neubaum 2018). Similarly, big brown bats (Eptesicus fuscus) undertook short migrations in elevation from maternity roosts in urban structures along the Front Range of north-central Colorado to winter hibernacula in rock crevices in the adjacent foothills and mountains (Neubaum et al. 2006). Thus, use of such rock crevices by bats as summer maternity roosts, fall transition roosts, and hibernacula in Colorado is more extensive than supported by the literature as recently as a decade ago. Rock resources in the form of cliffs, talus, and boulders are abundant across much of Colorado (Fig. 3.1).

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Figure 3.1. Terrain Roughness Index of Colorado where brighter white colors reflect steeper, more rugged terrain that is more likely to be composed of cliff faces, talus slopes, and other rock crevice resources at the ground surface that could be used by bats (layer development by M. Flenner, CPW GIS section). Management implications for bats using rock crevices as roosts in Colorado may be particularly important in forested areas where large surface disturbances such as fire, logging, or fuel reduction have occurred (Sheffield et al. 1992; see chapter IV. Forest and Woodland Management Practices). In desert and rolling plains ecosystems where trees are rare, surface mining, collection of landscape material and energy exploration may have an impact on rock crevice and cavity roosting bats (see chapters I. Mining Issues and V. Rangeland Management). In addition, a geographical region where a plains–mountain interface occurs also provides a likely area where bats may undertake local migrations to use rock crevices as hibernacula during the winter period (Neubaum et al. 2006). Water impoundments in large valleys where scree slopes and cliff bands are submerged pose significant risks to local bat populations through the loss of roost sites and riparian foraging areas (Rebelo and Rainho 2009). Thus, management considerations should not overlook the importance of seasonal variation in the use of rock crevices by bats. Recreational climbing is increasing in popularity in Colorado (e.g., Jefferson County Open Space, http://climbjeffco.com/ ). The cracks and crevices in rock faces that provide attractive climbing routes

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may also provide sites for rock crevice roosting bats (e.g., Mountain Project, https://www.mountainproject.com/area/106527523/bat-cave-area ). Sixteen of 19 Colorado bat species are known to roost in rock crevices along cliff faces that could potentially be disturbed by recreational climbing. However, some species are more likely to be disturbed than others based on the type of rock crevices they typically use. For example, pallid, spotted and big free-tailed bats are known to use large cliff faces (Haymond et al. 2002; O’Shea et al. 2011; Schorr and Siemers 2013; Neubaum 2017) that tend to be popular with climbers while western long-eared myotis in summer (Snider et al. 2013) and big brown bats in autumn (Neubaum et al. 2006) have been found using small cliffs and boulders that are less desirable for such activities. Recreational climbing may disturb or displace bats using rock crevices as maternity roosts if the route is climbed often, increasing the threats to species of concern (Adams and Thibault 2000). Threats related to recreational climbing have been well documented with cliff nesting birds (Boyle and Samson 1985; Camp and Knight 1998) and have led to seasonal route closures. Similar seasonal climbing route closures have recently been implemented by the city of Boulder for bats (https://bouldercolorado.gov/osmp/bat-roosting-closures). Projects like Climbers for Bat Conservation are engaging the climbing community in a collaborative effort to expand our knowledge of crevice roosting bats and examine the potential for impacts from climbing (Fig. 3.2; http://www.climbersforbats.colostate.edu/). The project allows climbers a venue to report how often bat-to-climber encounters are occurring, identify roost sites, and provide new knowledge about bat roosting ecology.

Disturbance of bats using rock crevices is likely to occur through both inadvertent and intentional acts. For example, a documented big free-tail roost in southwestern Colorado (Navo and Gore 2001) has experienced vandalism such as graffiti applied to the rock face below the roost and party activity at the site. The visitors are likely unaware that the bats are using the site but the disturbance may have led to its abandonment as several subsequent surveys in recent years have not found a colony present (D. Neubaum, unpublished data, 2018). O’Shea and Vaughn (1999) noted declining populations of bats, a change in species composition, and roost abandonment of rock crevices and cavities and suggested it may be the result of increased recreational use at the site. Although such occurrences are likely common, reports tend to be anecdotal and infrequent. Sampling historic locations where rock crevice and cavity records exist for bats would help determine how prevalent the issue of disturbance is and suggest avenues of preventing such disturbances in the future.

Although use of rock crevices has been documented for most bat species in Colorado, insight for a number of questions continue to lack defensible data, including the characteristics of crevices used in the selection of a given site by different species and in different habitats and seasons, as well as improved knowledge about colony dynamics (O’Shea and Bogan 2003). We address four categories of issues for rock crevice and cavity roosting bats: inadequate knowledge of bat dependence on rock crevice habitat; surface and subsurface management practices; managing recreation impacts; and intentional disturbance/vandalism.

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Figure 3.2. Schematic chart of the relationship between climbers, bats, and conservation. This was developed during meetings between climbers, biologists, and land managers as part of Climbers for Bat Conservation. Artwork by ConverSketch (ConverSketch.com; Karina Branson). Photo by Rob Schorr.

INADEQUATE KNOWLEDGE OF BAT DEPENDENCE ON ROCK CREVICE HABITAT

Current knowledge of bat resources in Colorado rock crevices is insufficient to provide adequate conservation and management actions.

GOAL GAIN A COMPREHENSIVE KNOWLEDGE OF BAT ROOSTING IN COLORADO ROCK CREVICES INCLUDING IDENTIFYING, PROTECTING AND RESTORING ECOSYSTEMS AND HABITATS CRITICAL TO THE VIABILITY OF BAT POPULATIONS ASSOCIATED WITH THESE FEATURES. Objective 1: Identify rock crevices that currently support or historically supported bat populations, particularly those within management areas of interest where threat potential is high (e.g., popular climbing areas, large scale water impoundments, areas vulnerable to catastrophic fire events).

Objective 2: Identify the ecosystem components and associated habitats that contribute to viability of bat populations using rock crevices.

Objective 3: Standardize protocols for external surveys of rock crevices to minimize impacts to bats, reduce impacts to other sensitive cliff features (e.g., raptor nests), and provide standardized comparable data.

Objective 4: Determine the seasonal (summer, transitional, swarming, hibernation) dependence of bats on rock crevice features by ecoregion and species.

MANAGEMENT RECOMMENDATIONS  Inventory rock crevices for bat use during maternity, hibernation, migration, and swarming seasons, and monitor those with confirmed use to better understand population dynamics.  Conduct surveys of rock crevices identified by previous inventory efforts.

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 Management of rock crevices used by bats should follow recommendations established for caves to limit the introduction or spread of White Nose Syndrome (WNS), and its causal agent Pseudogymnoascus destructans (Pd), when appropriate.

RESEARCH NEEDS

 Identify characteristics, both external and internal to the rock crevice to evaluate potential for future use by bats. These characteristics may include microclimate, aspect, elevation, and proximity to foraging and drinking areas.  Model rock crevice environments to determine optimal roost conditions and factors important for bats. This may include monitoring temperature, humidity, airflow patterns, proximity to water, and location and cover at the entrance.  Determine if and why bats that use rock crevices roost switch as is seen for other roost types. What is an individual bats fidelity to a given rock crevice?  Assess the fungal fauna in rock crevice roosts to identify the diversity and potential Pd surrogate species that may help predict locations that support Pd and potential outbreaks of WNS.

Arrows point to rock crevices where male pallid bats were found roosting in southeastern Colorado. Photo by D. Neubaum.

SURFACE AND SUBSURFACE MANAGEMENT PRACTICES

Surface and subsurface land management practices can change rock crevice roosting environments and lead to their abandonment by bats. Important associated habitat used for foraging, drinking, and night roosting may also be disturbed by such practices.

GOAL ENCOURAGE SURFACE AND SUBSURFACE LAND MANAGEMENT PRACTICES THAT REDUCE IMPACTS TO BAT POPULATIONS, ROCK CREVICE ROOSTING ENVIRONMENTS, AND NEARBY HABITAT ASSOCIATED WITH THESE SITES FOR FEEDING, DRINKING, AND RESTING.

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Objective 1: Encourage land managers to use guidelines that maintain critical rock crevice resources for bats. Management plans with best management practices (BMP’s) should be referenced for bat- specific management guidance.

MANAGEMENT RECOMMENDATIONS  Identify nearby foraging, drinking and roosting sites critical to rock crevice-obligate or -affiliate bat species. Protecting these features for bats roosting in nearby rock crevices will reduce their energy expenditures.  Implement zones of "no impact" or "limited impact" from surface management activities around known rock crevice roosts (contact bat biologists from CBWG if guidance is needed).  Apply seasonal restrictions to avoid disruption of maternity, swarming, hibernation, or other critical life-cycle activities when surface management activities such as timber sales and road building are proposed near known roost sites. These buffer zones should reflect the species composition and sensitivity of roost sites. For example, at Townsend’s big-eared bat sites, seasonally restrict timber harvest activities and road building within a 0.25mi radius buffer around roost sites with bat use. In addition, these activities should be restricted seasonally to avoid disturbance to Townsend’s maternity roosts (early May–late August) and hibernacula (mid October–mid March). The critical time periods of hibernation and maternity activity may vary by species regionally and should be determined by a qualified biologist (Pierson et al. 1999).  Maintain or improve riparian and wetland habitats near roosts, which are inhabited by species of concern or considered biologically important to a population, to achieve healthy and diverse foraging structure.

RESEARCH NEEDS

 Study use of rock crevices as roosts before and after large scale forest alterations such as fire, beetle kill, and timber sales.

Objective 2: Encourage the siting of large scale water impoundment projects in areas other than canyons composed of cliff bands and intact riparian drainages so that rock crevice roosts and associated habitat are not inundated by water and permanently lost.

MANAGEMENT RECOMMENDATIONS  Avoid construction of large scale water impoundments in drier portions of the state, where rock crevices appear to be utilized more extensively by a wide array of bat species, if alternative sites exist (Nilsson and Berggren 2000).  Conduct surveys of bat use pre- and post-development for large scale water impoundments to identify changes in activity levels, displacement from roosts, and increased competition in habitat adjacent to the inundated area.  Develop and restore nearby or adjacent riparian zones to provide alternative habitat for displaced bats. Riparian habitat that provides important foraging, drinking, and night roosting

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habitat is lost when large scale water impoundments are installed (Nilsson and Dynesius 1994; Rebelo and Rainho 2009). Ideally, such restoration would use mitigation funds and start well before the impoundment occurs so that the time lag between displacement and newly established and functioning riparian areas is minimal.

RESEARCH NEEDS

 Evaluate the potential habitat loss and population impacts resulting from large scale water impoundment in areas where rock crevices and cavities are prevalent (e.g., canyons).  Investigate the dependence of bats on larger riparian/river systems as ephemeral water sources are lost or where they are rare. Climate change may reduce the number of ephemeral water sources in areas with drier climates (Adams and Hayes 2008) or where catastrophic fire events fill them with silt (O’Shea et al. 2011).  Evaluate use by bats of newly created riparian areas along the edges of water impoundments.

Rock crevices utilized by bats during summer in cliff faces and autumn/winter in talus. Photos by D. Neubaum

MANAGING RECREATION IMPACTS

Recreation impacts to bats using rock crevices may occur from disturbance by rock climbers. Recreational climbing at high activity levels may displace roosting bats and compound threats to species of concern.

GOAL DEVELOP AND IMPLEMENT SOUND ROCK CREVICE RESOURCE MANAGEMENT PRACTICES THAT BEST BENEFIT BATS, AS WELL AS OTHER ROCK CREVICE AND CLIFF RESOURCES (CAMP AND KNIGHT 1998). RECRUIT COOPERATIVE SUPPORT FROM THE CLIMBING, RESEARCH, AND MANAGEMENT COMMUNITIES. Objective 1: Prioritize protection of rock crevices that contain bat species of concern, especially where these species demonstrate high roost fidelity such as at maternity colonies or hibernacula.

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Objective 2: Involve recreational climbers in the process of developing rock crevice/cliff management guidelines in areas where climbing is popular.

Objective 3: Consider the need to protect suitable rock crevice roost sites used by bats by implementing seasonal closures.

Objective 6: Enlist the climbing community to help educate the public about the importance of crevice habitats to bats and the need to report bat use of rock crevices.

MANAGEMENT RECOMMENDATIONS  Consult with agencies, owners, and the climbing community to identify rock crevices where bats are currently roosting or have historically roosted.  Develop rock crevice management guidelines that provide for recreational use when consistent with protecting bats and other cliff resource values.  Implement protective strategies for all significant rock crevice roost sites. The American Society of Mammalogists recommends guidelines to help protect bat roosts (Sheffield et al. 1992). These guidelines were adopted in the Strategy for the Townsend's big-eared bat (Pierson et al. 1999). In addition, the Colorado Bat Working Group has developed a tool to help managers discern roosts that are biologically important to bats (Neubaum et al. 2017).  Regulate human use for rock crevice roosts with sensitive bat resources by developing climbing management plans, cooperative agreements, and memoranda of understanding, if appropriate.  Implement seasonal or diurnal use restrictions at known rock crevice roosts during critical bat use periods. Close climbing routes to recreational use from mid October–mid March to protect hibernacula if conditions are warranted and from early May–late August to protect maternity colonies using shallow rock crevices (Neubaum et al. 2017). Additional closures from late August–mid October may be needed if swarming behavior is occurring. The critical time periods of swarming behavior, hibernation and maternity activity may vary regionally and should be determined by a qualified biologist (Pierson et al. 1999).  Protect rock crevices historically occupied by sensitive bat species.  Monitor numbers of bats at rock crevice roosts before and after management restrictions are put in place to document effectiveness of actions.

RESEARCH NEEDS

 Develop methods to determine if seasonal closures of cliffs with rock crevice roosts are effective and, if so, to what degree.  Determine if rock crevice roosts used as hibernacula provide suitable microclimates to harbor Pd to inform disease spread management strategies.

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GOAL MINIMIZE IMPACTS OF RECREATIONAL CLIMBING ON CREVICE-ROOSTING BATS THROUGH EDUCATION AND PROACTIVE MANAGEMENT. Objective 1: Work with the local climbing communities to educate members about the importance of rock crevices to bats and the potential for disturbance by recreational climbing during critical time periods (See the Climbers for Bat Conservation program developed by Colorado Natural Heritage Program, http://www.climbersforbats.colostate.edu/).

Objective 2: Identify localities where recreational climbing activities are high and/or increasing, and may impact bats. Work with management agencies and the climbing community to develop a management plan that helps minimize negative impacts.

Objective 3: Identify sites of overlap where significant bat roosts may occur in cliffs or rock crevices and where future climbing activities may become popular.

Objective 4: Enlist the climbing community to report encounters with bats while climbing so that a better understanding of the threat can be assessed (See the Climbers for Bat Conservation program).

MANAGEMENT RECOMMENDATIONS  Fund survey efforts to identify roosts for different bat species in areas where climbing is popular to determine if conflicts may be occurring.  Encourage grass roots efforts such as the Climbers for Bat Conservation program as a way of learning about bat/climber encounters and roost sites (http://www.climbersforbats.colostate.edu/).

RESEARCH NEEDS

 Are all rock crevices created equal or is selection by bats occurring? Determine if crevice- roosting bats are selecting specific rock crevices or areas related to seasonal or regional variations.  Research the extent of impacts to crevice-roosting bats resulting from recreational climbing.

INTENTIONAL DISTURBANCE AND VANDALISM

GOAL REDUCE OPPORTUNITIES FOR INTENTIONAL DISTURBANCE OR VANDALISM IN ROCK CREVICES WHERE BIOLOGICALLY IMPORTANT POPULATIONS OR SENSITIVE SPECIES OF BATS ARE PRESENT.

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Objective 1: Educate the community about the importance and sensitivity of rock crevice resources, especially where vandalism has occurred.

Objective 2: Consider installing educational and warning signs at sensitive rock crevices used by bats where disturbance and vandalism is occurring.

Objective 3: Monitor rock crevice roost sites where disturbance/vandalism has occurred with devices such as trail or surveillance cameras.

MANAGEMENT RECOMMENDATIONS  Promote public education about the effects of vandalism at or near sites where bats use rock crevices.

RESEARCH NEEDS

 Evaluate the impact of entrance signs and other education efforts on vandalism, and intentional disturbance.  Survey historic locations where rock crevice and cavity records exist for bats to determine how prevalent vandalism and intentional disturbance is and suggest avenues for preventing such activities.

LITERATURE CITED Adams, R. A., and M. A. Hayes. 2008. Water availability and successful lactation by bats as related to climate change in arid regions of western North America. Journal of Animal Ecology 77:1115-1121. Adams, R. A., and K. M. Thibault. 2000. Location and distribution of diurnal roosts, roost site parameters, home ranges, and water use of Boulder County bats. Boulder County Open Spaces, Boulder, CO. M. A. Bogan,P. M. Cryan, E. W. Valdez, L. E. Ellison, and T. J. O'Shea. 2003. Western crevice and cavity- roosting bats. Pages 69-77 in O'Shea, T. J., and M. A. Bogan, editors. 2003. Monitoring trends in bat populations of the United States and territories: problems and prospects: US Geological Survey, Biological Resources Discipline, Information and Technology Report, USGS/BRD/ITR--2003-0003, 274 p. Boyle, S. A. and Samson, F. B. 1985. Effects of nonconsumptive recreation on wildlife: a review. Wildlife Society Bulletin. 13(2):110-116. Camp, R. J. and Knight, R. L. 1998. Rock climbing and cliff bird communities at Joshua Tree National Park, California. Wildlife Society Bulletin. 26(4):892-898. Chung-MacCoubrey, A. L. 2008. Book Cliff Survey for BLM Sensitive Bats. USDA Forest Service- Rocky Mountain Research Station. Report Interagency Agreement No. BLM-IA #06-IA-11221602-150. Haymond, S., M. A. Bogan, E. W. Valdez, and T. J. O’Shea. 2002. Ecology and status of the big free-tailed bat (Nyctinomops macrotis) in southeastern Utah with comments on Allen's big-eared bat (Idionycteris phyllotis), P. 22 pp (B. R. D. US Geological Survey, Midcontinent Ecological Science

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Center, Department of Biology, University of New Mexico, ed.). US Geological Survey, Albuquerque, NM. Navo, K. W., and J. A. Gore. 2001. Distribution of the big free-tailed bat (Nyctinomops macrotis) in Colorado. The Southwestern Naturalist 46:370-376. Neubaum, D. J. 2017. Bat composition and roosting habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 to 2016. Colorado Parks and Wildlife. Grand Junction, CO. Neubaum, D.J. 2018. Unsuspected retreats: autumn roosts and presumed hibernacula used by little brown myotis in Colorado. Manuscript submitted for publication. Neubaum, D. J., K. W. Navo, and J. L. Siemers. 2017. Guidelines for defining biologically important bat roosts: A case study from Colorado. Journal of Fish & Wildlife Management 8:272-282. Neubaum, D. J., T. J. O'Shea, and K. R. Wilson. 2006. Autumn migration and selection of rock crevices as hibernacula by big brown bats in Colorado. Journal of Mammalogy 87:470-479. Nilsson, C., and K. Berggren. 2000. Alterations of riparian ecosystems caused by river regulation: dam operations have caused global-scale ecological changes in riparian ecosystems. How to protect river environments and human needs of rivers remains one of the most important questions of our time. BioScience 50:783-792. Nilsson, C. and M. Dynesius. 1994. Ecological effects of river regulation on mammals and birds: a review. Regulated Rivers: Research and Management 9:45-53. O'Shea, T. J., and M. A. Bogan, editors. 2003. Monitoring trends in bat populations of the United States and territories: problems and prospects: US Geological Survey, Biological Resources Discipline, Information and Technology Report, USGS/BRD/ITR--2003-0003, 274 p. O'Shea, T. J., and T. A. Vaughan. 1999. Population changes in bats from central Arizona: 1972 and 1997. The Southwestern Naturalist 44:495-500. O'Shea, T. J., P. Cryan, E. A. Snider, E. W. Valdez, L. E. Ellison, and D. J. Neubaum. 2011. Bats of Mesa Verde National Park, Colorado: composition, reproduction, and roosting habits. Monographs of the Western North American Naturalist 5:1-19. Pierson. E. D., M. C. Wackenhut, J. S. Altenbach, P. Bradley, P. Call, D. L. Genter, C. E. Harris, B. L. Keller, B. Lengus, L. Lewis, B. Luce, K. W. Navo, J. M. Perkins, S. Smith, and L. Welch. 1999. Species conservation Assessment and strategy for Townsend’s big-eared bat (Corynorhinus townsendii townsendii and Corynorhinus townsendii pallescens). Idaho Conservation Effort, Idaho Department of Fish and Game, Boise, Idaho. 63 pp. Rebelo, H., and A. Rainho. 2009. Bat conservation and large dams: spatial changes in habitat use caused by Europe's largest reservoir. Endangered Species Research 8:61-68. Schorr, R. A., and J. L. Siemers. 2013. Characteristics of roosts of male pallid bats (Antrozous pallidus) in southeastern Colorado, Southwestern Naturalist 58:470-475.

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Sheffield, S. R., J. H. Shaw, G. A. Heidt, and L. R. McClenaghan. 1992. Guidelines for the Protection of Bat Roosts. Journal of Mammalogy 73:707-710. Snider, E. A., P. M. Cryan, and K. R. Wilson. 2013. Roost selection by western long-eared myotis (Myotis evotis) in burned and unburned piñon--juniper woodlands of southwestern Colorado. Journal of Mammalogy 94:640-649.

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IV. FOREST AND WOODLAND MANAGEMENT PRACTICES

By Mikele L. Painter, Daniel J. Neubaum, and Kirk W. Navo

Approximately 34 percent of the land in Colorado is dominated by trees (Schrupp et al. 2000). Depending on elevation, topography, water availability, and disturbance history, the various forest types are mixed on the landscape and with other cover types like grassland, shrubland, rocks, and cliffs. The Colorado Gap Analysis Project (Schrupp et al. 2000) identifies several forest types across the state:

 Evergreen forests (e.g., Engelmann spruce, subalpine fir, lodgepole pine, bristlecone pine, limber pine, Douglas-fir, ponderosa pine, blue spruce, white fir, and “mixed-conifer” forests; this category also includes woodlands that typically have a moderate to low tree density such as pinyon pine and juniper);  Deciduous forest (i.e., aspen);  Forest-dominated wetland/riparian land (e.g., cottonwood, aspen, boxelder, willow trees, conifers in wetlands)

Bats occupy all of these forest types, and exploit the resources within them in a variety of ways. At least 9 species of Colorado bats typically use forest and woodland ecosystems for roosting and foraging habitat, including the western small-footed myotis (Myotis ciliolabrum), long- eared myotis (M. evotis), fringed myotis (M. thysanodes), long-legged myotis (M. volans), little brown bat (M. lucifugus), big brown bat (Eptesicus fuscus), eastern red bat (Lasiurus borealis), hoary bat (L. cinereus), and silver-haired bat (Lasionycteris noctivagans). Other species that typically use non-tree roosts but forage in forests and woodlands include Townsend’s big-eared bat (Corynorhinus townsendii), pallid bat (Antrozous pallidus), spotted bat (Euderma maculatum), Allen’s lappet-browed bat (Idionycteris phyllotis), canyon bat (Parastrellus hesperus), California myotis (M. californicus), and Yuma myotis (M. yumanensis). The big free-tailed bat (Nyctinomops macrotis) and Brazilian free-tailed bat (Tadarida brasiliensis) are known to forage above forests and woodlands in Colorado, Tree snag used as a maternity roost by but their distribution is restricted to warmer regions of the bats. Photo by D. Neubaum. state and driven by availability of high cliffs or large caves/mines for roosting. Several species do not occur at high elevations, others do not occur at low

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elevations, and some may be found in every forest type in the state. See the Introduction and Species Accounts for more details for species occurrence and habitat needs.

HOW BATS USE FORESTS AND WOODLANDS

Four ecological factors are important in shaping habitat suitability for bats in forests: characteristics and abundance of roost sites, amount of clutter, availability of water, and availability of prey (Hayes and Loeb 2007).

ROOSTS During the active season in Colorado (i.e., spring, summer, and fall), forest-dwelling bats can be found roosting in a variety of locations, including live trees, snags, and non-tree sites (e.g., caves, mines, rock crevices, bridges, buildings). These sites may be used by females with non-volant young, colonies of adults and juveniles, or single bats. Some species are strongly colonial or solitary roosters, and others are more flexible in their roosting habits. Bats roost in the crevices and cavities of live trees and snags, under exfoliating bark, and in the foliage of live trees. Hoary bats, red bats, and sometimes silver-haired bats will roost on the trunk or in the foliage of trees where their thick camouflaged coats help protect them from weather and predators. In addition to the natural folds and crevices of bark and branches, lightning strikes, fungal growth, fire scars, insect attacks, and broken tops and branches are all Bat roost under sloughing potential sources of decay that can make trees suitable roost sites for bark of pinyon pine snag. many species. In general, larger trees and snags provide more roosting Photo by D. Neubaum. surface and persist on the landscape longer than smaller trees, enabling them be reused for several years. Snags in middle decay classes are the most useful because they have more loose bark and cavities than those in very early or late decay classes. One highly suitable snag can house hundreds of bats and be very important to the local bat population (Taylor 2006; Hayes and Loeb 2007).

Factors such as roost microsite conditions and availability of alternate sites affect roost selection. Optimal thermal conditions at roosts vary by bat species, sex, reproductive status, age, and with the weather and time of year. Thermal and humidity conditions of potential roost trees and snags are affected by the surrounding forest and topographic position; ambient temperature, humidity, shade, sun, and wind exposure are all important factors affecting suitability of roost sites within a stand. Tree snag used as a bat Clumps of snags, or stands with higher snag densities, provide more roost. Photo by K. Navo.

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options for roost-switching and create roost space for bat colonies that may not all fit in one snag. Individuals may also frequently switch to a different roost tree daily or every few days. The same collection of trees may be reused repeatedly during the summer and between years, or individuals may continually find new roosts. Due to the ephemeral nature of tree and snag roosts, and the variety of thermal requirements within bat communities, forest management should allow for

Exit point from a bat roost in a juniper a diversity of roost trees and snags situated in a variety of tree snag. Photo by D. Neubaum. topographic and ecological settings to meet bat habitat needs across the seasons in perpetuity (Willis et al. 2006; Hayes and Loeb 2007; Chung-MacCoubrey unpublished).

Forest structure and juxtaposition around non-tree roosts (e.g., rocks, cliffs, caves, mines, bridges, and buildings) may have an influence on roost suitability for different bats, but specific effects are poorly understood (Hayes and Loeb 2007). Some species commonly select day roosts in non-tree sites despite availability of trees and snags in or near their foraging areas (Rabe et al. 1998; Ives et al. 2006; O’Shea et al. 2011; Schorr and Siemers 2013). Others may choose rock and cliff roosts where those resources are available, but will use trees and snags occasionally where rocks and cliffs are limited. This situation seems especially important in pinyon-juniper woodlands (Chung-MacCoubrey 2003; Siders and Jolly 2009; Solvesky and Chambers 2009; Snider et al. 2013).

CLUTTER The amount and size of obstacles a bat must detect and avoid in a given area is referred to as clutter. The space within a dense forest canopy is highly cluttered, whereas the space in a meadow, over a lake, or above the forest canopy is uncluttered. Within a forest, the degree of clutter varies with the density of trees and shrubs in the overstory and understory. Bat species differ in body size and wing shape, which affect their ability to maneuver in cluttered environments. Those with small bodies and low wing loading are able to exploit more cluttered habitats, whereas those with larger bodies and high wing loads are less tolerant of highly cluttered habitats (Hayes and Loeb 2007). Echolocation calls can also differ among species, with some calls better suited to cluttered environments and others suited to open environments (Schnitzler and Kalko 2001). However, most bats are able to use a range of open and cluttered environments. Bats frequently use edge habitat for commuting and foraging, and will target prey according to the species’ clutter tolerance and foraging strategy (e.g., gleaning or aerial hawking). Some species focus their foraging efforts in open areas within a few meters of the forest edge, others forage further out into the open or above the canopy, and still others remain primarily within the more dense forest (Jantzen and Fenton 2013). Thus, the ratio and arrangement of trees and openings on the landscape will influence the assemblage of bats in any given area. Natural disturbances and forest management activities that alter tree density and forest structure influence the degree of vegetation clutter and the bat community in turn.

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WATER Aquatic habitats play a critical role in bat ecology, as both a source of drinking water and insect prey. They are particularly important in arid environments, where water can be a limiting resource influencing the presence of bats. Active insectivorous bats have relatively high rates of evaporative water loss and consequently require surface water, which they consume in flight, to maintain their internal water balance (Hayes and Loeb 2007). Lactation can further increase drinking water requirements of reproductive females (Adams and Hayes 2008), and overall productive output of a population can be negatively affected in part by drought (Adams 2010). Riparian areas and open surface water are also important foraging areas where insect densities are often higher and insect communities are different than surrounding uplands (Bell 1980; Fukui et al. 2006). In densely forested landscapes, streams and lakes can provide open commuting paths, and in arid rangelands the cottonwood forests associated with surface water can provide the only tree and snag roosts for several miles (see section V. Rangeland Management Practices).

Not all surface water is equally beneficial to bats; a site’s suitability is influenced by the presence of flat water, the amount of surface area, and the arrangement of overhanging clutter. The sound of rough water can interfere with echolocation, and the shape and movement of waves make it difficult for bats to safely get very close to the water surface. Large water sources with greater open surface area are useful for larger bats that can’t maneuver over small and/or cluttered water sources, whereas smaller bats can take advantage of smaller sites, even puddles. Artificial water impoundments (e.g., troughs and stock ponds) in upland habitats can provide valuable sources of drinking water in otherwise arid lands, but they likely contribute little to prey abundance and can be death traps if they don’t have a clear flight path, are filled with floating algae, or don’t have functional escape ramps (Hayes and Loeb 2007; Taylor and Tuttle 2007).

PREY Forest vegetation and aquatic habitats provide resources not only for bats, but habitat for insects that the bats prey on. Bats consume large quantities of many types of insects in the air, from foliage, and on the ground. Bat body size, dentition, call structure, and wing morphology all affect the type of prey a bat may select (e.g., gnats vs. June beetles vs. moths), and many species have flexible and overlapping diets. Insect species composition and abundance differ across forested landscapes and over time with changes in the vegetation cover, which in turn can affect forest bats. Natural and anthropogenic disturbances are expected to alter prey availability, but the specific differences are difficult to generalize and not fully understood (Hayes and Loeb 2007; Snider 2009). For example, converting forest or woodland to another cover type by fire or mechanical means may make prey more available to some species and less available to others, or generally less (or more) available to all bats. The type, timing, severity, and extent of disturbance (e.g., fire, insect outbreak, or mechanical tree removal) also likely play a role in prey availability. The effect of such changes on prey availability in all forest and woodland types is in need of further research. Although typically used sparingly in forested landscapes, pesticides sprayed to thwart

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insect infestations in green stands could be directly or indirectly deleterious to forest bats, especially those roosting in the foliage of sprayed trees.

FOREST MANAGEMENT CONSIDERATIONS

Forest and woodland conditions are affected by anthropogenic and natural disturbances, which vary widely in type and scale. Generally, a forested landscape with an adequate amount of heterogeneity in stand structure and species composition will provide the habitat components for roosting and foraging that are required to maintain a diverse bat community in forests. Forest and woodland management actions should be informed by the natural range of variability of each ecosystem. There are some key characteristics that should be considered for bats when designing projects that alter forest and woodland conditions.

PATCH SIZE AND STAND STRUCTURE Management actions should reference the natural range of variation within a specific forest ecosystem to derive appropriate stand structure and patch size. Given that, the extremes of very dense forest and vast treeless areas without shrubs or water are less useful to many forest bats than some intermediate mixture of trees and openings. The species composition of a bat community will adjust to the available habitat. Landscapes with more dense multi-layered forest will favor highly-maneuverable bats, whereas landscapes with lower tree density and/or a greater amount of open habitat next to forested habitat will favor those that can’t navigate highly cluttered spaces (Figure 4.1). Landscapes with a range of tree densities and ages in a heterogeneous distribution will likely meet the needs of the most forest bat species.

Figure 4.1. Aerial photos of Pike National Forest demonstrating different levels of dense, mixed and sparse forest clutter. The dense forest is a stand of Engelmann spruce and subalpine fir; the mixed forest is a mixture of ponderosa pine, Douglas-fir, and aspen forest 8 years after the Hayman fire where some trees survived and some became snags; the sparse forest is a stand of ponderosa pine. Photos provided by M. Painter.

SNAGS AS ROOST TREES Forest stands composed of mostly younger, smaller trees and no snags are less valuable for roosting than stands with larger live trees with some damage or deformity and more numerous and larger snags. Clumps and groups of snags within a stand may also be more useful than single snags. Exposed snags in

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the open or on the windward side of a hill are more likely to fall due to wind. Single live trees or snags isolated in the open are also less likely to be used as roost sites since they offer only modest shelter from the elements in comparison to a secure stand of trees. Larger-diameter snags and trees with some damage or deformity are more valuable as roost sites for most forest bats than smaller-diameter trees. These trees and snags may be taller than the surrounding canopy, but not always.

SURFACE WATER In most of Colorado’s forest ecosystems surface water does not need augmentation for bats. Good water quality and adequate flow is important not only for the bats to drink, but to support healthy aquatic insect populations and riparian areas. Bats in arid pinyon-juniper woodlands may benefit from constructed water sources. No matter where they are located, these resources must be kept safe for bats to access; otherwise they can become a significant cause of bat mortality (e.g., stuck on barbed wire, trapped in floating algae, or drowned without a sufficient escape ramp). See Taylor and Tuttle (2007) for a thorough description of waters for wildlife.

All of these habitat components work together and must be replaced over time, so land managers should plan into the future to ensure the continued presence of these forest and woodland features as stands age, are disturbed, and regenerate across the landscape. Each disturbance or management action, such as widespread natural disturbance, timber harvest, or wildfire fuel reduction, does not inherently pose a threat to all bats in forests and woodlands. However, care must be taken to ensure the type and degree of natural and anthropogenic disturbances across a landscape do not overwhelm the ability of bat communities to compensate and persist.

In this chapter we address three broad categories of issues for rock crevice and cavity roosting bats: Forest and woodland management actions; insect outbreaks, tree disease, and wildfire; and Fuel reduction, rangeland improvement, and ecosystem restoration.

FOREST AND WOODLAND MANAGEMENT ACTIONS IN COLORADO

Federal land accounts for 67 percent of all forest types in Colorado, 29 percent is under private ownership, and the remainder is divided between state and tribal lands. It is important to note that 80 percent of forested wetlands are privately owned, and approximately half of ponderosa pine, juniper woodlands, and mixed conifer forests are also privately owned and managed (Schrupp et al. 2000). There is some level of management consistency among federal land management agencies, but forest management actions on private lands vary widely depending on the land management goals of the individual owners.

Forests and woodlands are naturally dynamic, and various disturbances act at multiple spatial and temporal scales to change or maintain forest conditions. Individual trees and whole stands commonly die or are damaged by insects, disease, fire, windthrow, and drought, and then are recolonized when conditions are favorable. Bats are adapted to the dynamic nature of forest ecosystems, as well as the

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balance of disturbance and stability within a landscape. Humans remove both live and dead trees by cutting, burning, dozing, or drowning. In Colorado the primary forest and woodland management issues include insect outbreaks, wildfire, fuel reduction, salvage and timber sales, rangeland improvement, and ecosystem restoration. Forest removal for such things as reservoir expansion, infrastructure, and other development needs occur across the state, but are generally localized. In contrast to some forested landscapes in other parts of the US like the Pacific Northwest and southeastern states, intensively managed commercial forests are not currently a part of the Colorado landscape.

GOAL MANGE COLORADO’S DIVERSE FOREST RESOURCES TO PROMOTE STABLE OR INCREASING BAT POPULATIONS FOR THE SPECIES KNOWN TO USE THEM. Objective 1: Encourage public and private land managers to actively and objectively consider bats in management decisions that involve forests and woodlands.

Objective 2: Encourage all land managers to communicate and work cooperatively across ownership boundaries to promote positive bat habitat management over broad spatial scales.

Objective 3: Assess bat populations in Colorado forests to determine population trends and refine species’ ranges by participating in established national efforts such as NABat (Loeb et al. 2015) or developing state and local level designs.

MANAGEMENT RECOMMENDATIONS  Consider landscape-scale management of mature forests for bat populations when developing forest management plans.  Protect an adequate density of large diameter and/or tall snags and live trees with cavities within forest stands. Trees with the following characteristics should be favored for retention: loose bark, dead or broken tops, lightning strikes, natural cavities, or woodpecker cavities.  Provide snags in clumped or clustered patterns across the landscape in all forest types, to address frequent roost switching that occurs with many forest-dwelling bats. Avoid leaving potential roost trees isolated as individuals within large clearcut blocks.  If natural snag density and conditions are severely lacking across a large focal area where green trees are abundant, replacement snags may be created by girdling or topping a selection of large live trees. However, artificially created snags are less useful to bats because they do not readily develop the loose bark and cavity features that occur in trees that die naturally from pathogens or trauma.  Provide land managers with up-to-date information on bat ecology and management recommendations for incorporation into agency plans.  Provide county extension agents and the Colorado State Forest Service information to assist private landowners with the protection and development of roost trees. Make private

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landowners aware of the value of snags and live cavity trees. Where possible, roost trees should not be removed if private lands must be cleared for development.

RESEARCH NEEDS

 Identify the timing of seasonal behaviors (i.e., hibernation, migration, reproductive stages) across the range of elevations and latitudes in Colorado for the various bat species that reside in or migrate through the state.  Collect basic data on bat activity in higher-elevation forests like lodgepole pine, bristlecone pine, and spruce-fir. The abundance of higher-elevation/lower-latitude forests in the southern Rocky Mountains is considerably different than surrounding regions.  Determine relative importance of aspen to bats. Do bat communities differ in forests where aspen is a major component compared to stands with little to no aspen?  Characterize bat activity in the many configurations and locations of the state’s broadly defined forest and woodland types.  Tree mortality is an important process in any forest or woodland ecosystem, but how do the different types and scales of tree mortality events compare in terms of bat activity and community responses? Consider natural and anthropogenic disturbances that result in tree mortality or removal. Are there thresholds for one event or an accumulation of events in a given landscape?  Investigate bat habitat use and the relationship of forest/woodland structure near non-tree roost sites such as urban areas or rock crevices, particularly for species that use both.  Conduct targeted observations to determine the extent of eastern red bat occurrence in the state; consider historic trends and the importance of riparian forests and woodlands in relation to the species.

INSECT OUTBREAKS, TREE DISEASES, AND WILDFIRE

In Colorado forests, fire, insects, and disease are among the major disturbance agents for changing forest composition and structure at both fine and broad scales. Insects such as wood borers, defoliators, and bark beetles typically exist at low levels, but can occasionally form significant outbreaks that can quickly cause widespread tree mortality (RMRFHP 2010). Since the late 1990’s, native bark beetle outbreaks in conifer forests and woodlands have been observed on a broad scale in the state, and the effects on bats are largely unknown. The adult beetles in flight may be an opportunistic source of prey for forest bats (similar to outbreaks of spruce budworm larvae; see Wilson and Barclay 2006), but their overall dietary significance is likely minimal. Disease and environmental stressors are also causing widespread decline of many aspen stands in Colorado (Worrall et al. 2010; Marchetti et al. 2011), which could alter bat foraging conditions and roosting habitat. After a severe insect or disease outbreak has passed and a forest stand is composed of mostly dead trees, the effects on insect and bat populations have not been thoroughly studied. Some land managers may choose to salvage dead trees, which is an additional factor of disturbance that should be investigated as it pertains to bats. After trees have died

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or been removed there are numerous possible stand regeneration outcomes that would influence bat habitat suitability and bat communities. The stand may be more accessible to clutter-intolerant bats, roost sites may temporarily be unlimited or eliminated, the bat community could switch to insects that respond to a rejuvenated understory and aspen regeneration, or overall prey availability could drop and cause bats to forage or roost elsewhere. Further study is needed to validate these possibilities.

Like insects and disease, fire is a natural process that most forests in Colorado evolved with. However, massive high-severity wildfires appear to be occurring more often and have become a concern to forest managers and residents in the state (e.g., 2000 Bircher Fire, 2002 Hayman Fire, 2002 Mount Zirkel Complex, 2012 High Park Fire, 2013 Black Forest Fire, 2013 West Fork Complex; Makings 2013). Researchers are beginning to investigate the effects of forest fire on bats, and so far the results appear to be mixed. Some studies have found bats to Large wildfires are capable of altering selectively forage and/or roost in burned areas (e.g., landscapes used by bats quickly. Wildfire has burned 73% of the pinyon-juniper woodland Lacki et al. 2009, Buchalski et al. 2013), while others on Mesa Verde in the last two decades alone. found bats foraging away from burned areas (e.g., Photo by D. Neubaum. Chambers and Saunders 2013, Snider et al. 2013). Fires may also remove important vegetation that releases large amounts of sediment which may inundate small water sources. O’Shea et al. (2011) found that the abundance of some species may have been altered in post fire surveys of Mesa Verde National Park due to the loss of ephemeral water sources from siltation. Other studies in Colorado have shown the importance of ephemeral water sources for a number of bat species and suggest that climate change and wildfire may threaten these resources (Adams et al. 2003; Neubaum 2017). Some fires may be beneficial for roosting or foraging, but not both. Like insect- and disease-killed stands, land managers may choose to salvage stands heavily impacted by fire. Fire severity, extent, forest type, and post-fire vegetation and management responses are all interacting factors that likely influence post-fire habitat suitability and bat communities.

GOAL MANAGE FOREST AND WOODLAND LANDSCAPES IN A MANNER THAT PROMOTES DYNAMIC, RESILIENT SYSTEMS THAT CONTINUE TO PROVIDE FORAGING AND ROOSTING HABITAT FOR BATS AFTER LARGE SCALE ALTERATION FROM DISEASE AND WILDFIRE HAS OCCURRED. Objective 1: Utilize long-term monitoring of bat use in forests and woodlands heavily altered by disease, insects, or wildfire to document the subsequent decline or rebound of populations, and the timelines on which they act to identify trends and inform future management decisions.

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MANAGEMENT RECOMMENDATIONS  Develop management plans with bat species in mind that consider multi-district landscape scales that account for landscape-scale disturbances.  Restore fire to forest stands to meet management objectives. Periodic low intensity burning in some forest systems could help maintain a more open understory and reduce clutter that impedes bat flight. Incorporate snag protection measures within burn plans.

RESEARCH NEEDS

 Investigate how bat populations are impacted pre and post large scale forest replacement events caused by insect outbreaks or wildfires.  Investigate bat population responses to timber salvage in comparison to non-salvaged stands that have been severely impacted by insects or fire.

FUEL REDUCTION, RANGELAND IMPROVEMENT, AND ECOSYSTEM RESTORATION

Land managers in Colorado intentionally manipulate forests and woodlands to meet a variety of goals (e.g., reduce fire hazard, ecosystem restoration, improve grazing opportunities, or timber sales), but most goals are accomplished with similar tools. Generally they include prescribed fire, tree removal with heavy equipment or chainsaws, and tree planting. Tree planting is not typically considered an issue for bat habitat management and will not be addressed further. More frequently, management questions involve the specifics of removing trees in bat habitat. Tree removal techniques differ among forest types, which may or may not have beneficial results for bat habitat. In lower montane forests like ponderosa pine, Douglas-fir, and mixed conifer, stands are cut or masticated to meet fuel reduction and ecosystem restoration goals. These mechanically treated areas may be thinned by size class and/or removed by group selection; often a more desirable species (e.g., ponderosa pine) is favored for retention. Prescribed fire is also used to maintain lower tree densities and rejuvenate the herbaceous understory. In upper montane and subalpine forests like lodgepole pine and spruce-fir, stands are more often cut by group selection or in larger patches that can cover tens or hundreds of acres, which also reduce fuel loads and can mimic some aspects of natural fire disturbances. In some locations, conifer stands are cut for merchantable timber or biomass production. Aspen are frequently favored for retention to enhance biodiversity, but some stands may be cut specifically for aspen logs or to encourage regeneration if the stand is deemed too decadent to persist without disturbance. At lower elevations, pinyon pine and juniper trees are removed singly or in patches by mulching, cutting, or burning to restore grassland and shrubland habitats for wildlife like sage grouse, pronghorn, and mule deer; to enhance growth of herbaceous and shrubby forage for livestock; and specifically for firewood sales.

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GOAL ENABLE HABITAT MANAGEMENT THAT PROMOTES BAT OCCUPANCY AND COMMUNITY DIVERSITY IN FORESTS AND WOODLANDS WHERE APPROPRIATE. Objective 1: Utilize forest management practices that promote or mimic natural forest disturbance regimes, both temporally and spatially.

Objective 2: Focus research activities on bat habitat issues that are widespread within, or particular to forest and woodland types of Colorado.

MANAGEMENT RECOMMENDATIONS  Encourage native tree species diversity within and among stands, where appropriate. Diverse stands support a wider variety of insect species, and are less susceptible to widespread insect and disease outbreaks.  Stagger harvest and fuels treatments through time across the landscape, and apply prescriptions that are informed by the natural disturbance regime of the local and desired forest type.  Plan for future bat roosting habitat on the landscape by identifying large-diameter live trees to retain during harvest activities. These trees should be protected during subsequent harvest entries as well.  Develop firewood guidelines to ensure retention of adequate snag densities in fuelwood units.  For larger land parcels (i.e., tens of acres or more), develop forest management plans that promote an appropriate balance of open, cluttered, and edge habitat suitable for the variety of bat species that are expected to use the area.  Maintain edge habitat, areas where treatments are excluded, and riparian corridors to promote roosting and foraging opportunities.

RESEARCH NEEDS

 Monitor bat community responses to changes in forests and woodlands triggered by shifting climate conditions.  Monitor bat community responses to mechanical and/or prescribed fire management of forests and woodlands and compare to unmanipulated forests and woodlands.

LITERATURE CITED Adams, R. A. 2010. Bat reproduction declines when conditions mimic climate change projections for western North America. Ecology 91(8): 2437-2445. Adams, R. A. and M. A. Hayes. 2008. Water availability and successful lactation by bats as related to climate change in arid regions of western North America. Journal of Animal Ecology 77: 1115-1121.

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Adams, R. A., S. C. Pedersen, K. M. Thibault, J. Jadin, and B. Petru. 2003. Calcium as a limiting resource to insectivorous bats: can water holes provide a supplemental mineral source? Journal of Zoology 260:189-194. Bell, G. P. 1980. Habitat use and response to patches of prey by desert insectivorous bats. Canadian Journal of Zoology 58: 1876-1883. Buchalski, M. R., J. B. Fontaine, P. A. Heady III, J. P. Hayes, and W. F. Frick. 2013. Bat response to differing fire severity in mixed-conifer forest California, USA. PLoS ONE 8(3): e57884. doi:10.1371/journal.pone.0057884 Chambers, C. L. and E. Saunders. 2013. Bats in the burns: studying the impact of wildfires and climate change. Bats 31(4): 16-17. Chung-MacCoubrey, A. L. 2003. Monitoring long-term reuse of trees by bats in pinyon-juniper woodlands of New Mexico. Wildlife Society Bulletin 31(1): 73-79. Chung-MacCoubrey, A. L. Unpublished. Roost selection and resource partitioning among 3 Myotis species in pinyon-juniper woodlands: implications for research and management. Unpublished draft. USDA Forest Service, Rocky Mountain Research Station. Albuquerque, New Mexico. Fukui, D., M. Murakami, S. Nakano, and T. Aoi. 2006. Effect of emergent aquatic insects on bat foraging in a riparian forest. Journal of Animal Ecology 75(6): 1252-1258. Hayes, J. P. and S. C. Loeb. 2007. The influences of forest management on bats in North America. Pages 209-235 in Lacki, M. J., J. P. Hayes, and A. Kurta (eds.). 2007. Bats in forests: conservation and management. Johns Hopkins University Press, Baltimore, Maryland. Ives, R. R., R. E. Sherwin, J. Jeffers, S. L. Skalak, D. Dalton, and S. Wolf. 2006. Differential use of pinyon- juniper woodland habitat by Townsend’s big-eared bats (Corynorhinus townsendii) in Pershing County, Nevada. Bat Research News 47(4): 112. Jantzen, M. K. and M. B. Fenton. 2013. The depth of edge influence among insectivorous bats at forest- field interfaces. Canadian Journal of Zoology 91: 287-292. Lacki, M. J., D. R. Cox, L. E. Dodd, and M. B. Dickinson. 2009. Response of northern bats (Myotis septentrionalis) to prescribed fires in eastern Kentucky forests. Journal of Mammalogy 90(5): 1165- 1175. Loeb, S. C., T. J. Rodhouse, L. E. Ellison, C. L. Lausen, J. D. Reichard, K. M. Irvine, T. E. Ingersoll, J. T. H. Coleman, W. E. Thogmartin, J. R. Sauer, C. M. Francis, M. L. Bayless, T. R. Stanley, and D. H. Johnson. 2015. A plan for the North American Bat Monitoring Program (NABat). Makings, V. 2012. Colorado’s largest fires, ranked by acres burned. The Denver Post, Denver. 11 June, 2012. Marchetti, S. B., J. J. Worrall, and T. Eager. 2011. Secondary insects and diseases contribute to sudden aspen decline in southwestern Colorado, USA. Canadian Journal of Forest Research 41: 2315-2325. Neubaum, D. J. 2017. Bat composition and roosting habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 to 2016. Colorado Parks and Wildlife. Grand Junction, CO.

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O’Shea, T. J., P. M. Cryan, E. A. Snider, E. W. Valdez, L. E. Ellison, and D. J. Neubaum. 2011. Bats of Mesa Verde National Park, Colorado: composition, reproduction, and roosting habits. Monographs of the Western North American Naturalist 5: 1-19. Rabe, M. J., M. S. Siders, R. Miller, and T. K. Snow. 1998. Long foraging distance for a spotted bat (Euderma maculatum) in northern Arizona. Southwestern Naturalist 43(2): 266-269. Schnitzler, H. and E. K. V. Kalko. 2001. Echolocation by insect-eating bats. BioScience 51(7): 557-569. Schorr, R. A. and J. L. Siemers. 2013. Characteristics of roosts of male pallid bats (Antrozous pallidus) in southeastern Colorado. Southwestern Naturalist 58(4): 470-474. Schrupp, D.L., W.A. Reiners, T.G. Thompson, L.E. O’Brien, J.A. Kindler, M.B. Wunder, J.F. Lowsky, J.C. Buoy, L. Satcowitz, A.L. Cade, J.D. Stark, K.L. Driese, T.W. Owens, S.J. Russo, and F. D’Erchia. 2000. Colorado Gap Analysis Program: A Geographic Approach to Planning for Biological Diversity - Final Report, USGS Biological Resources Division, Gap Analysis Program and Colorado Division of Wildlife, Denver, CO. Siders, M. S. and W. Jolley. 2009. Roost sites of Allen’s lappet-browed bats (Idionycteris phyllotis). Southwestern Naturalist 54(2): 201-203. Snider, E. A. 2009. Post-fire insect communities and roost selection by western long-eared myotis (Myotis evotis) in Mesa Verde National Park, Colorado. Thesis, Colorado State University, Fort Collins. 106 pages. Snider, E. A., P. M. Cryan, and K. R. Wilson. 2013. Roost selection by western long-eared myotis (Myotis evotis) in burned and unburned piñon-juniper woodlands of southwestern Colorado. Journal of Mammalogy 94(3): 640-649. Solvesky, B. G. and C. L. Chambers. 2009. Roosts of Allen’s lappet-browed bat in northern Arizona. Journal of Wildlife Management 73(5): 677-682. Taylor, D. A. R. 2006. Forest management and bats. A resource guide for land managers from. Bat Conservation International, Austin, Texas. Taylor, D. A. R. and M. D. Tuttle. 2007. Water for wildlife: a handbook for ranchers and range managers. Bat Conservation International, Austin, Texas. Rocky Mountain Region, Forest Health Protection. (RMRFHP). 2010. A field guide to diseases and insects of the Rocky Mountain Region. Gen. Tech. Rep. RMRS-GTR-241, Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 336 p. Willis, C. K. R., C. M. Voss, and R. M. Brigham. 2006. Roost selection by forest-living female big brown bats (Eptesicus fuscus). Journal of Mammalogy 87(2): 345-350. Wilson, J. M. and R. M. R. Barclay. 2006. Consumption of caterpillars by bats during an outbreak of western spruce budworm. American Midland Naturalist 155(1): 244-249. Worrall, J. J., S. B. Marchetti, L. Egeland, R. A. Mask, T. Eager, and B. Howell. 2010. Effects and etiology of sudden aspen decline in southwestern Colorado, USA. Forest Ecology and Management 260: 638- 648.

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V. RANGELAND MANAGEMENT PRACTICES

By Robert A. Schorr and Melissa S. Siders

Rangelands are natural communities dominated by grasses, forbs, and shrubs that are typically uncultivated and sustain grazing and browsing animals (Holechek et al. 2010). Rangeland management is the manipulation of rangeland components to obtain the optimum combination of goods and services for society on a sustained basis and is driven by 2 major principles: 1. Protection and enhancement of the soil and vegetation complex; and 2. Maintaining or improving the output of consumable range products (Holechek et al. 2010). In Colorado, approximately 40% of the state is rangeland with much of it in the eastern plains Shortgrass Prairie Ecoregion and the western parts of the state within the Colorado Plateau, Utah High Plateau, and Wyoming Basins ecoregions (see Introduction chapter; TNC 1999). An estimated 47.5 million acres of Colorado is grazed, with 22 million acres managed by federal agencies (Mitchell 1993).

Bats use rangelands for many life history needs, including feeding, drinking, roosting, and rearing young (Armstrong et al. 2011). Because some bat species frequently use rangelands as roosting and foraging habitat (Chung-MacConbrey 1996), there are several major rangeland management issues that have relevance for bat conservation. The issues addressed in this chapter include, riparian vegetation management, vegetation structure of pinyon-juniper forests and Mist nets set over stock pond utilized as a water sagebrush rangelands, pesticide use, and source by bats. Photo by D. Neubaum. conservation of drinking sites. These practices can impact the health of individuals and alter the availability and quality of water resources, prey production, and roosting habitats. There are additional range management issues that are likely to impact bats and bat populations, including abandon mine management, oil and gas development, and wind energy development, which are addressed in other sections of this Conservation Plan (see chapters I. Mining Issues and VIII. Energy Development).

We address the following four categories of issues resulting from rangeland management practices in Colorado: loss and degradation of riparian habitat associated with feeding and drinking resources; loss of vegetative structure in pinyon-juniper and sagebrush rangelands; impacts from pesticide and herbicide spraying; and alteration of availability and quality of water sources.

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LOSS AND DEGRADATION OF RIPARIAN HABITAT

In arid regions like Colorado rangelands, the availability of water resources can influence bat distribution and habitat use (Williams et al. 2006; Ober and Hayes 2007; Razgour et al. 2010). Riparian habitats provide roosting, drinking and foraging habitat for bats, as well as breeding habitat for their prey (Grindal et al. 1999; Williams et al. 2006). Riparian areas are important resources because of the high diversity and density of insect prey and the availability of clean water (Fukui et al. 2006). Riparian areas provide important resources for foraging females because of nutrient requirements related to reproduction and lactation (Wilkinson and Barclay 1997; Grindal et al. 1999). The loss or degradation of these habitats, especially in xeric settings, may adversely affect bat populations using these sites. Riparian habitat may be compromised on rangelands because of disruption of hydrologic regimes via dams and water diversions, excessive grazing pressure that changes hydrology and vegetation structure, and increased recreation use at or near streams (Kauffman and Krueger 1984; Armour et al. 1991; Lee et al. 1997). Because riparian habitats in rangeland environs are vital to conservation for a suite of bat species (Calvert and Neiswenter 2012), it is important to proactively manage and conserve these habitats (Briggs 1996).

GOAL PRESERVE AND RESTORE RIPARIAN HABITATS THROUGH THE PROMOTION OF SOUND GRAZING AND RECREATION MANAGEMENT PRACTICES, RIPARIAN BUFFERS, AND CONSERVATION EASEMENTS. Objective 1: Implement grazing management practices to maintain or improve riparian habitats for foraging and flyways. There are various rangeland management techniques that can improve or maintain quality riparian habitats (Kauffman et al. 1997; Holechek et al. 2010). Because excessive grazing pressure can compact soil, change hydrologic regimes, increase surface runoff, alter vegetation structure, and preclude some wildlife species (Warren et al. 1986; Sedgewick and Knopf 1987; Schulz and Leininger 1990; Giuliano and Homyack 2004), it is important to manage stocking rates that maintain natural rainfall infiltration, sedimentation, and vegetative structure for bat habitat. The Grazing Response Index is a helpful metric for assessing the impacts of grazing by focusing on the frequency of grazing, the intensity of the grazing pressure, and the amount of time allowed for plants to regenerate after grazing (Reed et al. 1999).

Objective 2: Implement recreation management that minimizes impacts to riparian systems. Similar to some of the riparian habitat impacts from grazing, recreation can impact riparian zones negatively by compacting soils, reducing vegetative cover, reducing infiltration rates, reducing soil organic matter, and increasing soil density (Johnson and Carothers 1982). Because the severity of recreational impacts can depend on the vegetation type and intensity, scale, and frequency of disturbance, it is recommended that land managers identify the vegetation types and riparian conditions that are most susceptible to recreation impacts, and then concentrate recreational activity in areas least impacted (Johnson and Carothers 1982). Additionally, discouraging human

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activity that impacts animal behavior patterns can minimize recreation impacts (Johnson and Carothers 1982). Most recreation impact assessments for bats have focused on cave visitation (see chapter II. Cave Management Practices; Boyle and Samson 1985), but recreation around riparian zones that impacts the vegetation, hydrology, or nocturnal behavior of bats can be detrimental for bat conservation.

Objective 3: Maintain riparian habitat in a manner that will encourage the restoration of native riparian species and historic hydrologic regimes. Dams and water diversions can greatly alter the hydrology and riparian habitats along the affected rivers (Nilsson and Berggren 2000; Anderson et al. 2007). Riparian habitats and waterways are invaluable resources for rangeland bats, and it is likely that modified river systems are unable to provide the roosting and feeding requirements needed by some western bats (Holloway and Barclay 2000). It is important to contrast bat habitat and resources along altered waterways and natural waterways, as has been done for other wildlife species (Breck et al. 2001). Such comparisons might elucidate how dams and water diversions create or eliminate habitat for bats.

Objective 4: Substantiate the importance of cottonwood galleries and other riparian ecosystems for foraging, roosting and migration in Colorado. Riparian cottonwood galleries near rangeland systems are valuable habitat for bats (Holloway and Barclay 2000; Swier 2003; Calvert and Neiswenter 2012), and given how water flow alterations can degrade riparian cottonwood forests (Rood et al. 2003), it is valuable to accurately assess the importance of cottonwood galleries to migratory and resident bat populations.

Objective 5: Support the establishment of conservation easements at properties that have intact riparian ecosystems in rangelands. There are financial and ecological advantages to conserving natural habitats, such as riparian zones, before they have undergone alteration (Balmford et al. 2002). In those areas where native riparian systems are intact, support efforts by local and regional conservation organizations to enter into easement agreements that maintain such habitats.

MANAGEMENT RECOMMENDATIONS  Implement steps to maintain or improve riparian and wetland habitat on rangelands systems. This would include restricting grazing and recreation access to riparian areas that show degradation (Kauffman et al. 1997), conducting restoration efforts to return degraded riparian systems to native conditions, restoring waterways to native flow regimes that create quality bat habitat, and maintaining stands of native cottonwood galleries along waterways (Poff et al. 1997, Wyman 2006).  Restore riparian habitats and the species they support by maintaining or introducing beaver (Castor Canadensis; McKinstry et al. 2007). Beaver are valuable creators of feeding habitat for bats because they create wetlands that are conducive for insect prey populations (Nummi et al. 2011). In riparian areas, dormant or growing season livestock grazing utilization should not

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exceed an average of 30% use on the native woody riparian species or 50% on herbaceous species (Mosley et al. 1999; Holechek et al. 2010).  Utilize existing resources, such as the various habitat conservation programs through the Natural Resources Conservation Service (Wetland Reserve Program; www.nrcs.usda.gov) and Colorado Parks and Wildlife (Wetland Wildlife Conservation Program; www.cpw.state.co.us) in order to facilitate and support mitigation of degraded riparian areas.

RESEARCH NEEDS

 Investigate the importance of riparian habitats on rangelands by assessing bat activity in these areas.  Investigate the impacts of exotic riparian species, such as salt-cedar (Tamarix ramosissima) and Russian-olive (Elaeagnus angustifolia), on insect communities and bat activity in riparian areas.  Investigate differences in bat habitat and resources between grazed and ungrazed or restored systems.

LOSS OF VEGETATIVE STRUCTURE IN PINYON-JUNIPER AND SAGEBRUSH RANGELANDS

A host of Colorado bats use pinyon-juniper forests and sagebrush shrublands for foraging and roosting (Armstrong et al. 2011). In an effort to restore some grassland systems, or increase rangeland or agricultural acreage, sagebrush and pinyon-juniper forests have been cleared using various methods (Evans 1988; Miller et al. 2000). Additionally, the sagebrush ecosystem is one of the most imperiled in the U.S. (Thompson 2007). The sagebrush steppe once occupied large expanses of the western U.S., but has been converted to conifer woodlands, exotic annual and introduced grasslands, and croplands, and is being degraded and fragmented by anthropogenic development (Davies et al. 2011). Conversion of pinyon-juniper and sagebrush lands can have ramifications for the nongame wildlife and wildlife habitat that rely on these systems (O’Meara et al. 1981; Baker 2006; Redmond et al. 2013). The pinyon-juniper and sagebrush habitats comprises only 7% of the Colorado landscape, yet provides the highest bat species diversity of all habitat types in the state (Armstrong et al. 2011). Bats forage and roost in pinyon- juniper forests and sagebrush steppe (Gitzen et al. 2002; Chung-MacCoubrey 2003; Snider et al. 2013) and conversion of these native systems via fire, fire suppression, mechanical manipulation, chemical control, and grazing can lead to a loss of vegetative structure that may impact bats (see chapter IV. Forest and Woodland Management Practices). Native, healthy sagebrush habitats provide essential insect prey for other wildlife species (Connelly et al. 2000), so it is likely that alterations to these habitats will impact bat insect prey abundance and diversity, which can alter bat behavior, diversity, and population health. Even habitat alterations to benefit rare species, such as reducing pinyon-juniper overstory to increase sagebrush cover and herbaceous understories for Gunnison sage grouse (Centrocercus minimus), can have unexpected impacts on other non-game species (Lukacs et al. 2015).

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GOAL LIMIT LARGE-SCALE DECLINES IN ROOSTING AND FEEDING HABITATS IN PINYON-JUNIPER FORESTS AND SAGEBRUSH LANDSCAPES BY LIMITING CONVERSION TO GRASSLANDS. Objective 1: Promote awareness of the importance of shrublands and pinyon-juniper habitats to the roosting ecology and feeding behavior of bats with management agencies and landowners. Encourage vegetation and/or seral stage restoration projects appropriate to the scale of the local ecological sites (Natural Resources Conservation Service Ecological Site Description, www.nrcs.usda.gov).

Objective 2: Provide information and recommendations to management agencies during major planning efforts to incorporate the need for diversity of vegetative structure in pinyon-juniper and shrub-steppe habitats.

MANAGEMENT RECOMMENDATIONS  Consult the standards regarding vegetation treatments used in the Species Conservation Assessment and Conservation Strategy for the Townsend’s big-eared bat (Corynorhinus townsendii; Pierson et al. 1999). These standards recommend caution when conducting prescribed burning or vegetative alteration in shrub-steppe or pinyon-juniper habitats “within a 1.5 mile radius of Townsend’s big-eared bat roost sites” or “within the 0.5 mile radius of Townsend’s big-eared bats roost sites, no more than half of the forested habitat can be subjected to prescribed burning per decade, and only at a time when the roost is not occupied”. Apply this same consideration to lands where colonies of bats are of conservation concern.  Maintain expanses of pinyon-juniper and sagebrush lands to provide habitat for the bats that use these systems.

RESEARCH NEEDS

 Investigate bat use, diversity and abundance in pinyon-juniper and sagebrush systems at various seral stages in Colorado.  Investigate the scale and patterns of rangeland vegetation alterations that support viable bat populations.

IMPACTS FROM PESTICIDE SPRAYING

Insects are known to be pests on rangeland systems (Watts et al. 1982), and bats contribute substantial financial benefit to agriculture by consuming large amounts of insects (Cleveland et al. 2006; Boyles et al. 2011). Most efforts to control insect pests have been aided by the use of insecticides; however there are known toxicity side-effects that can be detrimental to wildlife, including bats (Thies et al. 1996;

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O’Shea and Johnston 2009). The use of insecticides on rangelands and agricultural lands may cause direct poisoning of bats through the consumption of affected insects (Clark 1988). Bats are especially at risk of poisoning from large-scale use of insecticides because of their diet, high metabolic rates, high food intake, and high rates of fat mobilization during migration, hibernation, and lactation (Clark 1988; O’Shea and Clark 2002). Additionally, there are potential impacts to bat populations when insect-prey populations decrease.

GOAL LIMIT BROAD-SCALE USE OF INSECTICIDES ON RANGELANDS, AND PROMOTE AWARENESS OF POTENTIAL HARM TO BATS ON AGRICULTURAL LANDS THROUGH EDUCATIONAL EFFORTS, INPUT INTO LAND USE PLANNING EFFORTS, AND INTERACTION WITH FARMING COMMUNITIES.

MANAGEMENT RECOMMENDATIONS  Implement the standards regarding pesticide spraying in Pierson et al. (1999).  Identify all bat roosts within potential spray areas through surveys or literature review.  Intensify target insect sampling to identify specific outbreak species and times to decrease spray block size and intensity. Outside of established no-spray buffer zones, use application methods that minimize the potential for spray drift that affects non-target areas.  Consider utilizing a 2-mile radius no-spray buffer zone around all bat roost sites. Within a 10- mile radius of known bat roost sites, strip spray 0.25 mile strips (Pierson et al. 1999).  When available, utilize species-specific insect control measures (e.g., Nosema, a specific pesticide, or other specific biological control; Pierson et al. 1999).  Work with local, state, and federal agencies to obtain information on the impacts of pesticide use on bats.  Communicate the value of bat-based pest management, which saves the agricultural industry approximately $23 billion annually (Boyles et al. 2011).

RESEARCH NEEDS

 Investigate alternative pest control options that are safer to bats and other wildlife species.

CONSERVATION AND MANAGEMENT OF DRINKING WATER SOURCES

In the arid regions of Colorado rangelands, availability and access to open water for drinking and prey habitat may be a limiting resource for bat populations (Geluso and Geluso 2012; Hagen and Sabo 2012). The availability and quality of water has implications for habitat use and bat health (Rainho and Palmeirim 2011). For hydration and essential nutrients, water availability has been shown to influence the reproductive success in some bats (Kurta et al. 1990; McLean and Speakman 1999). During periods when water is scarce, bats can use artificial water resources for hydration, but some water resources can be traps for bats if they inadvertently fall into containment sites or may have obstacles that can

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make containment sites difficult to access (Tuttle et al. 2006; Taylor and Tuttle 2007; Korine et al. 2016).

Simple mitigation measures at stock tanks and water troughs can alleviate the threat of entrapment for bats (Taylor and Tuttle 2007). Additionally, some artificial water resources, such as water or effluent detention ponds at energy development facilities, can be detrimental to bats due to contamination (O’Shea et al. 2001, West 2011). For more information on this Stock tank utilized by bats as a water source. Photo by K. Navo. issue see chapter VI. Urban Development.

GOAL PROMOTE AVAILABILITY OF OPEN WATER FOR BATS IN ARID RANGELANDS AND IDENTIFY KEY DRINKING SITES FOR BAT COLONIES. PROTECT RANGELAND WATER RESOURCES, SUCH AS EPHEMERAL POOLS, SEEPS, AND SPRINGS, WHICH PROVIDE BAT RESOURCE NEEDS. WHEN LAKES, RESERVOIRS, RIVERS AND STREAMS ARE NOT NEARBY, SOME BATS MAY RELY ON SMALLER OR MORE-EPHEMERAL WATER SOURCES, SUCH AS STOCK TANKS, DRAINAGE DITCHES, SPRINGS, AND SEEPS (CHUNG-MACCOUBREY 1997). Objective 1: Promote awareness among land managers of the importance of open water for bats, and the need for bat accessibility at existing and planned water developments for other wildlife and livestock (Taylor and Tuttle 2007).

Objective 2: Develop and promote designs for stock tanks, water troughs, and guzzlers that allow easy access and egress by bats. Encourage the use and maintenance of wildlife escape ramps in stock tanks and water troughs.

Objective 3: Encourage land management agencies to maintain bat access to abandoned mines with associated water resources, such as pools from springs or rainfall, because they can be valuable water resources near roosting habitat.

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MANAGEMENT RECOMMENDATIONS  Implement a database that monitors the location of stock tanks/water troughs on public lands. Where feasible, advocate for continuity in maintaining water bodies that are accessible to bats in arid environments.

 Install and maintain escape ramps at troughs and other water structures.

 Avoid barbed-wire fencing near water features when Hoary bat caught on barbed-wire possible. fence. Photo by D. Neubaum. RESEARCH NEEDS

 Develop and test designs for wildlife guzzlers and troughs that allow easy use by bats.  Determine drinking water chemistry requirements of maternity colonies and identify and conserve water sources near these roosts, especially for Townsend’s big-eared bat and other species of concern.  Investigate bat dependence on ephemeral water sources, both natural and developed, in arid environments to understand how home ranges (and energy budgets) are altered with the availability of such water resources.  Investigate bat use of oil and gas development water impoundments to understand how their availability alters habitat use, how use of such resources may concentrate toxic materials in bat tissues, and if bat mortality occurs at such detention ponds.

LITERATURE CITED Anderson, D. C., D. J. Cooper, and K. Northcott. 2007. Dams, floodplain land use, and riparian forest conservation in the semiarid upper Colorado River Basin, USA. Environmental Management 40:453- 475. Armour, C. L., D. A. Duff, and W. Elmore. 1991. The effects of livestock grazing on riparian and stream ecosystems. Fisheries 16: 7-11. Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado, 2nd ed. University of Colorado Press, Boulder. Baker, W. L. 2006. Fire and restoration of sagebrush ecosystems. Wildlife Society Bulletin 34:177-185. Balmford, A., A. Bruner, P. Cooper, R. Costanza, S. Farber, R. E. Green, M. Jenkins, P. Jefferiss, V. Jessamy, J. Madden, K. Munro, N. Myers, S. Naeem, J. Paavola, M. Rayment, S. Rosendo, J. Roughgarden, K. Trumper, and R. K. Turner. 2002. Economic reasons for conserving wild nature. Science 297:950-953.

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Boyles, J. G., P. M. Cryan, G. F. McCracken, and T. H. Kunz. 2011. Economic importance of bats in agriculture. Science 332:41-42. Boyle, S. A., and F. B. Samson. 1985. Effects of nonconsumptive recreation on wildlife: a review. Wildlife Society Bulletin 13:110-116. Breck, S. W., K. R. Wilson, and D. C. Anderson. 2001. The demographic response of bank-dwelling beavers to flow regulation: a comparison on the Green and Yampa rivers. Canadian Journal of Zoology 79:1957-1964. Briggs, M. K. 1996. Riparian ecosystem recovery in arid lands: strategies and references. University of Arizona Press, Tucson. Calvert, A. W., and S. A. Neiswenter. 2012. Bats in riparian-restoration sites along the lower Colorado River, Arizona. Southwestern Naturalist 57:340-342. Chung-MacCoubrey, A. L. 1996. Grassland bats and land management in the Southwest. Pp 54-63 in Ecosystem disturbance and wildlife conservation in western grasslands: a symposium proceedings (D. Finch, ed.). USFS General Technical Report RM-GTR-285. Fort Collins, Colorado. Chung-MacCoubrey, A. L. 2003. Monitoring long-term reuse of trees by bats in pinyon-juniper woodlands of New Mexico. Wildlife Society Bulletin 31:73-79. Clark, D. R. 1988. How sensitive are bats to insecticide? Wildlife Society Bulletin 16:399-405. Cleveland, C. J., M. Betke, P. Federico, J. D. Frank, and T. G. Hallam. 2006. Economic value of pest control service provided by Brazilian free-tailed bats in south-central Texas. Frontiers in Ecology and the Environment 4:238-243. Connelly, J. W., M. A. Schroeder, A. R. Sands, and C. E. Braun. 2000. Guidelines to manage sage grouse populations and their habitats. Wildlife Society Bulletin 28:967-985. Davies, K. W., C. S. Boyd, J. L. Beck, J. D. Bates, T. J. Svejcar, and M. A. Gregg. 2011. Saving the sagebrush sea: an ecosystem conservation plan for big sagebrush plant communities. Biological Conservation 144:2573-2584. Evans, R. A. 1988. Management of pinyon-juniper woodlands. USDA Forest Service General Technical Report INT-249. Odgen, Utah. 34 pp. Fukui, D., M. Murakami, S. Nakano, and T. Aoi. 2006. Effect of emergent aquatic insects on bat foraging in a riparian forest. Journal of Animal Ecology 75:1252-1258. Geluso, K. N., and K. Geluso. 2012. Effects of environmental factors on capture rates of insectivorous bats, 1971-2005. Journal of Mammalogy 93:161-169. Gitzen, R. A., J. L. Erickson, and S. D. West. 2002. Bat activity and species occurrence on the Hanford Site in eastern Washington. Northwestern Naturalist 83:35-46. Grindal, S. D., J. L. Morissette, and R. M. Brigham. 1999. Concentration of bat activity in riparian habitats over an elevational gradient. Canadian Journal of Zoology 77:972-977. Guiliano, W. M., and J. D. Homyack. 2004. Short-term grazing exclusion effects on riparian small mammal communities. Journal of Range Management 57:346-350.

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Hagen, E. M., and J. L. Sabo. 2012. Influence of river drying and insect availability on bat activity along the San Pedro River, Arizona (USA). Journal of Arid Environments 84:1-8. Holechek, J. L., R. D. Pieper, and C. H. Herbel. 2010. Range Management: Principles and Practices, 6th edition. Prentice Hall, Upper Saddle River, New Jersey. Holloway, G. L., and R. M. R. Barclay. 2000. Importance of prairie riparian zones to bats in southeastern Alberta. Ecoscience 7:115-122. Johnson, R. R., and S. W. Carothers. 1982. Riparian habitat and recreation: interrelationships and impacts in the Southwest and Rocky Mountain Region. Eisenhower Consortium Bulletin 12. Eisenhower Consortium for Western Environmental Forestry. Fort Collins, Colorado. 31 pp. Lee, D. C., J. R. Sedell, B. E. Riemen, R. F. Thurow, and J. E. Williams. 1997. Broadscale assessment of aquatic species and habitats. In An Assessment of Ecosystem Components in the Interior Columbia Basin and Portions of the Klamath and Great Basins: Volume 1 (ed. T. M. Quigley). USFS-PNW-GTR- 405. Portland, Oregon. Lukacs, P. M., A. Seglund, and S. Boyle. 2015. Effects of Gunnison sage-grouse habitat treatment effort on associated avifauna and vegetation structure. Avian Conservation and Ecology 10:7. Kauffman, J. B., and W. C. Krueger. 1984. Livestock impacts on riparian ecosystems and streamside management implications: a review. Journal of Range Management 37:430-438. Kauffman, J. B., R. L. Beschta, N. Otting, and D. Lytjen. 1997. An ecological perspective of riparian and stream restoration in the western United States. Fisheries 22:12-24. Korine, C., R. A. Adams, D. Russo, M. Fisher-Phelps, and D. Jacobs. 2016. Bats and water: anthropogenic alterations threaten global bat populations. Pp 215-233 in Bats in the Antropocene: Conservation of Bats in a Changing World (C. C. Voigt and T. Kingston, eds). Springer International AG, Cham, Switzerland. Kurta, A., T. H. Kunz, and K. A. Nagy. 1990. Energetics and water flux of free-ranging big-brown bats (Eptesicus fuscus) during pregnancy and lactation. Journal of Mammalogy 71:59-65. McClean, J. A., and J. R. Speakman. 1999. Energy budgets of lactating and non-lactating reproductive brown long-eared bats (Plecotus auritus) suggest females use compensation in lactation. Functional Ecology 13:360-372. McKinstry, M. C., P. Caffrey, and S. H. Anderson. 2007. The importance of beaver to wetland habitats and waterfowl in Wyoming. Journal of American Water Resources Association 37:1571-1577. Miller, R. F., T. J. Svejcar, and J. A. Rose. 2000. Impacts of western juniper on plant community composition and structure. Journal of Range Management 53:574-585. Mitchell, J. E. 1993. The rangelands of Colorado. Rangelands 15:213-219. Mosley, J.C., P. S. Cook, A. J. Griffis, and J. O’Laughlin. 1999. Guidelines for managing cattle grazing in riparian areas to protect water quality: review of research and best management practices policy. Idaho Forest, Wildlife and Range Experiment Station, University of Idaho, Moscow, Idaho.

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Nilsson, C., and K. Berggren. 2000. Alterations of riparian ecosystems caused by river regulation. BioScience 50:783-792. Nummi, P., S. Kattainen, P. Ulander, and A. Hahtola. 2011. Bats benefit from beavers: a facultative link between aquatic and terrestrial food webs. Biodiversity Conservation 20:851-859. Ober, H. K., and J. P. Hayes. 2007. Influence of vegetation on bat use of riparian areas at multiple scales. Journal of Wildlife Management 72:396-404. O’Meara, T. E., J. B. Haufler, L. H. Stelter, and J. G. Nagy. 1981. Wildlife responses to chaining of pinyon- juniper woodlands. Journal of Wildlife Management 45:381-389. O'Shea, T. J., A. L. Everette, and L. E. Ellison. 2001. Cyclodiene insecticide, DDE, DDT, arsenic, and mercury contamination of big brown bats (Eptesicus fuscus) foraging at a Colorado superfund Site. Archives of Environmental Contamination & Toxicology 40:112-120. O’Shea, T. J., and D. R. Clark, Jr. 2002. An overview of contaminants and bats, with special reference to insecticides and the Indiana bat. Pp. 237-253 in The Indiana Bat: Biology and Management of an Endangered Species (A. Kurta and J. Kennedy, eds.). Bat Conservation International, Austin, Texas. O’Shea, T. J., and J. J. Johnston. 2009. Environmental contaminants and bats: investigating exposure and effects. Pp. 500-528 in Ecological and Behavioral Methods for the Study of Bats, 2nd edition (T. H. Kunz and S. Parsons, eds.). Johns Hopkins University Press, Baltimore, Maryland. Pierson, E. D., M. C. Wackenhut, J. S. Altenbach, P. Bradley, P. Call, D. L. Genter, C. E. Harris, B. L. Keller, B. Lengus, L. Lewis, B. Luce, K. W. Navo, J. M. Perkins, S. Smith, and L. Welch. 1999. Species conservation assessment and strategy for the Townsend’s big-eared bat (Corynorhinus townsendii townsendii and Corynorhinus townsendii pallescens). Idaho Department of Fish and Game, Boise, Idaho. Poff, N. L., J. D. Allan, M. B. Bain, J. R. Karr, K. L. Prestegaard, B. D. Richter, R. E. Sparks, and J. C. Stromberg. 1997. The natural flow regime: a paradigm for river conservation and restoration. BioScience 47:769-784). Rainho, A., and J. M. Palmeirim. 2011. The importance of distance to resources in the spatial modelling of bat foraging habitat. PLOS One 6:e19227. Razgour, O., C. Korine, and D. Saltz. 2010. Pond characteristics as determinants of species diversity and community composition in desert bats. Animal Conservation 13:505-513. Redmond, M. D., N. S. Cobb, M. E. Miller, and N. N. Barger. 2013. Long-term effects of chaining treatments on vegetation structure in pinon-juniper woodlands of the Colorado Plateau. Forest Ecology and Management 305:120-128. Reed, F., R. Roath, and D. Bradford. 1999. The grazing response index: a simple and effective method to evaluate grazing impacts. Rangelands 21:3-6. Rood, S. B., J. H. Braatne, and F. M. R. Hughes. 2003. Ecophysiology of riparian cottonwoods: stream flow dependency, water relations and restoration. Tree Physiology 23:1113-1124.

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Schulz, T. T., and W. C. Leininger. 1990. Differences in riparian vegetation between grazed areas and exclosures. Journal of Range Management 43:295-299. Sedgewick, J. A., and F. L. Knopf. 1987. Breeding bird response to cattle grazing on a cottonwood bottomland. Journal of Wildlife Management 51:230-237. Snider, E. A., P. M. Cryan, and K. R. Wilson. 2013. Roost selection by western long-eared myotis (Myotis evotis) burned and unburned pinon-juniper woodlands of southwestern Colorado. Journal of Mammalogy 94:640-649. Swier, V. J. 2003. Distribution, roost site selection and food habits of bats in eastern South Dakota. Master’s Thesis. South Dakota State University, Brookings, South Dakota. Taylor, D. A. R., and M. D. Tuttle. 2007. Water for wildlife: a handbook for ranchers and range managers. Bat Conservation International, Austin, Texas. Thompson, J. 2007. Sagebrush in western North America: habitats and species in jeopardy. Science Findings: 91. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p TNC (The Nature Conservancy). 1999. TNC Ecoregions and Divisions Map. Available at: http://maps.tnc.org/gis_data.html. Thies, M. L., K. Thies, and K. McBee. 1996. Organochloride pesticide accumulation and genotoxicity in Mexican free-tailed bats from Oklahoma and New Mexico. Archives of Environmental Contamination and Toxicology 30:178-187. Tuttle, S. R., C. L. Chambers, and T. C. Theimer. 2006. Potential effects of livestock water-trough modifications on bats in northern Arizona. Wildlife Society Bulletin34:602-608. Warren, S. D., T. L. Thurow, W. H. Blackburn, and N. E. Garza. 1986. The influence of livestock trampling under intensive rotation grazing on soil hydrologic characteristics. J. of Range Management 39:491- 495. Watts, J. G., E. W. Huddleston, and J. C. Owens. 1982. Rangeland entomolgy. Annual Review of Entomology 27:283-311. West, N. 2011. Monitoring bat use of oil pits in the Osage Oil Field. Unpublished report – Bureau of Land Management, High Plains District, Newcastle Field Office. Newcastle, Wyoming. Wilkinson, L. C., and R. M. R. Barclay. 1997. Differences in foraging behaviour of male and female big brown bats (Eptesicus fuscus) during the reproductive period. Ecoscience 4:279-285. Williams, J. A., M. J. O’Farrell, and B. R. Riddle. 2006. Habitat use by bats in a riparian corridor of the Mojave Desert in southern Nevada. Journal of Mammalogy 87:1145-1153. Wyman, S. 2006. Riparian area management: grazing management processes and strategies for riparian- wetland areas. Bureau of Land Management Technical Reference 1737-20. Prineville, Oregon.

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VI. URBAN DEVELOPMENT

By Amy C. Englert and Daniel J. Neubaum

The management of bats in the rapidly urbanizing West is becoming an increasingly important undertaking. Colorado’s population growth was second in the U.S. from 2014-2015, increasing by almost 100,000 people, with similar increases projected into the future (Garner 2016). The Front Range has been impacted the most, accounting for 96% of the growth between 2010 and 2015 (Fig. 6.1). Research on bat use of anthropogenic features clearly shows that the spread of urban environments is a multifaceted and complex issue with each bat species found in Colorado reacting differently to the associated factors.

Threats related to urban development include loss of foraging habitat, effects from pollution, and a negative image of bats due to roosting in urban structures. Bats using buildings, particularly large maternity colonies, may have undesirable effects, especially when guano accumulations create odors and stains, or become large enough to stress the structural integrity of building components such as ceiling supports and sheathing. Use of anthropogenic structures by bats also carries implications for public health as it increases the chances of interactions with people, particularly when animals become

Figure 6.1. Total population change in Colorado from 2010 – 2015. Colorado State Demography Office, 2016.

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sick. Conversely, Neubaum et al. (2007) found urban development may increase the number of potential roosts for Colorado bat species that commonly use anthropogenic structures such as the big brown bat (Eptesicus fuscus) and little brown myotis (Myotis lucifugus). Not surprisingly, the natural adaptations of different species help to determine how likely they may be to use urban environments. Bats that are adapted to cluttered environments generally do not become accustomed to urbanization as readily as faster-flying species that select open environments (Avila-Flores and Fenton 2005; Luck et al. 2013).

We address five categories of issues relating to urban development in Colorado: changes in urban habitats, roosting ecology of anthropogenic structures, foraging, pollution, and disease.

URBAN HABITAT

Urban landscapes differ from natural bat habitats in many obvious ways, but some habitat modifications have the potential to affect bat populations to a higher degree, including habitat fragmentation, artificial lights, and noise pollution. Roads and bridges may fragment habitat even in lightly developed areas. Bats have been shown to adjust their flight paths to avoid crossing roads, especially low-flying species (Bennett and Zurcher 2012; Berthinussen and Altringham 2012). Bats using urban areas may also be at a higher risk for motor vehicle collisions, which can be a significant source of bat mortality (Bennett and Zurcher 2012) and have been found to select roosts in areas with lower traffic densities (Neubaum et al. 2007). One study documented more bats turning away from roads where noise levels exceed 88 dB, but this disturbance threshold may differ among species (Bennett and Zurcher 2012). Noise pollution is more likely to be present in heavily urbanized areas than less developed suburban areas. Although studies of urban noise pollution impacts on bats are limited (Bennett and Zurcher 2012), a study in northwestern Colorado found that bats were less likely to use areas of oil and gas development due to noise pollution (Warner 2016). Greenbelts, urban parks, and other natural areas can provide good habitat and safe travel corridors for bat use, and are important considerations when planning new urban development. Artificial lights in urban environments have been shown to affect some species negatively, and others positively (Berthinussen and Altringham 2012; Williams 2012; Lewanzik and Voigt 2014).

GOAL MAKE URBAN AREAS MORE SUITABLE FOR SPECIES THAT ARE SENSITIVE TO THE PRESENCE OF ROADS, ARTIFICIAL LIGHT, AND NOISE POLLUTION. Objective 1: Partner with Colorado Department of Transportation (CDOT) and local transportation departments on issues regarding bat use of roads and bridges for roosting habitat and travel corridors.

Objective 2: Increase knowledge of baseline bat populations using urban and transitional areas.

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MANAGEMENT RECOMMENDATIONS  Construct structures to increase road permeability in areas near large urban bat colonies. These can include over or underpasses, or guidance systems (Altringham 2011).  Plant vegetation along roads as sound buffers near large urban bat colonies (Bennett and Zurcher 2012).  Promote “Dark Sky” practices.

RESEARCH NEEDS

 Determine which bat species are most susceptible to light and noise pollution.  Determine which bat species are most affected by road construction.  Determine the effectiveness of methods used to increase road permeability.  Determine the size needed for natural areas to benefit urban bat colonies.

URBAN ROOSTING ECOLOGY OF ANTHROPOGENIC STRUCTURES

The relationship between roosting ecology and urbanization is a complex one. Some species seem to benefit from new urban structures, in some cases actually preferring them to natural roosts (Lausen and Barclay 2006; Allen et al. 2010; O’Shea et al. 2010). Other species, like pallid bats (Antrozous pallidus), seem to be intolerant of urbanization (Miner and Stokes 2005). Tree-roosting bat species may be negatively impacted by urbanization because tree snags are likely to be removed for aesthetics or safety concerns (Duchamp and Swihart 2008). Conversely, urbanization of former grasslands and shrublands along the Front Range has resulted in the planting of more live trees which may benefit other bat species (Neubaum 2005). Bat populations may be impacted by the loss of roosting habitat through the modification and/or replacement of bridges (Keeley and Tuttle 1999) and the eviction and/or killing of bats roosting in houses and other buildings. Urban sprawl may increase roosting opportunities for those species which appear to accept the hazards of anthropogenic roost use in exchange for potential benefits such as warmer roost temperatures (Racey and Swift 1981; Neubaum et al. 2007).

Maternity roost in a building, and large guano pile in an attic. Photos by D. Neubaum.

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On the northern Front Range of Colorado Neubaum et al. (2007) documented big brown bats using a wide array of anthropogenic structures for maternity colonies including barns, houses, businesses, churches, schools, a stadium, and apartment buildings. The timing and extent of anthropogenic structure use may vary by species as well. Little brown myotis were shown to use buildings for short stints in late summer and early autumn as transition roosts once maternity colonies began to disperse (Neubaum 2018). Roosts in urban areas may put bats at a higher risk for predation by owls, human commensals like magpies, and domestic animals like cats (Van Horne 1983; Ancillotto et al. 2013). Disturbance of bat roosts in urban settings may negatively affect bat populations. For example, big brown bats were excluded from 30-35% of maternity roosts in anthropogenic structures that were studied over a 5 year period (Neubaum et al. 2007, O’Shea et al. 2011). No long-term effects on reproduction or survival were noted for the marked bats from the study, suggesting that this species can tolerate some level of disturbance. The need to exclude bats from anthropogenic structures may arise for a number of reasons, such as health concerns (e.g., roosts in schools and day care centers; O’Shea et al. 2011), remodeling efforts, or special management (e.g., roosts in historic buildings; Fagan et al. 2017). Use of anthropogenic structures outside of highly urbanized settings is not uncommon and presents owners with many of the same challenges noted above. Inconveniences to building owners or managers may reinforce negative stereotypes regarding bats as pests in the eyes of the general public.

GOAL PREVENT THE DECLINE OF BAT SPECIES ASSOCIATED WITH URBAN ROOSTS IN COLORADO, WHILE PROMOTING THE BENEFICIAL EFFECTS OF BATS LIVING IN URBAN AREAS AND PROPER TECHNIQUES FOR DEALING WITH SITUATIONS WHERE BATS BECOME A NUISANCE. Objective 1: Encourage use of humane exclusion methods that incorporate seasonal timing stipulations and suitable/safe exclusion materials.

Objective 2: Promote the use of properly constructed bat houses in urban settings to alleviate nuisance bat problems, control insect pests, and advance bat conservation.

Objective 3: Promote awareness of the implications of bats to human health in Colorado. Work with the Colorado Department of Public Health and Environment, the public school system, and others to reduce fear of bats, and educate on the proper approach to bat/human interactions.

MANAGEMENT RECOMMENDATIONS  Provide information to state, federal, and county pest control agencies, and to private companies regarding best management practices on excluding bats from houses, and encourage non-lethal techniques.  Promote the use of bat houses in urban settings with nuisance bat problems using designs and placement shown to be most effective (White 2004; Mering and Chambers 2014).  Promote exclusions rather than extermination if owners wish to remove bats. Encourage proper timing of exclusion work to coincide with when bats are not using the structures (generally

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 October – March for maternity colonies) to avoid entrapment of bats inside the roost. If exclusion work cannot wait until bats are gone for the season, suggest use of humane devices such as mesh netting or one-way doors that allow egress but not entrance.  Work with the Colorado Historical Society and others to promote the preservation of important bat roosts in historic buildings.  Work with CDOT and local transportation departments to make staff more aware of the relationship of bats and bridges, and to conserve roosts in those structures when opportunities develop.  Provide information to CDOT regarding bridge designs and Large Brazilian free-tailed bat modifications that are compatible with bats. colony using an overpass. Photo by D. Neubaum. RESEARCH NEEDS

 Obtain data on the use and importance of bridges in urban versus rural locations. Complete basic bridge surveys.  Research the roosting potential provided in new developments to determine if loss of historic roosts in old buildings and bridges is offset by new development. (See Williams and Brittingham 1997 and Neubaum et al. 2007 for opposing views on this topic.)  Determine if bat species that are roosting in Biologist inspecting a maternity roost under a bridge. Photo by J. Gore. urban settings are expanding their range or vacating natural historic habitat.  Determine if predation due to human commensals or feral/outside domestic cats is a large factor in urban bat mortality (Ancilloto et al. 2013).

URBAN FORAGING

Some bat species are able to successfully forage in urban developments, while others may have difficulty. This variability probably depends on the preferred type of insect, flight speed, maneuverability, and tolerance to artificial light by bats. For instance, Brazilian free-tailed bats (Tadarida brasiliensis) have been documented to be more active in lighted areas (Avila-Flores and Fenton 2005; Williams 2012). Larger urban colonies may create more foraging competition, resulting in bats that need to travel longer distances to forage effectively. This can lead to lower individual fitness,

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which is partially determined by body condition (Van Horne 1983). Everette et al. (2001) noted that big brown bats foraging at the Rocky Mountain Arsenal moved from 9.2–18.8 km back to houses in Denver where they roosted during the day. In Fort Collins this species averaged 5.9 km between maternity roosts and foraging areas with some individuals moving as far as 18 km a night (O’Shea et al. 2011). In both studies, big brown bats were leaving a highly urbanized setting to forage in adjacent natural areas and agricultural lands. Some green building practices, like “green roofs”, may increase bat foraging in dense urban landscapes (Pearce and Walters 2011). Additionally, open space, parks, and artificial water sources in urban environments have been shown to foster bat activity, and could increase survivability (Kurta and Teramino 1992; Everette et al. 2001). This is especially true with the loss of wetland habitat due to urbanization.

GOAL TO PROTECT AND AUGMENT AREAS THAT FOSTER GOOD FORAGING CONDITIONS FOR BATS. Objective 1: Promote acquisition of open spaces within and adjacent to urbanized areas that retain native plant and insect communities.

Objective 2: Restore native plants in natural areas and large parks to increase insect populations for bat species that are specialized feeders.

Objective 3: Work with other agencies to help maintain populations of native insects that are important parts of the food base for urban bats.

Objective 4: Work to conserve the quality and accessibility of urban water sources, which may provide important foraging and drinking sites, especially in the arid west.

Objective 5: Preserve and improve wetland habitat through land use planning.

MANAGEMENT RECOMMENDATIONS  Locate large urban colonies with the help of the public, and work with city governments to conserve and protect water resources in the immediate areas.  Work with current wetland conservation programs to protect wetland habitat, such as the Wetland Wildlife Conservation Program through Colorado Parks and Wildlife, and the Marsh Program through Ducks Unlimited, etc.  Promote the use of bat houses in urban wetland areas.

RESEARCH NEEDS

 Verify whether green roofs, gardens, and small parks in heavily urbanized areas are used by foraging bats.  Determine the degree to which bats use greenbelts, and whether they use them for roosting, foraging, commuting, and/or other purposes.

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 Expand current knowledge of the use of wetlands by bats in urban settings.  Document the benefits of insect control by bats in urban settings.

POLLUTION

As more pollution from point and nonpoint sources impact water and air quality in urban and agricultural areas, the question of how this may affect bat populations becomes more salient. Bats may be directly poisoned by water, air, or roost contaminants, but they may also be indirectly impacted by contamination of the insects they consume (O’Shea and Johnston 2009). Biomagnification of toxins can be a serious threat to bats due to their consumption of insects with high contamination levels, high levels of food intake, and long lifespans. This is especially true if the bat species in question has a high dependence on aquatic insects. In Colorado, O’Shea et al. (2001) found concentrations of several pesticides in carcasses, brains, stomach contents, and guano from big brown bats captured at the Rocky Mountain Arsenal National Wildlife Refuge adjacent to the city of Denver. Bats in that study showed higher contamination levels than other mammals tested at the site, suggesting that the chemicals could be concentrated in the food sources bats are selecting. The liberal use of insecticides and herbicides in both urban and agricultural areas can erode the prey base of bats. Wickramasinghe et al. (2004) documented that bats discern differing levels of insect abundance tied to use of chemicals and are subsequently more apt to forage over organic rather than conventional farms. Urban mosquito control efforts may be another method that introduces such chemicals to wetlands. Wastewater treatment plants can drastically change the composition of species in riverine habitats downstream (Pilosof et al. 2013). In a 2007 study, Kalcounis-Rueppell et al. reported that the complement of bat species foraging over rivers upstream and downstream from wastewater treatment plants was notably different, and hypothesized that this is due to the different populations of insects present due to eutrophication downstream of the treatment plants. A similar study by Vaughan et al. (1996) found that results varied depending on the species under consideration. Again, impacts of urbanization on bats are likely to vary by species so careful determination will be required to manage for all bats in an area.

GOAL DETERMINE THE EFFECTS OF AIR AND WATER POLLUTION ON URBAN BAT POPULATIONS, AND FORMULATE REALISTIC STRATEGIES FOR MITIGATION. Objective 1: Promote awareness of potential impacts to bat populations from urban pesticide spraying programs.

Objective 2: Work with local agencies to enact water quality standards and appropriate disposal of pollutants.

Objective 3: Test water quality and insect communities for bioaccumulation of residues at sites with a known or suspected history of contamination.

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MANAGEMENT RECOMMENDATIONS  Work with urban managers and landowners that perform weed and pest-control spraying to use more sustainable practices and promote public awareness about bats.  Partner with clean water initiatives to provide suitable water sources for bats.  Promote organic farming practices that reduce chemical use while reducing contamination issues of bats.

RESEARCH NEEDS

 Develop studies to evaluate the impacts to bat populations from urban and natural area pest spraying programs (e.g., mosquito spraying for West Nile virus control).  Perform studies to determine the concentrations of toxins being stored in bat tissues as a result of biomagnification through the food chain.  Determine how water pollution from wastewater treatment plants and agricultural effluvia affect insect and bat populations.

DISEASE RISK

Much of the negative stigma regarding bat colonies using anthropogenic structures relates to disease. Disease is addressed in its own section of the plan (see chapter VII. Bats and Disease), but it is worth questioning whether disease ecology is different in urban colonies, and what impact this may have on bat populations and human health. Diseases associated with bats, particularly rabies, often drive fears and perceptions of bats, and ultimately dictate whether people choose to exterminate or evict them from structures (O’Shea et al. 2011). Spread and susceptibility of rabies in a population of big brown bats using a highly urbanized setting along the northern Front Range of Colorado provided a number of insights into the relationship of this disease and the bat hosts (O’Shea et al 2014). Exposure to the disease, measured by prevalence of neutralizing antibodies, or seroprevalence, varied in bats by roost site, sex, and age. Histoplasmosis, a fungus associated with guano accumulations in anthropogenic structures, is not considered to be a human disease concern in Colorado based on the absence of known cases in the state and the dry climate which inhibits fungal growth (Baddley et al. 2011; Benedict and Mody 2016; see chapter VII. Bats and Disease).

GOAL DETERMINE IF A BETTER UNDERSTANDING OF DISEASE ECOLOGY OF BATS CAN POSITIVELY INFLUENCE PUBLIC PERCEPTION AND TOLERANCE OF BATS THAT ARE USING ANTHROPOGENIC STRUCTURES AS ROOSTS AND URBANIZED AREAS FOR HABITAT. Objective 1: Encourage safe watchable wildlife opportunities with bats through educational programs for both children and adults.

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Objective 2: Determine if urban bats are at a higher risk for disease, especially zoonotics, compared to bats living in natural areas.

Objective 3: Work with and educate public health officials, pest control companies, and the public about the risks of rabies and histoplasmosis in Colorado.

Objective 4: Educate the public, particularly those at high risk such as children, how to deal with sick bats when encountered.

MANAGEMENT RECOMMENDATIONS  Educate the public on safe interaction with bats, especially where roosts are present in occupied buildings.

RESEARCH NEEDS

 Determine whether roosting behavior and colony size are different in urban colonies.  Determine if colony size or parasite load can affect the transmission of other diseases besides rabies (Pearce et al. 2007).

LITERATURE CITED Allen, L. C., C. S. Richardson, G. F. McCracken, and T. H. Kunz. 2010. Birth size and postnatal growth in cave- and bridge-roosting Brazilian free-tailed bats. Journal of Zoology 280(1):8-16. Altringham, J. D. 2011. Bats: from evolution to conservation. Oxford, England: Oxford University Press. Ancilloto, L., M. T. Serangeli, and D. Russo. 2013. Curiosity killed the bat: domestic cats as bat predators. Mammalian Biology 78(5):369-373. Avila-Flores R., and B. M. Fenton. 2005. Use of spatial features by foraging insectivorous bats in a large urban landscape. Journal of Mammalogy 86(6):1193-1204. Baddley, J. W., K. L. Winthrop, N. M. Patkar, E. Delzell, T. Beukelman, F. Xie, L. Chen, and J. R. Curtis. 2011. Geographic distribution of endemic fungal infections among older persons, United States. Emerging Infectious Diseases 17:1664-1669. Benedict, K., and R. K. Mody. 2016. Epidemiology of histoplasmosis outbreaks, United States, 1938-2013. Emerging Infectious Diseases 22:370-378. Bennett, V. J., and A. A. Zurcher. 2012. When corridors collide: road-related disturbance in commuting bats. The Journal of Wildlife Management 77(1):93-101. Berthinussen, A., and J. Altringham. 2012. The effect of a major road on bat activity and diversity. Journal of Applied Ecology 49:82-89. Colorado State Demography Office. 2016. Colorado’s 2016 population and economic overview. Available: https://demography.dola.colorado.gov/crosstabs/2016-overview/.

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Duchamp, J. E., and R. K. Swihart. 2008. Shifts in bat community structure related to evolved traits and features of human-altered landscapes. Landscape Ecology 23:849-860. Everette, A. L., T. J. O’Shea, L. E. Ellison, L. A. Stone, and J. L. McCance. 2001. Bat use of a high-plains urban wildlife refuge. Wildlife Society Bulletin 29(3):967-974. Fagan, K. E., E. V. Willcox, L. T. Tran, R. F. Bernard, and W. H. Stiver. 2017. Roost selection by bats in buildings, Great Smoky Mountains National Park. The Journal of Wildlife Management: 82:424-434. Garner, E. 2016. Colorado’s 2016 population and economic overview. State Demography Office, Denver, Colorado. Kalcounis-Rueppell, M. C., V. H. Payne, S. R. Huff, and A. L. Boyko. 2007. Effects of wastewater treatment plant effluent on bat foraging ecology in an urban stream system. Biological Conservation 138:120- 130. Keeley, B. W., and M. D. Tuttle. 1999. Bats in American bridges. Bat Conservation International. Kurta, A., and J. A. Teramino. 1992. Bat community structure in an urban park. Ecography 15:257-261. Lausen, C. L., and R. M. R. Barclay. 2006. Benefits of living in a building: big brown bats (Eptesicus fuscus) in rocks versus buildings. Journal of Mammalogy 87(2):362-370. Lewanzik, D. and C. C. Voigt. 2014. Artificial light puts ecosystem services of frugivorous bats at risk. Journal of Applied Ecology 51(2):388-394. Luck, G. W., L. Smallbone, C. Threlfall, and B. Law. 2013. Patterns in bat functional guilds across multiple urban centres in South-eastern Australia. Landscape Ecology 28:455-469. Mering, E. D., and C. L. Chambers. 2014. Thinking outside the box: a review of artificial roosts for bats. Wildlife Society Bulletin 38:741-751. Miner, K. L., and D. C. Stokes. 2005. Bats in the South coast ecoregion: status, conservation Issues, and research needs. USDA Forest Service Gen. Tech. Rep. PSW-GTR-195:211-227. Neubaum, D. J. 2005. Noteworthy records of the Eastern red bat on the northern Front Range of Colorado. Prairie Naturalist 37:41-42. Neubaum, D. J. 2018. Unsuspected retreats: autumn roosts and presumed hibernacula used by little brown myotis in Colorado. Manuscript submitted for publication. Journal of Mammalogy. Neubaum, D. J., K. R. Wilson, and T. J. O'Shea. 2007. Urban maternity-roost selection by big brown bats in Colorado. Journal of Wildlife Management 71:728-736. O'Shea, T. J., and J. J. Johnston. 2009. Environmental contaminants and bats; investigating exposure and effects. Pp. 500-528 in Ecological and behavioral methods for the study of bats (T. H. Kunz and S. Parsons, eds). John Hopkins University Press, Baltimore, MY. O'Shea, T. J., A. L. Everette, and L. E. Ellison. 2001. Cyclodiene insecticide, DDE, DDT, arsenic, and mercury contamination of big brown bats (Eptesicus fuscus) foraging at a Colorado superfund Site. Archives of Environmental Contamination & Toxicology 40:112-120.

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O'Shea, T. J., R. A. Bowen, T. R. Stanley, V. Shankar, and C. E. Rupprecht. 2014. Variability in seroprevalence of rabies virus neutralizing antibodies and associated factors in a Colorado population of big brown bats (Eptesicus fuscus). PLoS ONE 9:e86261. O’Shea, T. J., L. E. Ellison, D. J. Neubaum, M. A. Neubaum, C. A. Reynolds, and R. A. Bowen. 2010. Recruitment in a Colorado population of big brown bats: breeding probabilities, litter size, and first- year survival. Journal of Mammalogy 91(2):418-428. O’Shea, T. J., D. J. Neubaum, M. A. Neubaum, P. M. Cryan, L. E. Ellison, T. R. Stanley, C. E. Rupprecht, W. J. Pape, and R. A. Bowen. 2011. Bat ecology and public health surveillance for rabies in an urbanizing region of Colorado. Urban Ecosystems 14:665-697. Pearce, H. and C. L. Walters. 2011. Do green roofs provide habitat for bats in urban areas? PLoS ONE 6(5): e20483. doi:10.1371/journal.pone.0020483. Pearce, R. D., T. J. O'Shea, V. Shankar, and C. E. Rupprecht. 2007. Lack of association between ectoparasite intensities and rabies virus neutralizing antibody seroprevalence in wild big brown bats (Eptesicus fuscus), Fort Collins, Colorado. Vector-Borne and Zoonotic Diseases 7:489. Pilosof, S., C. Korine, M. S. Moore, and B. R. Krasnov. 2013. Effects of sewage-water contamination on the immune response of a desert bat. Mammalian Biology 183. Racey, P. A. and S. M. Swift. 1981. Variations in gestation length in a colony of pipstrelle bats (Pipistrellus pipistrellus) from year to year. Journal of Reproduction and Fertility 61(1):123-129. Van Horne, B. 1983. Density as a misleading indicator of habitat quality. Journal of Wildlife Management 47:893-901. Vaughan, N., G. Jones, and S. Harris. 1996. Effects of sewage effluent on the activity of bats (Chiroptera: Vespertilionidae) foraging along rivers. Biological Conservation 78:337-343. Warner, K. A. 2016. Investigating the effects of noise pollution from energy development on the bat community in the Piceance Basin. Colorado State University, Fort Collins, Colorado. White, E. P. 2004. Factors affecting bat house occupancy in Colorado. The Southwestern Naturalist 49:344-349. Wickramasinghe, L. P., S. Harris, G. Jones, and N. Vaughn. 2004. Abundance and species richness of nocturnal insects on organic and conventional farms: effects of agricultural intensification on bat foraging. Conservation Biology 18(5):1283-1292. Williams, K. 2012. Bat foraging activity and insect abundance in relation to light intensity on Baylor University Campus. Thesis. Baylor University, Waco TX. Williams, L. M., and M. C. Brittingham. 1997. Selection of maternity roosts by big brown bats. Journal of Wildlife Management 61:359-368.

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VII. BATS AND DISEASE

By Mark A. Hayes, Michael D. Dixon, Kirk W. Navo, and Daniel J. Neubaum

This section gives a brief introduction to diseases related to bats in Colorado. We present this information in two parts. The first part addresses bat-related diseases of public health importance, focusing on rabies. The second part addresses diseases that can or do affect bat populations, and may be of concern to biologists and managers with interests in bat populations. The discussion of bats and disease in Colorado presented here is not intended to be a comprehensive treatment of the subject, but rather strives to provide enough information so that interested readers will have a sense for where to look for more information. Information about diseases of bats that affect humans can be found at the Centers for Disease Control and Prevention (CDC) website (www.cdc.gov/rabies/index.html). A review of the ecology of infectious diseases of bats can be found in Hayman et al. (2013), and a review of bats as important reservoirs of viruses can be found in Calisher et al. (2006) and Moratelli and Calisher (2015).

BAT RELATED DISEASES OF PUBLIC HEALTH IMPORTANCE

There are two main categories of bat-related diseases relevant to public health: diseases carried by bats; and diseases that may be of concern to researchers and residents who work in or near bat roosts, or have bats roosting in buildings, but which are not primarily transmitted by bats. Worldwide, bats are known or suspected to be associated with a variety of human diseases. Noteworthy among these diseases are Marburg hemorrhagic fevers, Hendra virus disease, and Nipah virus encephalitis (Calisher et al. 2006), none of which are endemic to the United States. Bats in Colorado have been documented with coronaviruses (Dominguez et al. 2007). A general overview of public health concerns and bat researchers is provided in Kunz and Parsons (2009).

In Colorado, rabies is considered to be the key bat-related disease with a risk of direct bat-human transmission (O’Shea et al. 2011), with bats and skunks as the main sources in the state (see Colorado Department of Public Health & Environment (CDPHE) for information; www.colorado.gov/pacific/cdphe/rabies). Rabies is a viral disease that infects the central nervous system of mammals and is almost always fatal to humans once symptoms occur. Rabies virus can be transmitted via saliva from the bites of infected animals, and when infected saliva contacts blood via wounds or mucous membranes. Bats with rabies may appear normal or they may behave abnormally. For example, they may be observed roosting in unusual places, such as on the outsides of buildings during daytime; they may be seen Swabbing a bat for detection of rabies flying in daylight, they may not appear to have a fear of virus. Photo by D. Neubaum. people or predators; and they may behave very aggressively or appear very lethargic. Human exposure

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to rabies can be reduced by minimizing contact with bats, particularly those that appear sick or that are behaving abnormally (Kunz and Parsons 2009). Information on annual testing for rabies in Colorado is available at the CDPHE website.

PROPHYLAXIS AND PREVENTATIVE MEASURES Bat researchers and wildlife professionals have an increased risk of exposure to rabies, but this risk can be reduced by taking precautions such as wearing leather gloves while handling bats, undergoing pre- exposure vaccination, and regularly having antibody titer checks. Prior to working with bats, wildlife professionals and students should consult their doctor about pre-exposure rabies vaccination. Basic information on the rabies vaccine is available through the CDC (https://www.cdc.gov/rabies/resources/acip_recommendations.html). It is generally recommended that anyone who will have direct contact with bats complete the full pre-exposure vaccination series. Following vaccination, titer checks (via serology testing) are recommended annually for those in frequent contact with bats, or at least every other year to ensure that antibody levels remain high enough to protect from infection. The CDC recommends the use of an end-point titer, rather than a coarser “greater than or less than” titer, as the former allows tracking of titer levels over time. Such information will provide guidance on the need for annual titer testing. One recommended test is the Rapid Fluorescent Focus Inhibition Test, available through the College of Veterinary Medicine at Kansas State University. We strongly recommend wearing leather gloves on both hands covered by nitrile gloves when capturing and handling bats. Consideration of nitrile gloves for other assistants handling field equipment during capture surveys is encouraged. Information on the types of gloves to consider can be found in Freeman and Lemen (2009). When potentially exposed to the saliva of a rabid bat, the CDC recommends irrigating the wound as soon as possible with soap and water followed with a providine-iodine solution, and seeking medical advice immediately. If this is unavailable in the field, an antiseptic concentration of ethanol may be used until further treatment is available. Following exposure, the bat should be retained and submitted for testing to determine if vaccinated individuals will require post-exposure prophylaxis. Unvaccinated individuals require post-exposure vaccination and immunoglobulin. For updated post-exposure treatment recommendations, visit the CDC’s rabies page: www.cdc.gov/rabies/medical_care/. Such rigorous response measures emphasize the need for personnel to wear appropriate protection (leather gloves) at all times when handling bats, as the ramifications to the person and bat can be severe. See additional information and recommendations on this matter at Colorado Parks and Wildlife’s (CPW) website, including information for obtaining a Scientific Collection Permit, which is required for anyone who will be handling wildlife, including bats (http://cpw.state.co.us/learn/Pages/WildlifeHealthWNS.aspx).

DISEASE RISKS OF RESEARCH AT BAT COLONIES Bat roosts can also present additional risks for wildlife professionals. While bats do not carry Hantavirus, it is sometimes associated with rodent urine and feces, which may occur in buildings, caves, and mines, and can cause the acute and often fatal Hantavirus Pulmonary Syndrome. A fungus sometimes present in cave soils, and other areas with significant bird and bat guano, can cause histoplasmosis, which is a

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lung infection that may be life threatening to immunocompromised individuals. Typical disinfection practices and the use of gloves can reduce the risk of exposure to these diseases, as can the use of respiratory protection. The CDC has published guidelines on prevention of histoplasmosis in at-risk workers, which includes bat researchers (Lenhart et al. 2004). Because Colorado’s climate is generally dry enough to inhibit growth of this fungus, histoplasmosis is not a reportable event in Colorado (Baddley et al. 2011). Only outbreaks are considered reportable, and to date, no outbreaks of this fungus have been reported in Colorado (Benedict and Mody 2016). However, caution should be taken when working in humid or moist areas, and large concentrations of bat guano are present.

DISEASES THAT AFFECT BATS AND THEIR POPULATIONS

Based on currently available information the only disease known to have large impacts on bat populations in North America, and which is likely to impact future bat populations in Colorado, is white- nose syndrome (WNS). Currently WNS is restricted to eastern North America and the eastern edge of some central plains states, the Texas panhandle, and Washington state, but has not been detected in Colorado (https://www.whitenosesyndrome.org/about/where-is-it-now). Although other diseases, such as rabies, West Nile Virus, and coronaviruses, affect bats in the western United States, none of these diseases are known to result in large die-offs of bat colonies or populations in Colorado.

WNS is a disease that affects hibernating bats that was first documented in February 2006 in eastern North America. Castle and Cryan (2010) provide an overview of this disease designed for natural resource managers. During the initial 2-year period after the disease emerged, some bat populations in eastern North America may have experienced more than a 75% decline, and over 5.5 million bats of several species are estimated to have died in the period from 2006–2011, leading to a regional population collapse and may result in the extinction of some of these species Bat with White-Nose Syndrome. Photo by S. Taylor. (USFWS 2012). WNS has had a particularly destructive impact on species that hibernate in large aggregations in the eastern United States and Canada (Castle and Cryan 2010).

The fungal spcecies Pseudogymnoascus destructans (Pd; formerly Geomyces) is now considered to be the causal agent of WNS (Minnis and Lindner 2013), and is transmitted by bat-to-bat and human (recreational/caving, research) modes of transmission. This fungus may be an invasive species recently introduced into bat hibernation habitats in North America, or it may be a virulent strain of a fungus with global distribution. At the time of this writing, WNS has not been documented in Colorado (www.whitenosesyndrome.org), however it was confirmed in the panhandle of Texas in 2017. There exists an almost continuous distribution of cave/karst habitat from areas with confirmed WNS, the

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southwestern tablelands in the southern section of the Great Plains, and southeastern Colorado (Culver et al. 1999; Veni 2002). It is possible that the southwestern tablelands could provide a bridge for this disease to spread into western North America, including Colorado, and it is yet to be determined how the WNS presence further west in Washington arrived.

The Pd fungi are common in cold environments, capable of thriving in low nutrient conditions, and are commonly dispersed by animals, humans, air currents, and water (Hayes 2012; Furbino et al. 2014). These qualities will continue to present substantial challenges to those charged with controlling the spread of WNS and its causative agent in western North America. However, the ecology of western bat species may be different than that of eastern bats which could influence how WNS spreads. Relative to population estimates, the number of bats using caves and mines tends to be lower in the West, and concentrations of bats using these features is often less than found in eastern situations. Bats in the West are known to hibernate in other features such as rock crevices. Use of these roost structures by bats, if in small aggregations, may inhibit the spread of WNS, but more research on the winter roosting ecology of most species in Colorado is still needed. Because we know so little and this disease could devastate our bat populations we strongly recommend implementing and following decontamination guidelines (see links below) and carefully considering the need to visit bat roosts or capture and handling of bats as humans can transfer the fungal spores. Current information on WNS can be found at www.whitenosesyndrome.org. This website provides access to key documents and resources, including decontamination protocols, maps of disease spread, the national response plan, information on research, and educational resources.

It is critical that all researchers and agency personnel follow the guidelines for decontamination of all Researchers swabbing a bat for detection of equipment and gear to help prevent the spread of White-Nose Syndrome. Photo by S. Taylor. WNS. Information on decontamination protocols can be found at federal (https://www.whitenosesyndrome.org) and state (http://cpw.state.co.us/learn /Pages/WildlifeHealthWNS.aspx) websites.

We address two categories of issues relating to bats and disease in Colorado: Monitoring of WNS, and inadequate knowledge of bat diseases in Colorado.

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MONITORING OF WNS IN COLORADO

GOAL ENCOURAGE PROACTIVE MEASURES OF MONITORING THAT WILL ASSIST WITH MANAGEMENT OF BAT SPECIES IN COLORADO IF WNS REACHES THE STATE. Objective 1: Reduce gaps in natural history of bats in Colorado, such as roosting ecology, and attain a better understanding of winter roost selection by bats in Colorado.

MANAGEMENT RECOMMENDATIONS  Measure and describe microclimate conditions (e.g., temperature and relative humidity) inside known and potential hibernacula in Colorado.  Determine what conditions facilitate the growth of the causal fungi and development of WNS, and identify hibernacula in Colorado that meet these conditions.  Continue surveillance for the causal fungus and WNS in Colorado.  Improve understanding of the roosting needs of bats that hibernate in Colorado.  Improve understanding of how bats disperse among hibernacula and maternity sites in Colorado.  Examine seasonal, regional and species-related differences in fungal diversity among bats in Colorado.

INADEQUATE KNOWLEDGE OF BATS AND DISEASE IN COLORADO

GOAL IMPROVE THE UNDERSTANDING OF DISEASES THAT INFECT AND FUNCTION IN BAT SPECIES OF COLORADO AND THE POTENTIAL IMPACTS THEY CARRY TO LOCAL AND REGIONAL POPULATIONS. Objective 1: Promote research to attain a better understanding of the prevalence of diseases in Colorado bat populations.

Objective 2: Investigate prevalence of coronavirus and fungal communities in wild bats across Colorado.

MANAGEMENT RECOMMENDATIONS  Secure funding sources that support proactive inventory and monitoring efforts related to bat species and roosting requirements.  Initiate policy decisions that facilitate disease monitoring on public and private lands.

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 Identify important winter roosts used by bats in Colorado and protect these sites with seasonal closures if necessary. These sites may provide future treatment locations if proactive methods, such as exposure to ultraviolet light, are successfully developed (Palmer et al. 2018).  Establish long-term and strategic monitoring sites in Colorado that are critical to early detection of WNS. Consider the implications of winter roost disturbance in WNS related activities, and minimize the risk of impacts to bat populations. Conduct such activities, when possible, during non-winter seasons, and/or limit the frequency of visits to hibernacula.

LITERATURE CITED Baddley, J. W., K. L. Winthrop, N. M. Patkar, E. Delzell, T. Beukelman, F. Xie, L. Chen, and J. R. Curtis. 2011. Geographic distribution of endemic fungal infections among older persons, United States. Emerging Infectious Diseases 17:1664-1669. Benedict, K., and R. K. Mody. 2016. Epidemiology of histoplasmosis outbreaks, United States, 1938-2013. Emerging Infectious Diseases 22:370-378. Calisher, C. H., J. E. Childs, H. E. Field, K. V. Holmes, and T. Schountz. 2006. Bats: important reservoir hosts of emerging viruses. Clinical microbiology reviews 19: 531–545. Castle, K. T., and P. M. Cryan. 2010. White-nose syndrome in bats: A primer for resource managers. Park Science 27: 20–25. Culver, D. C., H. H. Hobbs III, M. C. Christman, and L. L. Master. 1999. Distribution map of caves and cave animals in the United States. Journal of Cave and Karst Studies 61: 139–140. Dominguez, S. R., T. J. O'Shea, L. M. Oko, and K. V. Holmes. 2007. Detection of Group 1 Coronaviruses in Bats in North America. Emerging Infectious Diseases 13: 1295–1300. Freeman, P. W., and C. A. Lemen. 2009. Puncture-Resistance of Gloves for Handling Bats. Mammalogy Papers: University of Nebraska State Museum. Paper 118. http://digitalcommons.unl.edu/museummammalogy/118 Furbino, L. E., V. M. Godinho, I. F. Santiago, F. M. Pellizari, T. M. Alves, C. L. Zani, P. A. Junior, A. J. Romanha, A. G. Carvalho, L. H. Gil, and C. A. Rosa. 2014. Diversity patterns, ecology and biological activities of fungal communities associated with the endemic macroalgae across the Antarctic Peninsula. Microbial Ecology 67: 775–787. Hayes, M. A. 2012. The Geomyces fungi: ecology and distribution. Bioscience 62: 819–823. Hayman, D. T. S., R. A. Bowen, P. M. Cryan, G. F. McCracken, T. J. O’Shea, A. J. Peel, A. Gilbert, C. T. Webb, and J. L. N. Wood. 2013. Ecology of zoonotic infectious diseases in bats: current knowledge and future directions. Zoonoses and Public Health 60: 2–21. Kunz, T. H. and S. Parsons, editors. 2009. Ecological and Behavioral Methods for the Study of Bats. The John Hopkins University Press, Baltimore, Maryland. Lenhart, S. W., C. M. P. Schafer, M. Singal and R. A. Hajjeh. 2004. NIOSH: Histoplasmosis: Protecting Workers at Risk-Revised Edition. National Institute for Occupational Safety and Health. Cincinnati, Ohio.

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Minnis, A. M., and D. L. Lindner. 2013. Phylogenetic evaluation of Geomyces and allies reveals no close relatives of Pseudogymnoascus destrcutans, comb. Nov., in bat hibernacula of eastern North America. Fungal Biology 117: 638–649. Moratelli, R., and C. H. Calisher. 2015. Bats and zoonotic viruses: can we confidently link bats with emerging deadly viruses? Memórias do Instituto Oswaldo Cruz 110: 1–22. O'Shea, T.J., D. J. Neubaum, M. A. Neubaum, P. M. Cryan, L. E. Ellison, T. R. Stanley, C. E. Rupprecht, W. J. Pape, and R. A. Bowen. 2011. Bat ecology and public health surveillance for rabies in an urbanizing region of Colorado. Urban Ecosystems 14: 665–697. Palmer, J. M., K. P. Drees, J. T. Foster, and D. L. Lindner. 2018. Extreme sensitivity to ultraviolet light in the fungal pathogen causing white-nose syndrome of bats. Nature Communications 9:35. USFWS (US Fish and Wildlife Service). 2012. North American bat death toll exceeds 5.5 million from white-nose syndrome. USFWS. (26 April 2012; https://www.fws.gov/northeast/feature_archive/Feature.cfm?id=794592078 ). Veni, G. 2002. Revising the karst map of the United States. Journal of Cave and Karst Studies 64: 45–50.

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VIII. ENERGY DEVELOPMENT

By Rogelio M. Rodriguez, Michael Schirmacher, Kirk W. Navo, and Daniel J. Neubaum

This chapter discusses current energy development (i.e., wind, oil and gas, and solar), and the potential impact to bats and their habitats. The development and technology of each energy sector is introduced, followed by a section that describes possible direct (e.g., collision) and indirect (e.g., habitat degradation) impacts to bats. It is important to understand that within each energy sector the technology being utilized may vary and thus the associated impacts, both actual and potential, may differ as well. For example, solar energy can be produced using photovoltaic (panel) arrays, or heat generation with lenses or mirrors at concentrated solar power systems. Due to size requirements needed to capture the same amount of energy as mirror arrays, photovoltaic arrays may disturb more habitats, an indirect effect on bats. However, mirror arrays have the potential to directly incinerate bats due to the high levels of heat associated with energy transfer. In addition, it should also be considered that mirror arrays have risks associated with high saline water in evaporation ponds and chemical exposure for plants with steam generator designs. We provide some examples of technology types for each energy sector. However, it should be noted that energy development technologies can arise and change rapidly. Therefore, the need for stakeholders to work together to investigate the potential impacts to bats and their habitats from current and future energy development technology will be important.

We address direct impacts, degradation/loss of habitat, combined impacts, and other impacts to bats for three types of energy development in Colorado: wind energy potential and technology, oil and gas potential and technology, and solar potential and technology.

WIND ENERGY POTENTIAL AND TECHNOLOGY

Wind Energy development in U.S. ranks 2nd in the world, with 89,077 MW installed as of 2017 (AWEA 2017a). Through 2016, Colorado was ranked 9th in the U.S. for installed wind energy and 13th in the US for potential wind energy development (AWEA 2017b). Most wind energy potential in Colorado occurs in the eastern plains and foothills of the Rocky Mountains (Fig 8.1). The Colorado Renewable Portfolio Standard (RPS), as modified in 2010, requires investor-owned utilities and cooperatives to provide 30% and 20% of their electricity, respectively, through renewable and/or recycled energy by 2020. As of 2017, Colorado Wind farm in northeast Colorado. Photo by P. Cryan. has 26 active wind farms with 3,026 MW of wind

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capacity, all of which are situated on the Front Range and eastern plains (Fig. 8.2).

Wind energy technologies use the force of the wind to generate electricity, charge batteries, pump water, and/or grind grain (EERE 2014a). The most commonly used wind energy technology is the horizontal axis turbine which is a rotor with 2–3 blades set on a tall tower, typically 80–100 m above ground (Fig. 8.3; EERE 2014b). Other designs are being considered but most are still in the testing phase. An example of a design in the testing stage is a tethered kite that rotates in the wind at approximately 140–310 m above ground, which is being developed by Makani in partnership with Google (Makani 2014).

Figure 8.1. Colorado annual average wind speed (80m agl) suggests that the majority of wind development will occur on the Front Range and eastern plains (National Renewable Energy Laboratory, https://windexchange.energy.gov/maps-data/15, Accessed December 2017).

Bat fatalities resulting from strikes with wind turbine blades are well documented and have the potential to impact local and regional bat populations (O’Shea et al. 2016; Hammerson et al. 2017). Unlike other energy sectors, wind development causes consistent, high levels of direct bat mortality, with an estimated 840,486–1,690,696 bats killed between 2000–2011 in the United States and Canada

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(Arnett and Baerwald 2013). Migratory bats are heavily impacted as they are likely to be utilizing the same wind paths as those targeted for wind energy development. A number of reasons for bat’s approaching turbines have been suggested, including aspects tied to the tallest objects on the landscape, such as mating behavior (Cryan 2008) and roost structures (Cryan et al. 2014). The fatalities themselves may be the result of barotraumas (decompression sickness) from flying too close to the blades (Baerwald et al. 2008), but more often are probably associated with traumatic injuries from the impact of collisions (Rollins et al. 2012). A number of measures to reduce bat fatalities at wind facilities have been studied (Arnett and May 2016), including adjusting turbine operations (e.g., wind speed triggers and blade angle; Baerwald et al. 2009), and placing texture on monopoles to help bats distinguish them from naturally used features (Conley 2017). Using deterrents such as broadband ultrasound broadcasts (Arnett et al. 2013; Lindsey 2017) and ultraviolet illumination (Gorresen et al. 2015; Cryan et al. 2017) may also prove effective in mitigating bat fatalities.

Figure 8.2. Wind farms in Colorado producing energy as of 2017 (AWEA US Wind Industry Map, http://gis.awea.org/arcgisportal/apps/webappviewer/index.html, Accessed October, 2017). Inset photo by P. Cryan.

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GOAL REDUCE THE POTENTIAL FOR BAT FATALITIES ASSOCIATED WITH WIND ENERGY DEVELOPMENT. Objective 1: Collect data of bat activity prior to construction of wind farms to determine species affected and the level of potential impact to those bat populations.

Objective 2: Consider locating wind farms in areas of low bat activity.

Objective 3: Encourage wind facilities to implement proactive measures that are found to reduce bat fatalities such as turbine adjustments or deterrents.

Objective 4: Conduct post construction surveys for bat fatalities to collect data on species occurrence and to improve species specific mitigation.

RESEARCH NEEDS  Fund research to develop effective bat deterrents at wind turbines.

Figure 8.3. Horizontal axis wind turbines used to generate electricity in eastern Colorado. Photos by J. Reitz

OIL AND GAS POTENTIAL AND TECHNOLOGY

Nationally, Colorado accounts for 10% of the natural gas reserves and almost 2% of the crude oil reserves. Advancements in horizontal drilling and hydraulic fracturing have allowed access to unconventional reservoirs, such as tight sands, coal bed methane, and shale rock (COGA 2014). Hydraulic fracturing is used in 9 out of 10 natural gas wells in the U.S. Shale gas reservoirs, or plays, are

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distributed across the U.S. (Fig. 8.4) and generally are found at depths ranging from 152–4,115 m. Growth in shale gas production is expected to increase from 5.0 trillion cubic feet (Tcf) in 2010 to 13.6 Tcf by 2035 (USEIA 2012). Technology used to extract oil and gas varies but the overall concept is to use pressure, either natural pressure or created pressure from pumps, gas, and/or liquid. Extracting natural gas and oil from previously unobtainable plays requires fracturing the rock formation. In hydraulic fracturing operations, water and various chemicals are used to create fractures. Suspended in the fluid is a propping agent, typically sand, which maintains openings and allows gas to flow to the well (Carter et al. 1996; Entrekin et al. 2011). The hydraulic fracturing process requires large amounts of water per well to fracture the shale formation. On average, 2–4 million gallons (can exceed 9 million gallons) are used per operation (Satterfield et al. 2008; GWPC and ALL Consulting 2009; API 2010). Water can be withdrawn from a nearby source or transported by truck or pipeline, and stored on-site in impoundments (GWPC and ALL Consulting 2009). Because ground and surface water are hydraulically connected, these operations could change the quantity and quality of both (Winter et al. 1998).

Figure 8.4. Location and size of natural gas reservoirs, or plays, in the United States as of 2015 (US Energy Information Administration, 2015).

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DIRECT IMPACTS A potential source for impacts to bats at oil and gas developments are the pits created to further separate oil from produced water (production skim pits), to store drilling fluids (reserve pits), to vent hydrogen sulfide gas from production wells (flare pits), or to store oil field waste (centralized oilfield wastewater disposal facilities). Pits containing oil or other oil-based drilling fluids can trap bats attempting to drink or pursuing prey (i.e., insects) on the surface (Ramirez 1999). Finley et al. (1983) retrieved 27 dead bats of 6 species from an oil and gas pit near Rifle, Colorado over a 16 month period. Large numbers of insects have been entrapped in oil production pits (Horvath and Zeil 1996; Bernáth et al. 2001), thus leading to a higher possibility of entrapment by bats due to attraction to insect prey. Esmoil and Anderson (1995) documented bats among the wildlife mortalities observed at oil pits in Wyoming. Another impact of these pits is the composition of oil and other toxic compounds that could be ingested by bats (Ramirez 2000). As has been determined for birds (USFWS 2009), bats could ingest toxic amounts of oil, salt, or other chemicals when preening their bodies after contact with the surface or attempting to drink from the pit. Bats may also die from hypothermia if the oil damages the insulation properties of their fur (Ramirez 1999, 2000). Although the annual estimate of migratory bird deaths from oil reserve pits vary from 0.5–2 million (Ramirez 1999; Trail 2006), it is unknown what the cumulative impact is to bats, as monitoring is not occurring and bats may be hard to recover (Ramirez 1999, 2000). In 2008, the Colorado Oil and Gas Conservation Commission (COGCC) adopted rules on pits to mitigate impacts to wildlife. Rule 902 calls for cleaning of pits and removal of oil or condensate in a pit within 24 hours of discovery and that netting or fencing should occur. Because fencing is not considered to deter bats and birds, many land managers on public lands are requiring closed-loop systems that eliminate pits (V. Koehler, pers. comm., 2014; COGCC 2015). These measures may help reduce impacts to wildlife, including bats. It is not known if netting causes bats to become entangled. In addition, the rule does not apply to all pits.

Another potential source of direct mortality at oil and gas developments is open exhaust stacks where bats may roost and be incinerated when the unit is fired up (BLM 1994, 1996). Data gathered by the Bureau of Land Management (BLM) in an assessment of 2,500 wells in the San Juan Basin of New Mexico and Colorado resulted in 252 dead birds and bats (the report did not state the proportion of either; BLM 1995). Dead bats have been observed around exhaust stacks in Wyoming as well (Schwab and DuBois 2006). The cumulative impact to bats is not known because of site variability, the lack of monitoring and/or success in recovering carcasses. The COGGC Rule 604b requires all stacks, vents, or other appropriate equipment to prevent entry by wildlife, including migratory birds (COGCC 2015). This regulation may help mitigate impacts, such as entrapment, to bats as well.

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GOAL REDUCE THE POTENTIAL FOR BAT MORTALITIES ASSOCIATED WITH OIL AND GAS PITS AND EXHAUST STACKS. Objective 1: Refer developers and operators to existing policies and rules by the COGCC regulating oil and gas development in the state including conserving wildlife and wildlife habitat, and to the BLM and US Forest Service (USFS) for projects being developed on federal lands.

Objective 2: Consult with the Colorado Parks and Wildlife (CPW) per the COGCC’s rules or to the BLM and USFS regarding threats to bats when establishing new drill sites.

Objective 3: Provide information and technical support to oil and gas developers and regulatory personnel about sensitive bat species, bat conservation practices, and measures to reduce mortalities, such as locating pits away from known or potential roost sites.

Objective 4: Provide information and technical support to oil and gas developers and regulatory personnel to monitor the success of bat conservation measures.

MANAGEMENT RECOMMENDATIONS  Refer developers to existing policies for oil and gas development, such as the COGCC’s “Migratory Bird Policy,” that states screening shall be installed on exhaust stacks and accumulations of oil should be removed from pits as well as netting installed over pits to avoid use by migratory birds. Such policies would also be beneficial to bats by minimizing their use of these facilities and the associated impacts.  Continue to recommend use of closed-looped systems to reduce likelihood of bats drinking from contaminated water.  Monitor pits for bat mortalities and develop a plan for reporting and mitigation measures.  Construct alternative freshwater sources adjacent to permanent pits to provide wildlife with an alternative safe water source and contribute to dietary dilution of toxic compounds.  Operators should report all dead or tangled bats to CPW and COGCC staff.

RESEARCH NEEDS

 Do bats drink from contaminated waste water sites associated with oil and gas extraction?  Do the current flagging and net designs required by COGCC keep bats out of contaminated water sources?  Are the nets themselves, rather than the water source, a cause of bat mortality?  Are bat mortalities resulting from exhaust stacks associated with oil and gas activities?

LOSS/DEGRADATION OF HABITAT Habitat loss, degradation, and fragmentation from oil and gas development have been known to affect wildlife populations in a number of ways (Riley et al. 2012; Ramirez and Mosley 2015). Specifically for

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bats, oil and gas developments have the potential to directly impact bat populations by limiting roosting and foraging habitats (Hein 2012). Fragmentation from oil and gas development could reduce connectivity of habitats used by bats. In addition to physical disturbances, sensory disturbances such as noise and light may also lead to lower activity and habitat use by bats. Due to noise pollution created by drilling activities, areas of oil and gas development on the Piceance Basin of northwestern Colorado were used less by bats than control sites (Warner 2016). Development methods that use large amounts of water could impact bats in already arid environments, particularly lactating females with higher water requirements (Hein 2012; Riley et al. 2012; Ramirez and Mosley 2015). Bats utilizing waste water pits associated with drill sites may accumulate heavy metals in their systems, as noted from other sites with water contamination (O’Shea et al. 2001).

GOAL PREVENT THE LOSS/DEGRADATION OF HABITAT FROM OIL AND GAS DEVELOPMENTS IN COLORADO. Objective 1: Refer developers to existing policies and rules by the COGCC regulating oil and gas development in the state including conserving wildlife and wildlife habitat. Consult with CPW per COGCC rules on state lands and to the BLM and USFS for projects being developed on federal lands. Also, reference other supportive guidelines, such as those by the Colorado Mule Deer Association and Colorado Wildlife Federation (2006).

Objective 2: Preserve and improve bat habitat through land use planning. Provide information to land managers and county planners about the importance of these habitats to bats and other wildlife, and conservation strategies to minimize potential impacts to their habitats.

Objective 3: Encourage collection of acoustic bat activity data for development areas prior to drilling.

Objective 4: Based on pre-development data, reduce drilling activity during peak hours of activity for bats in areas where surveys found high bat use.

MANAGEMENT RECOMMENDATIONS  Consider avoidance of important bat habitat, and mitigate for unavoidable habitat impact.  Use sound walls at drill pads to dampen noise in areas shown to be important bat habitat by pre-development survey data.  Consolidate drilling operations in an area, both spatially and temporally, so impacts occur at the same time, leaving other areas undisturbed.  Consider cumulative habitat loss/degradation (e.g., urbanization, energy development, and agriculture) and mitigate at a landscape scale.

RESEARCH NEEDS

 How do bats move across the landscape in areas where oil and gas development occurs?

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 Develop efficient methods of monitoring and reporting sound levels at drill pads.  Are their important migratory routes for bats in areas of oil and gas development?  How do multiple oil and gas facilities across the landscape affect bat populations?  Test a wide range of relevant noise levels to better understand the spatial extent of noise disturbance for bats at drill sites (Warner 2016).  Investigate technologies to reduce noise generated from the drilling process, such as sound walls, as it relates to bats.  Test the impacts of light pollution generated at drilling sites (Warner 2016). Do bats avoid lighted drill rigs in areas that would otherwise be dark?  Do bats forage on insect aggregations around drill pad lights and does this offset potential lowered activity surrounding the site?

GOAL PRESERVE AND IMPROVE WETLAND/RIPARIAN HABITAT THROUGH LAND USE PLANNING. Objective 1: Refer oil and gas developers to existing policies and rules by the COGCC regulating oil and gas development in the state, including conserving wildlife and their habitat. Consult with CPW for COGCC rules on state lands, and to the BLM and USFS for projects being developed on federal lands. Reference other supportive guidelines, such as those by the Colorado Mule Deer Association and Colorado Wildlife Federation (2006).

Objective 2: Provide information to land managers and county planners about the importance of these habitats to bats and other wildlife, and promote the conservation of wetlands.

MANAGEMENT RECOMMENDATIONS  Contact the Army Corps of Engineers for permitting and consult with CPW, Ducks Unlimited, US Fish and Wildlife Service, or other experts for advice regarding wetland management.  Mitigate for water taken from natural and agricultural sources as required by the state.  Consider connectivity of roosting, foraging and commuting habitat in relation to water sources.  Consider climate change impacts on water loss in relation to developmental loss of water.  Promote construction of alternative freshwater sources for bat use.

RESEARCH NEEDS

 Expand current knowledge of how bats use wetlands/riparian habitat. How do bats find new sources of water? Where and when is water needed most for bats?  If new water sources are constructed, how successful are they in mitigating the loss of historic water sources or preventing bats from using contaminated sources?

COMBINATION OF MULTIPLE IMPACTS Fragmentation and water loss could lead to underestimated impacts to bats.

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GOAL PRESERVE/CONSERVE AND IMPROVE BAT HABITAT THROUGH LAND USE PLANNING. Objective 1: Refer developers to existing policies and rules by the COGCC regulating oil and gas development in the state including conserving wildlife and wildlife habitat, and to the BLM and USFS for projects being developed on federal lands. Also, reference other supportive guidelines, such as those by the Colorado Mule Deer Association and Colorado Wildlife Federation (2006).

Objective 2: Consult with the CPW, the BLM, and USFS to conserve bat habitat using land use planning.

Objective 3: Provide information to land managers and county planners about the importance of these habitats to bats and other wildlife, and conservation strategies to minimize potential impacts to their habitats.

MANAGEMENT RECOMMENDATIONS  Mitigate for fragmentation and water loss on a landscape scale by working with wetland banking programs and land trusts that purchase easements in Colorado.

RESEARCH NEEDS

 Are there different requirements for different species related to connectivity of water to habitat?

OTHER IMPACTS Bats could experience reduced fitness or increased mortality due to bioaccumulation of chemicals in insect prey (O’Shea et al. 2001; O’Shea and Johnston 2009). Fresh water storage containers could cause mortality to bats which are unable to escape accidentally falling into containers with lips higher than water level and no escape ramps. It has been documented that hydraulic fracturing can cause seismic activity (McGarr et al. 2015) which has the potential to disturb roosting bats.

GOAL REDUCE THESE POTENTIAL IMPACTS TO BATS THROUGH RESEARCH AND INFORMATION EXCHANGE. Objective 1: Refer developers to existing policies and rules by the COGCC regulating oil and gas development in the state including conserving wildlife and wildlife habitat, and to the BLM and USFS for projects being developed on federal lands. Also, reference other supportive guidelines, such as those by the Colorado Mule Deer Association and Colorado Wildlife Federation (2006).

Objective 2: Encourage research into contamination, water storage, and roost disturbance issues to determine and understand the actual impacts to bats.

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Objective 3: Disseminate relevant research to the COGCC, CPW, BLM, USFS, and developers/operators through educational workshops to assist in updating oil and gas rules as they relate to bat species.

MANAGEMENT RECOMMENDATIONS  Require closed-looped systems to limit exposure of insects or wildlife to contaminated water.  Require and maintain escape ramps for open water containers during consultation for wildlife.  Avoid development near karst regions or known subterranean habitat as specified by BLM and USFS Environmental Impact Statements.

RESEARCH NEEDS

 Are chemicals being accumulated in bats in oil and gas development areas and what are the sources? How does this affect the fitness of bats?  How often is water storage units used in current oil and gas development? Do current bat escape ramps work for water storage units?  Does hydraulic fracturing impact subterranean use by bats and how?

SOLAR POTENTIAL AND TECHNOLOGY

Due to the increasing interest to develop renewable energy alternatives, solar energy is under development throughout the United States with an emphasis in the western U.S. The US Department of Energy's (USDOE) SunShot Initiative estimates solar energy could meet 14% of U.S. electricity demand by 2030, and 27% by 2050 (USDOE 2012). In 2004, Colorado became the first state in the U.S. to adopt a renewable energy standard (RES) which has since been updated to a goal of 30% by 2020, and includes various incentives for solar energy generation (GEO 2010). Colorado currently ranks 8th in the country in Figure 8.5. Photovoltaic panels at the installed solar capacity (SEIA 2014). Government-led SunPower power plant in Alamosa County, initiatives to facilitate utility-scale solar energy Colorado. Photo by K. Navo. development on public lands include the programmatic environmental impact statement (PEIS) for solar energy by the BLM and the USDOE in 6 southwestern states, including Colorado (BLM 2010; Fig. 8.5). Under the PEIS, a total of 16,308 acres among 4 sites (solar energy zones) on BLM-administered lands in Colorado were designated for development with the potential for expansion to 95,128 acres under the preferred program alternative. In Colorado, the estimated solar energy potential is highest in the southern half of the state, especially within the San Luis Valley, which also includes the BLM-proposed solar energy zones (Figs. 8.6 and 8.7). However, the majority of utility solar development in eastern

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Colorado is currently occurring on private lands necessitating a cooperative approach with landowners and utility providers towards education and research needs related to bat interactions with solar development.

Figure 8.6. The annual average daily total solar resource available for concentrating solar arrays as estimated for Colorado between 2005-2012 (NREL, https://www.nrel.gov/gis/solar.html , Accessed December 2017). Areas depicted with the highest resource range (kWh/m2/Day) are shown in dark red and would be the most likely locations for installation of large solar arrays. Estimates are calculated as the direct normal irradiance, or the amount of solar radiation per unit area received by a surface, such as tracking photovoltaics, that keep sun perpendicular to the panel’s surface. This map was created by the National Renewable Energy Laboratory for the US Department of Energy.

The two basic methods of solar technology are photovoltaic (PV) panels and concentrating solar power (CSP). Photovoltaic panels turn sunlight directly into electricity through silicon or thin-film semiconductor material and are typically clustered into rows of panels (Fig, 8.5). Concentrating solar power technologies use heat from the sun to generate electricity and are made up of 3 main types, which include parabolic trough (Fig. 8.8), dish engine (Fig. 8.8), and power tower systems (Fig. 8.9). Direct Normal Irradiance is the amount of solar radiation received per unit area by a surface that is always held perpendicular (or normal) to the rays that come in a straight line from the direction of the sun at its current position in the sky. Typically, you can maximize the amount of irradiance annually

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received by a surface by keeping it perpendicular to incoming radiation. This quantity is of particular interest to concentrating solar thermal installations and installations that track the position of the sun.

Figure 8.7. Potential for concentrating solar resources in Colorado from 1998-2009 (Renewable Energy Laboratory, https://www.nrel.gov/gis/solar.html, Accessed December 2017).This map was created by the National Renewable Energy Laboratory for the US Department of Energy.

Figure 8.8. Parabolic trough facility in California and dish engine facility in New Mexico. Adapted from BLM (2010).

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Although wind energy accounts for the majority of bat fatalities from energy development, there is anecdotal information that solar energy may cause some direct and indirect mortality. For example, a solar energy project in Riverside County, CA found 11 bat mortalities throughout the project area over the 6 month construction period of the facility. It is unclear what caused the fatalities (Tetra Tech 2014). Bird fatalities at similar facilities have resulted indirectly from ingestion of heat transfer chemicals found in evaporation ponds. Concentrating solar power technologies might also cause direct mortality by incinerating birds and bats that pass through these areas of high heat concentration. Consequently, implementation of monitoring plans at these facilities is needed to discern the level of impact they have on bats (Tetra Tech 2014).

Figure 8.9. Power Tower facility in California. Adapted from BLM (2010).

GOAL MINIMIZE THE NEGATIVE IMPACTS OR FATALITIES TO BATS FROM SOLAR DEVELOPMENT. Objective 1: Develop mitigation funds to conduct habitat improvements beneficial to bats in areas adjacent to those lost to large solar array installations.

Objective 2: Avoid construction of solar installations that use mirrors in areas shown to have high bat activity to minimize potential for incineration or chemical contamination of individuals.

MANAGEMENT RECOMMENDATIONS  Work cooperatively with the solar industry to determine risks to bats either through behavior studies or fatality monitoring at solar facilities.  Encourage county permitting to request pre and post construction monitoring for bats at sites proposed for large solar arrays.  If collision is documented, develop guidelines to monitor and understand extent of impacts and provide guidance on avoiding important bat areas, at least until the level of impact is better understood.

RESEARCH NEEDS

 Determine the degree to which bats collide with solar structures. Develop studies to evaluate bat behavior around solar structures such as attraction to smooth surfaces (solar panels), evaporative ponds, and heat sources (concentrated solar towers).

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LITERATURE CITED API (American Petroleum Institute). 2010. Water management associated with hydraulic fracturing. API Guidance Document HF2, first edition. Washington, DC. Arnett, E. B., and E. F. Baerwald. 2013. Impacts of wind energy development on bats: implications for conservation. In Adams R., Pederson (eds) Bat Evolution, Ecology, and Conservation. Springer, New York, NY. Arnett, E. B., C. D. Hein, M. R. Schirmacher, M. M. P. Huso, and J. M. Szewczak. 2013. Evaluating the effectiveness of an ultrasonic acoustic deterrent for reducing bat fatalities at wind turbines. PLoS ONE 8:e65794-e65794. Arnett, E. B., and R. F. May. 2016. Mitigating wind energy impacts on wildlife: approaches for multiple taxa. Human-Wildlife Interactions 10:28-41. AWEA (American Wind Energy Association). 2017a. U.S. wind energy fourth quarter 2017 market report. https://www.awea.org/3q2017. AWEA (American Wind Energy Association). 2017b. Wind energy in Colorado. http://www.awea.org/Resources/state.aspx?ItemNumber=5233. Baerwald, E. F., G. H. D'Amours, B. J. Klug, and R. M. R. Barclay. 2008. Barotrauma is a significant cause of bat fatalities at wind turbines. Current Biology 18:695-696. Baerwald, E. F., J. Edworthy, M. Holder, and R. M. R. Barclay. 2009. A Large-Scale Mitigation Experiment to Reduce Bat Fatalities at Wind Energy Facilities. Journal of Wildlife Management 73:1077-1081. Bernáth, B., Szedenics, G., Molnár, G., Kriska, G., and G. Horváth. 2001. Visual ecological impact of ‘‘shiny black anthropogenic products” on aquatic insects: Oil reservoirs and plastic sheets as polarized traps for insects associated with water. Archives of Nature Conservation and Landscape Research 40(2), 89–109. BLM (Bureau of Land Management). 1994. Modification of production equipment to prevent bird and bat losses. Notice to Lessees/Operators, NTL-RDO 93-01. BLM (Bureau of Land Management). 1995. Prevention of potential bird and bat mortalities caused by production equipment design. Information Bulletin To All Federal and Indian Oil and Gas Lessee/Operators. BLM (Bureau of Land Management). 1996. Modification of oil and gas facilities to minimize bird and bat mortality. Notice to Lessees/Operators, NTL 96-01. BLM (Bureau of Land Management). 2010. Draft Programmatic Environmental Impact Statement (PEIS) for solar energy development in six southwestern states. http://solareis.anl.gov/documents/dpeis/index.cfm Carter, R. H., S. A. Holditch, and S. L. Wlohart. 1996. Results of a 1995 hydraulic fracturing survey and comparison of 1995 and 1990 industry practices. Presented at the Society of Petroleum Engineers Annual Technical Conference, Denver, CO.

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COGA (Colorado Oil and Gas Association). 2014. Energy overview. Available at: http://www.coga.org/energy-facts/. COGCC (Colorado Oil and Gas Conservation Commission). 2015. Complete rules (100-1200 Series). http://cogcc.state.co.us/documents/reg/Rules/LATEST/CompleteRules%20as%20of%20March%201 6,%202016.pdf. Colorado Mule Deer Association and Colorado Wildlife Federation. 2006. Wildlife management guidelines for oil & gas development. http://www.ourpubliclands.org/files/upload/Colorado_Oil_and_Gas_Guidelines.pdf. Conley, R. S. 2017. Bat behavior at smooth and texturized wind turbine towers. MS Thesis, Texas Christian University. Fort Worth, Texas. Cryan, P. M. 2008. Mating behavior as a possible cause of bat fatalities at wind turbines. Journal of Wildlife Management 72:845-849. Cryan, P. M., P. M. Gorresen, D. Dalton, S. Wolf, and F. Bonaccorso. 2017. Ultraviolet illumination as a means of reducing bat activity. 2017 Western Bat Working Group Meeting, Fort Collins, Colorado. Cryan, P. M., P. M. Gorreson , C. D. Hein, M. R. Schirmacher, R. H. Diehl, M. M. Huso, D. T. S. Hayman, P. D. Fricker, F. J. Bonaccorso, D. H. Johnson, K. Heist, and D. C. Dalton. 2014. Behavior of bats at wind turbines. Proceedings of the National Academy of Sciences of the United States of America 111:15126–15131. EERE (Energy Efficiency and Renewable Energy, Office of). 2014a. “Wind energy technology basics” http://energy.gov/eere/energybasics/articles/wind-energy-technology-basics EERE (Energy Efficiency and Renewable Energy, Office of). 2014b. “Wind Turbine basics” http://energy.gov/eere/energybasics/articles/wind-turbine-basics Entrekin, S., M. Evans-White, B. Johnson, and E. Hagenbuch. 2011. Rapid expansion of natural gas development poses a threat to surface waters. Frontiers in the Ecology and Envronment 9:503–511. Esmoil, B. J, and S. H. Anderson. 1995. Wildlife mortality associated with oil pits in Wyoming. Prairie Naturalist 27(2):81-88. Finley, R. B., Jr., W. Caire, and D. E. Wilhelm. 1983. Bats of the Colorado oil shale region. Great Basin Naturalist 43:554-560. GEO (Governor's Energy Office). 2010. Colorado’s 30% Renewable Energy Standard: Policy Design and New Markets. 11 pp. Gorresen, P. M., P. M. Cryan, D. C. Dalton, S. Wolf, and F. J. Bonaccorso. 2015. Ultraviolet Vision May be Widespread in Bats. Acta Chiropterologica 17:193-198. GWPC (Ground Water Protection Council) and All Consulting. 2009. Modern shale gas development in the US: A primer. Contract DE-FG26-04NT15455. Washington, DC. US Department of Energy, Office of Fossil Energy and National Energy Technology Laboratory.

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Hammerson, G. A., M. Kling, M. Harkness, M. Ormes, and B. E. Young. 2017. Strong geographic and temporal patterns in conservation status of North American bats. Biological Conservation 212:144- 152. Hein, C. D. 2012. Potential impacts of shale gas development on bat populations in the northeastern United States. An unpublished report submitted to the Delaware Riverkeeper Network, Bristol, Pennsylvania by Bat Conservation International, Austin, Texas. Horvath, G., and J. Zeil. 1996. Kuwait oil lakes as insect traps. Nature 379: 303-304. Lindsey, C. T. 2017. Evaluating the effectiveness of an acoustic deterrent on north Texas bat species. MS Thesis, Texas Christian University. Fort Worth, Texas. Makani. 2014. “The technology: Meet the energy kite” http://www.google.com/makani/technology/ McGarr, A., B. Bekins, N. Burkardt, J. Dewey, P. Earle, W. Ellsworth, S. Ge, S. Hickman, A. Holland, E. Majer, J. Rubinstein, and A. Sheehan. 2015. Coping with earthquakes induced by fluid injection. Science 347(6224):830-831. O'Shea, T. J., and J. J. Johnston. 2009. Environmental contaminants and bats; investigating exposure and effects. Pp. 500-528 in Ecological and behavioral methods for the study of bats (Kunz and Parsons eds). The Johns Hopkins University Press. Baltimore, Maryland. O'Shea, T. J., A. L. Everette, and L. E. Ellison. 2001. Cyclodiene insecticide, DDE, DDT, arsenic, and mercury contamination of big brown bats (Eptesicus fuscus) foraging at a Colorado superfund site. Archives of Environmental Contamination & Toxicology 40:112-120. O'Shea, T. J., P. M. Cryan, D. T. S. Hayman, R. K. Plowright, and D. G. Streicker. 2016. Multiple mortality events in bats: a global review. Mammal Review 46:1-16. Ramirez, P. 1999. Fatal attraction: oil field waste pits. Endangered Species Bulletin 104:10-11. Ramirez, P. 2000. Wildlife mortality risk in oil field waste pits. Contaminants Information Bulletin. US Fish and Wildlife Service, Region 6. Ramirez, P. and S. B. Mosley. 2015. Oil and gas wells and pipelines on US wildlife refuges: challenges for managers. PLoS ONE 10(4):1-16. Riley, T. Z., E. M. Bayne, B. C. Dale, D. E. Naugle, J. A. Rodgers, and S.C. Torbit. 2012. Impacts of crude oil and natural gas developments on wildlife and wildlife habitat in the Rocky Mountain region. The Wildlife Society Technical Review 12–02. Bethesda, Maryland: The Wildlife Society. http://wildlife.org/wp-content/uploads/2014/05/Oil-and-Gas-Technical-Review_2012.pdf. Rollins, K. E., D. K. Meyerholz, G. D. Johnson, A. P. Capparella, and S. S. Loew. 2012. A Forensic Investigation Into the Etiology of Bat Mortality at a Wind Farm: Barotrauma or Traumatic Injury? Veterinary Pathology 49:362-371. Satterfield, J., D. Kathol, M. Mantell, F. Hiebert, R. Lee, and K. Patterson. 2008. Managing water resource challenges in select natural gas shale plays. GWPC Annual Forum. Oklahoma City, OK: Chesapeake Energy Corporation.

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Schwab, N. A. and K. DuBois. 2006. Bat Conservation Plan and Strategy for Montana. Draft (September 2006). Montana Bat Working Group. 133 pp. SEIA (Solar Energy Industries Association). 2014. Colorado Solar. https://www.seia.org/state-solar- policy/colorado-solar (Accessed March, 2018) Tetra Tech. 2014. Revised Bird and Bat Conservation Strategy: Genesis Solar Energy Project Eastern Riverside County, California. http://docketpublic.energy.ca.gov/PublicDocuments/09-AFC- 08C/TN201879_20140317T152343_Genesis_Solar_BBCS.pdf (Accessed December, 2017). Trail, P. 2006. Avian mortality at oil pits in the United States: a review of the problem and efforts for its solution. Environmental Management 38:532-544. USDOE (US Department of Energy). 2012. SunShot Vision Study. 292. pp. USEIA (US Energy Information Administration). 2012. Annual energy outlook 2012 early release overview. Report No. DOE/EIA-0383ER(2012). Accessed February 2012. http://www.eia.gov/forecasts/aeo/er/pdf/0383er(2012).pdf. USFWS (US Fish and Wildlife Service). 2009. Migratory bird mortality in oilfield wastewater disposal facilities. http://www.fws.gov/mountain- prairie/contaminants/documents/COWDFBirdMortality_000.pdf. Warner, K. A. 2016. Investigating the effects of noise pollution from energy development on the bat community in the Piceance Basin. Colorado State University, Fort Collins, Colorado. Winter, T. C., J. W. Harvey, O. L. Franke, and W. M. Alley. 1998. Ground water and surface water: A single resource. US Geological Survey Circular, 1139, 1–78.

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IX. GUIDANCE FOR SCIENTIFIC ACTIVITIES

By Kirk W. Navo and Daniel J. Neubaum

Our knowledge of the natural history of bat species is less comprehensive than that of most other groups of mammals in Colorado. This lack of knowledge is due in part to the difficulties in the observation and identification of bats. Bats are small, nocturnal mammals that are generally silent to the human ear, and very mobile due to their flight abilities. In our efforts to learn more about bats, the development of research techniques continues to rely heavily on new technologies. Some techniques have adversely impacted individuals or significant portions of bat populations such improper banding techniques. Both field and lab techniques disturb bats to some degree and every attempt should be made to develop research techniques that maximize the collection of appropriate data while minimizing impacts to the bats.

We address four categories of scientific activities commonly used to study bats that have potential to negatively affect these animals: research, inventory, and monitoring at roosts; trapping and handling; marking; and telemetry.

RESEARCH, INVENTORY AND MONITORING

A number of guidelines and protocols have been developed to assist with the research, inventory, and monitoring of bats in Colorado. Any work proposing to capture and/or handle bats in Colorado requires a scientific collection permit from Colorado Parks and Wildlife (CPW). Each permit will include stipulations dealing with bat specific concerns that must be followed. CPW has also developed bat capture and handling guidelines that detail the use of acceptable techniques as well as standards and expectations (Neubaum and Jackson 2016).

GOAL FOLLOW ESTABLISHED TECHNIQUES AND PROTOCOLS FOR RESEARCH, INVENTORY, AND MONITORING AT ROOSTS. Objective 1: Monitoring of maternity roosts should be conducted by external evening exit counts when possible. The use of thermal and infrared imaging equipment is recommended to attain more accurate counts. Passive techniques such as acoustic recordings may also be useful. In Colorado, counts should be conducted from late May–late June, after the entire colony has returned to the roost but 1–2 weeks prior to parturition of the species. This “window” may vary by elevation, with higher sites in the mountains starting several weeks later than desert and plains locations. The roost may require several visits for this window to be ascertained. Roost counts in future years should be conducted as close to the same dates as possible. See Kunz et al. (2009) for a detailed discussion of

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techniques recommended for counting maternity colonies and other roosts. Navo (2001) provides additional information for conducting such work at abandoned mines.

Because maternity roosts can be sensitive to disturbance, they should not be entered unless absolutely necessary. Under no conditions should animals be removed from or disturbed in a nursery cluster unless approved by an animal care and use committee. Harp traps should be used when capturing bats at maternity Thermal imaging used to conduct exit counts at mine roost entrances. Any netting of bats at entrance. Photo by D. Neubaum. these roosts should be conducted outside the roost and away from the roost entrance when possible.

Objective 2: Because of the possible negative impacts of disturbance to hibernating bats, monitoring at hibernating sites should be kept to a minimum. Hibernacula should not be entered more than once every 2–3 years unless absolutely necessary. Surveys should be conducted as quickly and quietly as possible (Navo 2001).

TRAPPING AND HANDLING

Trapping is fundamental to many inventories and research studies. Species identification is difficult for Myotis spp. without handling individuals, and bats must be captured for markings or telemetry to be affixed. Trapping methods have improved substantially over the years, but all methods can adversely affect bats if done incorrectly. Bats can be captured during emergence from roosts, and while foraging or drinking away from roosts. Of these, capturing bats away from roost sites while they are foraging or drinking is expected to cause the least disturbance. Bats will often switch roosts (often to lesser-quality sites) in response to trapping at the primary roost. More significantly, capture during hibernation or lactation disrupts critical energy budgets required for these life stages. The proposed research question will often determine when trapping and handling occurs but it is important to understand the anticipated response of bats to these activities during different seasons. Hand capture, hand nets, bucket traps, bag and funnel traps, mist nets Bat caught in mist net. and harp traps all pose a risk of direct injury to bats. All trapping Photo by D. Neubaum. methods share the common issue of causing stress to the individuals

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captured. In addition to these risks, the onset of White-nose syndrome (WNS) in North America has created a situation where trapping and handling bats may expose uninfected individuals to the disease. More detailed information on trapping and handling can be found in Neubaum and Jackson (2016) and Kunz et al. (2009).

GOAL MINIMIZE STRESS AND DISEASE TRANSFER TO BATS BY ENSURING THAT ALL FIELD STAFF HAVE RECEIVED THOROUGH TRAINING ON CAPTURE AND HANDLING METHODS. Objective 1: Follow standard bat trapping and handling protocols, such as the CPW Bat capture and handling guidelines, to minimize disease transmission, disruption and stress to bats.

Objective 2: Encourage the Colorado Bat Working Group to host bat trapping workshops that educate researchers.

Objective 3: Encourage the use of passive techniques such as acoustic detectors where feasible.

Objective 4: Implement US Fish and Wildlife Bat marked with glow tag. Photo by K. Keisling. Service (USFWS) WNS decontamination measures, as required by CPW permit stipulations, to ensure that capturing and handling bats does not spread diseases (see https://www.whitenosesyndrome.org/topics/decontamination for USFWS Decontamination Protocol).

RESEARCH NEEDS

 Develop new trapping techniques that minimize stress on bats.

MARKING

Marking bats is typically used to study general population dynamics and movement patterns. All marking techniques have the potential to affect the survival of the bats under study. The use of metallic and plastic bands has been borrowed from techniques developed for birds and has been employed since the 1940s. More recent marking techniques include the use of necklaces (made of either beaded keychains or plastic ratchet loops) and Passive Integrated Transponder (PIT) tags. Additionally, light marking of individuals to study real-time movement patterns has employed Light Emitting Diodes (LED), reflective tape, and chemiluminescent and Betalight markers.

All of these marking techniques require the capture and handling of bats which can alter their energy budgets, cause roost-site abandonment, and stress animals. Metallic bands, PIT tags and necklaces can

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affect mobility and even cause direct injury if inappropriately applied, and bats must be recaptured either in hand or by a PIT reader to determine identity. Plastic bands and light tagging/marking techniques help minimize the need for recapture, but still may affect mobility, cause wing damage, and increase predation. More detail can be found on all of the marking techniques in the CPW Bat capture and handling guidelines (Neubaum and Jackson 2016) as well as Kunz and Weise (2009).

GOAL MINIMIZE IMPACTS TO BATS USED IN RESEARCH BY REFINING CURRENT MARKING METHODS WHERE NECESSARY AND DEVELOPING LESS INVASIVE TECHNIQUES. Objective 1: Limit the banding of bats to necessary and justified research proposals. Due to past problems associated with banding of some species, banding studies will need to provide good justification with clear and obtainable objectives to CPW when applying for a scientific collection permit. Banding of bats should only be conducted by experienced bat biologists, preferably using lipped bands. Band numbers and banding locations must be documented and provided to CPW for future reference. Widespread and indiscriminate banding of bats is discouraged. Banding of a large percentage of any one colony is discouraged and should not be permitted unless accompanied by clear scientific objectives that harm to bats will be limited.

Objective 2: Work with bat researchers to target less-sensitive bat populations for studies.

Objective 3: Encourage the use of marking techniques such as PIT tags that limit the need for recapture of individuals. Share techniques and improvements so that others are aware of pros and cons of methods.

Objective 4: Encourage use of developed protocols that minimize adverse effects from PIT tag reader and antenna outside of mine marking bats (see CPW Bat capture and handling entrance to detect bats that have had PIT tags guidelines). implanted. Photo by D. Neubaum.

RESEARCH NEEDS

 Develop less invasive marking techniques.  Investigate analytical methods that minimize the need to mark individuals.

TELEMETRY

Radio-transmitter technology has allowed researchers to learn about movement patterns and roosting behavior for most North American bat species. Keeping transmitter-to-bat body weight ratios below 5%

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(Aldridge and Brigham 1988) has been shown to minimize adverse effects to bat movements and has been shown not to affect long-term survival (Neubaum et al. 2005) for some species. This weight limitation is often accomplished by using smaller, shorter lived batteries which makes tracking of bats, particularly those migrating, less successful. In addition, these transmitter weight limits restrict what knowledge is collected on smaller species, such as Myotis and Parastrellus. It is currently unknown if bats can accommodate heavier radio transmitters as few studies have exceeded the “5% rule” and included long-term tracking of individuals.

Objective 1: Encourage use of the “5% rule” for all bat radio work.

Objective 2: Recommend that bat research using radio-transmitters Bat with radio transmitter. at levels exceeding 5% of body mass only do so if they are able to Photo by D. Neubaum. also track long-term survival.

RESEARCH NEEDS

 Evaluate the long term survival and condition for radio tracking species inhabiting heavily cluttered areas where maneuverability and high energetic demands are a concern.  Design a research study to test long-term survival and condition of bats where radio-transmitter size exceeds the “5% rule”.

LITERATURE CITED Aldridge, H. D. J. N., and R. M. Brigham. 1988. Load carrying and maneuverability in an insectivorous bat: a test of the 5% "Rule" of radio-telemetry. Journal of Mammalogy 69:379-382. Kunz, T. H., R. Hodgkinson, and C. D. Weise. 2009. Methods of capturing and handling bats. Pp. 3-35 in T.H. Kunz and S. Parsons, editors. Ecological and behavioral methods for the study of bats. The Johns Hopkins University Press, Baltimore, MD. Kunz, T. H., and C. D. Weise. 2009. Methods and devices for marking bats. Pp. 36-56 in T.H. Kunz and S. Parsons, editors. Ecological and behavioral methods for the study of bats. The Johns Hopkins University Press, Baltimore, MD. Navo, K. W. 2001. The survey and evaluation of abandoned mines for bat roosts in the West: guidelines for resource managers. Proceedings of the Denver Museum of Nature and Science, Series 4, Number 2:1-12. Neubaum, D. J., M. A. Neubaum, L. E. Ellison, and T. J. O'Shea. 2005. Survival and condition of big brown bats (Eptesicus fuscus) after radiotagging. Journal of Mammalogy 86:95-98. Neubaum, D. J., and T. S. Jackson. 2016. Bat capture and handling guidelines. Colorado Parks and Wildlife, ACUC 04_2016, Denver, CO.

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X. CONSIDERATIONS FOR BAT ROOST PROTECTION

By Kirk W. Navo and Daniel J. Neubaum

The protection of bat roosts is one of the most important issues when considering bat conservation (Pierson 1998). Destruction and disturbance of bat roost sites, especially caves, has been a notable contributor to the decline of bat populations in the US and around the world (Mohr 1972; Humphrey 1975; McCracken 1989; O'Shea et al. 2016). Conservation of roosts is more important now than ever before with the risk of human activity spreading White-nose syndrome (WNS) between sites. The abandonment of roosts by bats may result from human disturbance, direct loss of roosts from closures of the site or eviction of bats, destruction, or natural events. Human disturbance by the public, resource managers, or researchers can have negative impacts on bats using any given roost site. This is especially true at winter hibernacula, where more frequent arousals by hibernating bats can lead to the loss of fat reserves before spring arrival. Sheffield et al. (1992) provides several useful guidelines for the protection of bat roosts. Review this issue in the various chapters for more specific information related to the different roosting habitats and related conservation recommendations. In general, guidelines can include:  Avoid revealing exact locations of bat roosts to the general public.  Limit access to critical bat roosts to state, federal, or academic researchers with validated goals and valid permits.  Follow WNS decontamination protocols when working at roost sites.  Avoid or minimize disturbances within a roost.  Research should be discontinued or minimized while bats are hibernating, and focused on early or late time periods of the hibernation season.  Collections of specimens should be minimal and should occur outside the roost instead of inside.  Proper gating guidelines should be followed when bat gates are installed at caves or abandoned mines.  Exclusions, when necessary, should be conducted following appropriate guidelines and seasonal considerations, and potential alternative roosts should be considered and evaluated in the process. There are numerous ways to protect bat roosts. These include various bat-friendly closures (bat- compatible gates, cages or cupolas, gated culverts, cable nets, half-gates, perimeter fences, and seasonal closures), buffer zones, climbing regulations, and cave registers or permit requirements. We discuss several of the most commonly implemented alternatives below. Not all roosts are created equal. Some roosts carry greater levels of importance to the local bat populations associated with them. Making decisions regarding which roosts deserve protection can be difficult. Guidelines for determining which roosts are considered biologically important to helping sustain local bat populations have been created (Neubaum et al. 2017) and may be found on the Colorado Bat Working Group (CBWG) website: http://www.cnhp.colostate.edu/cbwg/. In addition, the threats affecting roosts may vary depending on

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the bat species under consideration. The CBWG created a user friendly threat matrix that can be queried on a species or threat basis. See chapter XII. Assessing Threats to Bat Species: The Colorado Bat Matrix, for a detailed description of the threat matrix tool and visit the interactive website at: http://www.cnhp.colostate.edu/batmatrix/. We address four categories of issues that should be considered when protecting bat roosts: bat-compatible gates; buffer zones; seasonal closures; and exclusions.

BAT-COMPATIBLE GATES

Gates have been used extensively in the eastern US for more than 30 years to protect critical cave roosts. However, if these gates are not bat-compatible, or if they modify the microclimate of the roost, they may actually pose a threat to bats (Tuttle 1977; White and Seginak 1987; Richter et al. 1993; Pugh et. al. 2005; Spanjer and Fenton 2005). Bat gate installation involves a number of important considerations:  Learn the special needs of the bats using the mine or cave to be gated. Factors such as species of bat, colony size, season of use, roost type, cave/mine configuration, and other aspects will determine what type of gate to install. Gate types can include angle iron full gates, culvert gates, ladder gates, cupolas, half-gates, and slot gate designs. Knowledgeable specialists from Colorado Parks and Wildlife (CPW), Colorado Committee of the Western Bat Working Group, Bat Conservation International (BCI), or other local bat specialists with experience on the subject can be consulted to determine optimum gate design for a specific closure (also see Sheffield et al. 1992; Pierson et al. 1999; Ludlow and Gore 2000; Navo and Krabacher 2002; Navo and Krabacher 2005).  Provide an adequate flyway for bats emerging from the roost while also allowing for effective exclusion of human intruders. Current approved bat gate designs call for 5¾ inch spacing between horizontal bars and a minimum of 2 feet between upright posts. Some designs call for 4 inch spacing between horizontal bars in the lower 3 feet of the gate to absolutely preclude children and small adults. This spacing is advisable with gates near human dwellings and high potential visitation. Materials and gate designs are factors in spacing.  Minimize restriction and alteration of the overall mine or cave opening and surface interface in order to limit alteration of the microclimate within the roost (e.g., temperature, humidity, and airflow). This microclimate is critical to the quality of habitat provided by the roost (Tuttle 1977; Richter et al. 1993).  Determine seasons of bat use and plan gate installation at a time when the bats are not present, or at a time that will cause minimal disturbance to the resident bats.  Design the closure for maximum security and resistance to vandalism, considering such parameters as the mine or cave’s geology, proximity to populated areas, and degree of visitation.  Prioritize roosts for gating when necessary, considering human health and safety, preservation of sensitive species, and cost.

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 Procure funding and landowner consent for bat gates on private lands.  Conduct public outreach programs to agencies, industry, and private landowners to promote bat-compatible closures where they are warranted.  A monitoring program should be part of any gating program. This is especially important when modifications to traditional gate designs are used, and before wide-spread use of such modifications are implemented to ensure continued bat use of roost sites. Specific designs for bat-compatible gates can be found in Navo and Krabacher 2005, Fant et al. (2009), Pierson et al. (1999), and Tuttle and Taylor (1998).

BUFFER ZONES

Buffer zones may be useful in protecting bat roosts (Elliott 2012). Policies were developed to protect caves on federal lands in 1994 by the Deschutes National Forest and the Oregon and Washington Bureau of Land Management (BLM). Included in the recommendations were a number of policies to protect bat habitat. On lands administered by the BLM, "no new surface disturbing activities would be authorized within a 350 foot radius of a cave opening or any known cave passages which may adversely impact any significant or potentially significant cave resource value." On the national forest, trees are not to be harvested within a 150–200 foot radius of cave entrances and infeeder drainages where slopes are less than 30 degrees. On slopes steeper than 30 degrees next to cave entrances, ground-disturbing activities are prohibited. Clear-cutting is not allowed within 250 feet of caves with significant bat populations. Forested corridors between cave entrances and nearest foraging areas are to be maintained at a 150– 200 foot radius. If the nearby foraging area is a stream, then trees are not to be harvested 75–100 feet on either side. Hoosier National Forest in Indiana uses a similar 150–200 foot radius buffer around cave entrances and infeeder drainages. On the Tongass National Forest in Alaska, surface disturbing activities are restricted a minimum of 100 feet from the edge of any karst feature (e.g., sinkhole, collapsed channel, stream infeeder, or cave) if associated groundwater contributes to a significant cave, stream or domestic water supply. No surface disturbing activity will occur on land directly overlying any known significant cave or waters contributing to the cave (USFS 1996). Pierson et al. (1999) provides for more generous buffers than the above agencies. They suggest a buffer zone of 2 miles around all Townsend’s big-eared bat (Corynorhinus townsendii) roost sites for pesticide spraying. They also recommend no prescribed burning or vegetative alteration in shrub-steppe or pinyon/juniper habitats within a 1.5 mile radius of C. townsendii roost sites. For forested habitat, no more than half can be subjected to prescribed burning per decade within a 0.5 mile radius of the roost site and only when bats are not present. For timber harvesting they suggest maintaining a buffer zone of 500 feet (horizontal radius) around all roost entrances.

SEASONAL CLOSURES

Another useful protective measure for bat roosts is seasonal closures. Seasonal closures can be used

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during critical time periods such as maternity or hibernation periods. A general guide for seasonal closures suggested by Pierson et al. (1999) and Navo (2001) is to close caves used for hibernacula to recreational visitor use from October 15–April 15, close maternity caves from April 15–August 31, and swarming sites from September 1–October 15. These critical time periods of hibernation, swarming, and maternity activity may vary regionally and need to be determined by a qualified biologist. There will also be site-specific flexibility to seasonal closures. Seasonal closures can be considered on climbing activities or any other recreational activity in and around roost sites.

EXCLUSIONS

Prior to closure work at winter/fall roosting sites that will not have a bat gate installed; exclusion of bats may be recommended. The exclusion is intended to help prevent the entry and use of the site by bats, and prevent the trapping of bats inside the reclaimed mine feature. This would involve screening out bats by placing chicken wire (1 inch mesh or more) across the entire opening, as well as any un-gated but open access point to the mine complex. The exclusion effort should take place a minimum of 3 nights/days prior to the start of any construction activities. Longer periods of time (i.e., 1 week) are appropriate, if possible. The chicken wire should cover the opening from the top to about 5-6 inches from the floor or bottom of the opening. This will help prevent bats from entering the mine, and also allow any bats that may be inside the mine prior to the exclusion effort, to escape for the mine before the closure operations begin. This would suggest that exclusions begin by September 1 at these fall/winter sites. They can go up at any time prior to the start of the fall transition season, but no later than September 30, to avoid weather related variations to fall bat activity. In addition, exclusions are not considered functional from October 1 – April 15, because reduced activity of bats.

LITERATURE CITED Elliott, W. R. 2012. Protecting Caves and Cave Life. Pages 624-633 in W. B. White, andD. C. Culver, editors. Encyclopedia of Caves. Elsevier, Inc,Burlington, VT. Fant, J., J. Kennedy, R. Powers Jr., and W. Elliott. 2009. Agency guide to cave and mine gates. Bat Conservation International, Austin, TX. Humphrey, S. R. 1975. Nursery roosts and community diversity of Nearctic bats. Journal of Mammalogy 56:321-346. Ludlow, M. E., and J. A. Gore. 2000. Effects of cave gate on emergence patterns of colonial bats. Wildlife Society Bulletin 28:191-196. McCracken, G. F. 1989. Cave conservation: special problems of bats. Bulletin of the National Speleological Society 51:49-51. Mohr, C. E. 1972. The status of threatened species of cave-dwelling bats. Bulletin of the National Speleological Society 34:33-47. Navo, K. W. 2001. The survey and evaluation of abandoned mines for bat roosts in the West: guidelines for resource managers. Proceedings of the Denver Museum of Nature and Science, Series 4,

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Number 2:1-12. Navo, K. W., and P. Krabacher. 2002. Bat Ladder Gates. In Bat Gate Design: A Technical Interactive Forum. Proceedings. March 4-6, 2002. Austin, Texas. (K. C. Vories and D. Throgmorton, eds.) Southern Illinois University, Carbondale. Navo, K. W., and P. Krabacher. 2005. The use of bat gates at abandoned mines in Colorado. Bat Research News. Vol.46: No.1. Pg 1-8. Neubaum, D. N., K. W. Navo, and J. L. Siemers. 2017. Guidelines for Defining Biologically Important Bat Roosts: A Case Study from Colorado. Journal of Fish and Wildlife Management 8:272-282. O'Shea, T. J., P. M. Cryan, D. T. S. Hayman, R. K. Plowright, and D. G. Streicker. 2016. Multiple mortality events in bats: a global review. Mammal Review 46. Pierson, E. D. 1998. Tall trees, deep holes, and scarred landscapes. Pages 309-325 in T. H. Kunz, and P. A. Racey, editors. Bat Biology and Conservation. Smithsionian Institution Press,Washington. Pierson, E. D., M. C. Wackenhut, J. S. Altenbach, P. Bradley, P. Call, D. L. Genter, C. E. Harris, B. L. Keller, B. Lengus, L. Lewis, B. Luce, K. W. Navo, J. M. Perkins, S. Smith, and L. Welch. 1999. Species Conservation Assessment and Strategy for Townsend's Big-eared Bat (Corynorhinus townsendii townsendii and Corynorhinus townsendii pallescens). Idaho Conservation Effort, Idaho Department of Fish and Game, Boise, Idaho. 68 pp. Pugh, M., and J. D. Altringham. 2005. The effect of gates on cave entry by swarming bats. Acta Chiropterologica, 7(2): 293-299. Richter, A. R., S. R. Humphrey, J. B. Cope, and V. Brack, Jr. 1993. Modified cave entrances: thermal effect on body mass and resulting decline of endangered Indiana bats (Myotis sodalis). Conservation Biology 7:407-415. Sheffield, S. R., J. H. Shaw, G. A. Heidt, and L. R. McClenaghan. 1992. Guidelines for the protection of bat roosts. Journal of Mammalogy 73:707-710. Spanjer, G. R., and M. B. Fenton. 2005. Behavioral responses of bats to gates at caves and mines. The Wildlife Society Bulletin 33(3):1101-1112. Tuttle, M. D. 1977. Gating as a means of protecting cave dwelling bats. Pp. 77-82 in National Cave Management Symposium. Proceedings (T. Aley and D. Rhodes, eds.). Speleobooks, Albuquerque, New Mexico. Tuttle, M. D., and D. A. R. Taylor. 1998. Bats and mines (revised edition). Bat Conservation International, Resource Publication No. 3. USFS (US Forest Service). 1996. Revised Supplement to the Draft EIS, Tongass Land Management Plan Revision. Tongass National Forest. Alaska. White, D. H., and J. T. Seginak. 1987. Cave gate designs for use in protecting endangered bats. Wildlife Society Bulletin 15:445-449.

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XI. SPECIES STATUS, POPULATION TRENDS, AND MONITORING

By Kirk W. Navo, Daniel J. Neubaum, and Jeremy L. Siemers

Too little is currently known about basic biology and ecology of most species of bats in Colorado to provide evaluations of their status and population viability. While some work over the last 20 years has helped elucidate general distributions and protected some colonies across the state, there remain many questions and information gaps. Monitoring of bats presents many challenges to resource managers and researchers (see O’Shea and Bogan 2003, “Monitoring Trends in Bat Populations of the United States and Territories: Problems and Prospects” at https://pubs.usgs.gov/itr/2003/0003/report.pdf; Neubaum et al. 2017, http://www.cnhp.colostate.edu/cbwg/), yet estimating trends in bat populations is vital to preserving the biological diversity of Colorado. Understanding changes in populations is especially important for those species listed by the NatureServ/Colorado Natural Heritage Program (Master et al. 2012), most of which were formerly considered Category 2 candidates under the Endangered Species Act (ESA; USFWS 1994), to prevent the future need for listing as state or federal threatened or endangered species. In addition to these rankings, the State Wildlife Action Plan developed by Colorado Parks and Wildlife (CPW) lists 4 Tier 1 and 3 Tier 2 bat species that are considered to have some level of concern for their conservation in the state (CPW 2015). The following list of management projects, data gaps, and research needs is intended to help guide and focus the limited resources available for bat conservation in Colorado. These projects would provide valuable information to determine species status, and would help develop the tools required to monitor population trends and implement future conservation actions. Projects are not presented in order of priority but are grouped by subject matter.

DISEASE

 Research the diversity and distribution of fungi naturally occurring on bats in Colorado for White-nose syndrome (WNS) related planning and surveillance.  Evaluate the potential of acoustic approaches to monitoring of bats at hibernacula and swarming sites for WNS surveillance.  Develop survival estimates for all species whose populations are thought to be most vulnerable to declines from WNS in Colorado.

 Investigate the bacterial microbiota native to Bat with White-Nose Syndrome. Photo by S. Colorado bat species to see if some inhibit Taylor.

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fungal growth of Pseudogymnoascus destructans, such as Streptomyces (Hamm et al. 2017; Winter et al. 2017).  Search for novel diseases carried by Colorado bats that currently have not been described.

CAVES AND MINES

 Provide a comprehensive evaluation of bat gates installed on caves and mines in Colorado.  Complete the inventory of caves to identify and protect important bat colonies, especially in areas with high densities of significant cave and karst formation (such as the White River National Forest)  Continue to survey, identify, and protect important bat roosts in abandoned mines on public and private lands in cooperation with active state and federal Abandoned Mine Lands closure programs.  Determine the importance of caves and mines to hibernating bat populations.  Evaluate potential impacts from high radon concentrations (>100 pCi/L) to bats roosting in uranium mines.

 Determine the extent and importance of Cave hibernacula. Photo by D. Neubaum. “swarming” by bats at caves and mines.

ROOSTS

 Determine the winter roost status of all bat species thought to hibernate in the state.  Determine the winter roost status for Brazilian free-tailed (Tadarida brasiliensis), and silver- haired bats (Lasionycteris noctivagans), presumed to be migratory.  Evaluate winter bat activity at locations not traditionally investigated, such as talus slopes, canyons, and cliff faces.  Search for and document maternity roosts and hibernacula for all bat species listed in the CPW State Wildlife Action Plan, and federal agency sensitive species lists (see Table 11.1 and Section XIII. Species Accounts).  Evaluate the amount of roost switching by maternity colonies of Colorado bat species, and determine the distances moved, the frequency of switching, and factors that trigger such movements.  Evaluate the seasonal movements of Colorado bat species between summer nurseries and winter hibernacula, and define population units for conservation.  Evaluate the potential of impacts to bats roosting in crevices by recreational climbing.

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 Characterize rock crevice roosts used by bats and differentiate seasonal variation of microclimates at these roosts.  Evaluate the use and importance of bridges as roost sites for bats in Colorado.  Develop predictive occurrence maps for winter use by bats in Colorado to help guide future searches of hibernacula.  Determine the types of seasonal roosts utilized by all species of concern, and the importance of each type of roost to long-term survival of each species.  Investigate the use and importance of man-made structures used as roosts by species of concern.  Determine the extent of “swarming” by bats at sites other than caves and mines in Colorado.  Verify the roosting requirements of tree roosting bats, as reported from research elsewhere, in Colorado’s forests.  Evaluate the potential of using artificial roosts in areas where the loss of natural roosts has been documented, and may be limiting population recovery.  Evaluate the value of artificial bat houses in Colorado, and the potential role they could play in urban settings.  Evaluate the potential of acoustic approaches to monitoring bats at important roost sites.  Continue to develop new techniques and equipment to allow less intrusive monitoring of bat colonies.  Develop long-term monitoring programs for the Brazilian free-tailed bat bachelor colony at the Orient Mine in the San Luis Valley (the largest bat roost in Colorado), and the maternity colony in Grand Junction.  Establish monitoring programs for selected colonies of bat species listed in the CPW State Wildlife Action Plan, and federal agency sensitive species lists (see Table 11.1 and Section XIII. Species Accounts).

SPECIES STATUS

 Develop accurate range maps for all Colorado bat species.  Determine the status of tri-colored bats (Perimyotis subflavus) in eastern Colorado.  Determine the status of eastern red bats (Lasiurus borealis) in eastern Colorado.  Determine the status of cave myotis (Myotis velifer) in southeastern Colorado.  Determine the status of Allen’s big-eared bats (Idionycteris phyllotis) in western Colorado.  Determine if acoustic records of western red bats (Lasiurus blossevillii) collected in western Colorado are misclassified or if the species actually occurs there.  Determine the status of big free-tailed bats (Nyctinomops macrotus) in Colorado.  Determine the winter status of spotted bats (Euderma maculatum) in Colorado.  Establish an acoustic bat call library for Colorado, which is essential to document local distribution and foraging behavior of bats.

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ENERGY

 Evaluate the extent to which wind energy development is impacting migrating bats in Colorado.  Evaluate the potential impacts of large-scale solar energy development to bats in Colorado.  Investigate the potential for entrapment and accumulation of contaminants by bats using oil and gas evaporative ponds.

Wind farm on public lands. Photo by C. Cryan.

MIGRATION

 Investigate seasonal migrations in elevation, rather than latitude, which may be used by many bat species in Colorado.  Determine migratory patterns and important flyways of migratory bat species in Colorado. If important migratory corridors and flyways have already been identified, establish methods to protect, maintain, restore if necessary, and monitor them.  Encourage and initiate interstate and international communication and coordination for conservation of our migratory bats, especially the Brazilian free-tailed bat. Explore the potential of a bat conservation partnership with bird conservation efforts (Partners In Flight)

Little brown myotis with radio transmitter attached. Photo by K. Keisling.

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Table 11.1. Status of Colorado bat species as ranked by NatureServe and the Colorado Natural Heritage Program (NatureServ/CNHP), The Colorado Parks and Wildlife State Wildlife Action Plan (SWAP), Colorado Bureau of Land Management (BLM), Region 2 of the US Forest Service (USFS), and the US Fish and Wildlife Service (USFWS) as of December 2017. Conservation status of bat species, as defined by NatureServe, is ranked on a scale of 1–5 as follows: critically imperiled (G1), imperiled (G2), vulnerable (G3), apparently secure (G4), and demonstrably secure (G5). Assessment and documentation of status occurs at 3 geographic scales: global (G), national (N), and state/province (S). State Wildlife Action Plan ranks include Tier 1 for species of highest conservation priority and Tier 2 for species whose listing status is of concern but the urgency of action is deemed to be less. BLM and USFS rankings are given for sensitive species (SS) only as no threatened or endangered bat species currently exist in their management boundaries. Common Name Scientific Name NatureServe/CNHP SWAP CPW BLM USFS USFWS Allen’s big-eared bat Idionycteris phyllotis G4 S1 Tier2 SS Big brown bat Eptesicus fuscus G5 S5 Big free-tailed bat Nyctinomops macrotis G5 S1 Tier 2 SS Brazilian free-tailed bat Tadarida brasiliensis G5 S1 California myotis Myotis californicus G5 S3 Canyon bat Parastrellus hesperus G5 S4 Eastern red bat Lasiurus borealis G3G4 S2S3B Fringed myotis Myotis thysanodes G4 S3 Tier 1 SS SS Hoary bat Lasiurus cinereus G3G4 S3S4B Tier 2 SS Little brown myotis Myotis lucifugus G3 S4 Tier 1 Long-eared myotis Myotis evotis G5 S4 Long-legged myotis Myotis volans G4G5 S5 Pallid bat Antrozous pallidus G4 S4 Silver-haired bat Lasionycteris noctivagans G3G4 S3S4 Spotted bat Euderma maculatum G4 S2 Tier 1 SS SS Townsend’s big-eared bat Corynorhinus townsendii G4 S2 Tier 1 SC SS SS Tri-colored bat Perimyotis subflavus G2G3 S2 Petitioned* Western small-footed myotis Myotis ciliolabrum G5 S4 Yuma myotis Myotis yumanensis G5 S3 *Petition for listing 6/14/2016 with a 90 day substantial finding on 12/21/17.

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LITERATURE CITED CPW (Colorado Parks and Wildlife). 2015. State wildlife action plan: A strategy for conserving wildlife in Colorado. Denver, CO, 865 pp. Hamm, P. S., N. A. Caimi, D. E. Northup, E. W. Valdez, D. C. Buecher, C. A. Dunlap, D. P. Labeda, S. Lueschow, and A. Porras-Alfaro. 2017. Western bats as a reservoir of novel Streptomyces species with antifungal activity. Applied & Environmental Microbiology 83:1-10. Master L. L., D. Faber-Langendoen, R. Bittman, G. A. Hammerson, B. Heidel, L. Ramsay, K. Snow, A. Teucher, and A. Tomaino. 2012. NatureServe conservation status assessments: factors for evaluating species and ecosystem risk. NatureServe, Arlington. Available: (http://www.natureserve.org/sites/default/files/publications/files/natureserveconservationstatusf actors_apr12_1.pdf ; accessed December 2016). Neubaum, D. N., K. W. Navo, and J. L. Siemers. 2017. Guidelines for Defining Biologically Important Bat Roosts: A Case Study from Colorado. Journal of Fish and Wildlife Management 8:272-282. O'Shea, T. J., and M. A. Bogan. 2003. Monitoring trends in bat populations of the United States and territories: Problems and prospects. US Geological Survey, Biological Resources Discipline, Information and Technology Report, USGS/BRD/ITR—2003-0003 (see Supplemental Material, Reference S6); also available at https://pubs.usgs.gov/itr/2003/0003/report.pdf (March 2018). USFWS (US Fish and Wildlife Service). 1994. 50 CFR Part 17. Endangered and threatened wildlife and plants: animal candidate review for listing as endangered or threatened species. Federal Register 59(219):58982–59028. Winter, A. S., J. J. M. Hathaway, J. C. Kimble, D. C. Buecher, E. W. Valdez, A. Porras-Alfaro, J. M. Young, K. J. H. Read, and D. E. Northup. 2017. Skin and fur bacterial diversity and community structure on American southwestern bats: effects of habitat, geography and bat traits. PeerJ, Vol 5 5:e3944.

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XII. ASSESSING THREATS TO BAT SPECIES: THE COLORADO BAT MATRIX

By Daniel J. Neubaum

While revising the Colorado Bat Conservation Plan, the Colorado Bat Working Group (CBWG) identified the need for a stand-alone, readily-accessible, reference document that identified and ranked potential threats (e.g., timber harvest, urbanization, energy development) facing Colorado bat species. Previous efforts to rank species status were problematic as many of the scores were vulnerable to personal bias and were changed when ranking outcomes resulted in values that bat experts did not feel were reflective of the threats facing a given species, or when the degree of the threat was compared between species. The Colorado Bat Matrix is the result of collaboration between CBWG members from universities, the private sector, and state and federal agencies, and is housed on the CBWG website for ease of access and revision (http://www.cnhp.colostate.edu/batmatrix/).

The primary audience for the Matrix is biologists and land managers who can use the rankings as a starting point for identifying threats to bat species. Researchers may also find the Matrix useful to identify gaps in knowledge for future study. We ranked the scope, severity, and immediacy of potential threats as high, moderate, low, or insignificant for 18 species of bats found in Colorado following methodology similar to NatureServe threat rankings (Masters et al. 2012). This ranking process avoids the pitfalls of personal bias and comparison of species, and, instead, focuses on the impacts of each threat to a given species with consideration given to the population.

CBWG DEFINITIONS

SCOPE The proportion of the bat’s population that is observed, inferred, or suspected to be directly or indirectly affected by the threat within Colorado. Because specific information on a species' statewide population is often lacking, the range of the species within Colorado is used.

Domain values for Scope of Threat are: High = > 60% of total population Moderate = 20-60% of total population Low = 5-20% of total population Insignificant = < 5% of total population

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SEVERITY

How badly and irreversibly the impacted population may be directly or indirectly affected by the threat within Colorado. Severity is evaluated at the level the threat (regional/local).

Domain values for Severity of Threat are: High = Loss of population (all individuals) or destruction of habitat in area affected, with effects essentially irreversible or requiring long-term recovery (>50 years) of the affected population. Moderate = Major reduction of population or long-term degradation or reduction of habitat in area affected, requiring 20-50 years for recovery Low = Low but nontrivial reduction of population or reversible degradation or reduction of habitat in area affected, with recovery expected in 5-20 years Insignificant = Essentially no reduction of population or degradation of habitat, due to threats, with ability to recover quickly (within 5 years) from minor temporary loss

IMMEDIACY Imminence of the threat to the species (i.e., how likely the threat is and how soon it is expected to be realized) within Colorado.

Domain values for Immediacy of Threat are: High = Threat is operational (happening now) or imminent (within a year) Moderate = Threat is likely to be operational within 2-5 years Low = Threat is likely to be operational within 5-20 years Insignificant = Threat not likely to be operational within 20 years

FINAL VALUE

These rankings were condensed into a value ranging from “A,” substantial, imminent threat, to “H,” unthreatened. To illustrate the Matrix results, rankings for the Townsend’s big-eared bat (Corynorhinus townsendii), a sensitive species for the USDA Forest Service and Bureau of Land Management in Colorado and a Tier 1 species of special concern as designated by Colorado Parks and Wildlife in the Colorado state wildlife action plan (2015), are shown in Figure 12.1. In Colorado, the greatest potential threats to this species are abandoned mine lands closure programs and renewed uranium mining with rankings of A (substantial, imminent threat) and B (moderate and imminent threat) respectively. Conversely, grazing and fuels treatments are unlikely to significantly affect Townsend’s big-eared bat populations and given a rank of H or unthreatened. Determination of domain values for bat populations

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can be difficult given the absence of good data for most bat species. Consequently, this tool has provided rankings for biologists and land managers made by local bat experts in lieu of better population data.

A = Substantial, imminent threat

B = Moderate and imminent threat

C = Substantial, non-imminent threat

D = Moderate, non-imminent threat

E = Localized substantial threat

F = Widespread, low-severity threat

G = Slightly threatened

H = Unthreatened

Figure 12.1. Threat potential for Townsend’s big-eared bat (Corynorhinus townsendii) as ranked by the Colorado Bat Matrix in 2009.

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The Colorado Bat Matrix serves as a model to rapidly identify threats to bat populations. This tool may assist biologists and land managers in determining which species or threats to focus limited resources. The Colorado Bat Matrix is a living document that will improve as gaps in bat populations and natural history are addressed. To access the Colorado Bat Matrix to explore threats to bat species of Colorado or to download a spreadsheet with full ranking descriptions/justifications along with associated literature, visit the CBWG website at http://www.cnhp.colostate.edu/batmatrix/methods.aspx.

LITERATURE CITED CPW (Colorado Parks and Wildlife). 2015. Colorado state wildlife action plan: A strategy for conserving wildlife in Colorado. Denver, CO, 865 p. Master, L. L., D. Faber-Langendoen, R. Bittman, G. A. Hammerson, B. Heidel, L. Ramsay, K. Snow, A. Teucher, and A. Tomaino. 2012. NatureServe Conservation Status Assessments: Factors for evaluating species and ecosystem risk. NatureServe, Arlington, Virginia; also available at (http://www.natureserve.org/sites/default/files/publications/files/natureserveconservationstatusf actors_apr12_1.pdf (June 2016).

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XIII. SPECIES ACCOUNTS

The majority of the following species accounts were originally written by various members of the Western Bat Working Group in preparation for the WBWG workshop in Reno, Nevada, February 9-18, 1998. They have been reviewed and updated by various members of the Colorado Bat Working Group for the 2018 revision of the Colorado Bat Conservation Plan. Several species accounts were newly developed for the second edition of the plan and authorship reflects this difference.

The status of Colorado bat species as ranked by NatureServe and the Colorado Natural Heritage Program (NatureServ/CNHP), The Colorado Parks and Wildlife State Wildlife Action Plan (SWAP) rankings and state threatened and endangered list, Colorado Bureau of Land Management (BLM), Region 2 of the US Forest Service (USFS), and the US Fish and Wildlife Service (USFWS) as of December 2017 is included in each species account. Conservation status of bat species, as defined by NatureServe, is ranked on a scale of 1–5 as follows: critically imperiled (G1), imperiled (G2), vulnerable (G3), apparently secure (G4), and demonstrably secure (G5). Assessment and documentation of status occurs at 3 geographic scales: global (G), national (N), and state/province (S). The CPW State Wildlife Action Plan ranks include Tier 1 for species of highest conservation priority and Tier 2 for species whose listing status is of concern but the urgency of action is deemed to be less. BLM and USFS rankings are given for sensitive species (SS) only as no threatened or endangered bat species currently exist in their management boundaries.

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ALLEN’S BIG-EARED BAT (IDIONYCTERIS PHYLLOTIS)

Prepared by Michael J. O’Farrell Updated by Daniel. J. Neubaum (2017)

DESCRIPTION

Allen’s big-eared bat (Idionycteris phyllotis) can be distinguished from all other bat species by the conspicuous presence of 2 facial lappets projecting over the forehead from the median bases of the ears. The ears are very large in proportion to the body and the calcar is keeled. This medium-sized bat is similar in appearance to Townsend’s big-eared bat (Corynorhinus townsendii), with a tan to olive brown dorsal pelage.

The measurements of this bat as recorded by Armstrong et Allen’s big-eared bat. Photo by D. Neubaum. al. (2011) are: total length 103–121 mm; tail 46–55 mm; hindfoot 9–12 mm; ear 38–43 mm; forearm 43–49 mm; wingspan 31–35 cm; weight 8–16 g.

DISTRIBUTION

One of the rarest bats in North America, Allen’s big-eared bat, a member of the family Vespertilionidae, has a relatively broad distribution from central Mexico through much of the southwestern US. Most records are known from Arizona, New Mexico, southern Nevada, and southern Utah. In Colorado, this species is considered an occasional visitor as no reproduction or permanent roosting has been confirmed. One mummified specimen of a nonreproductive adult female was collected from a picnic shelter at James M. Robb State Park near Fruita, Colorado in 2014 (Adams and Lambeth 2015). An acoustic call was also recorded for this species near La Sal Creek in extreme western Colorado near the state line with Utah (Hayes et al. 2009). Additional records for Allen’s big- Only one specimen of Allen’s big-eared bat has been collected in Colorado. eared bat have been collected in the La Sal Mountains, Utah, a short distance from the state line with Colorado (Wright 2012). Recorded locations range from Mojave Desert scrub to fir forest at elevations ranging from 855–3225 m, although most captures are from elevations between 1100–2500 m in oak-juniper woodland and ponderosa pine forest.

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NATURAL HISTORY

The preponderance of captures associated with scrub woodland and forest for this species are also associated with cliffs and rocky slopes, suggesting a roosting relationship with trees, caverns and rock fissures (Haymond et al. 2002; Siders and Jolley 2009; Solvesky and Chambers 2009). Maternity colonies have been found within passages of large boulder piles, cliffs, trees, and in abandoned mine tunnels. Work in northern Arizona revealed maternity colonies of this species using ponderosa pine snags that may turn over due to decay in as little as a decade or two (Rabe et al. 1998; Solvesky and Chambers 2009). Male bats have been found to form small bachelor colonies that roosted in sandstone cliffs (Solvesky and Chambers 2009). Pregnant individuals typically occur in June, with parturition in mid to late June, and lactation extending through early August. A single young is produced annually. Food appears to consist primarily of microlepidopterans (6–12 mm long), although other items are eaten, at least opportunistically. Winter status is not well understood. Individuals may move from higher elevation summer ranges to low elevation winter habitats. Allen’s big-eared bats produce audible echolocation calls, which can be used in detections for this species.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G4 S1 Tier2 - SS - - *See text on the first page of this section for an explanation of listing categories.

THREATS

An important threat to Allen’s big-eared bat may be the availability of maternity roosts. Specific physical requirements and the ephemeral nature of exfoliating bark on tree snag roosts appear to be highly limiting in some areas (Rabe et al. 1998; Solvesky and Chambers 2009). Maternity roosts in ponderosa snags have a relatively short lifespan of use in comparison to rock crevice roosts. Consequently, it is critical that proper forest management that provides for large diameter snag retention within ponderosa forest is prioritized to retain sufficient roosts for this species in those areas. Rock crevices used by this species, although documented, have not been characterized. Additionally, the rarity and patchy distribution of this species, as well as its apparent high degree of specialized feeding strategy, compounds its sensitivity to disturbance.

GAPS IN KNOWLEDGE

Very little is known of winter roosts used by this species. By deduction, it appears there are at least some elevational movements between summer and winter ranges. Very little is known concerning foraging behavior and requirements. Reproductive biology and population dynamics are poorly understood. It will be necessary to gather these data to properly evaluate potential threats and provide adequate management protocols. The current lack of knowledge suggests the need for the same intensity of focused surveys throughout the geographic range as has been accorded to the more widespread, and apparently more common, spotted bat (Euderma maculatum).

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LITERATURE CITED Adams, R. A., and R. Lambeth. 2015. First physical record of Allen's lappet-browed bat (Idionycteris phyllotis) in Colorado. Southwestern Naturalist 60:273-275. Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. Second edition. University Press of Colorado, Boulder, CO. Cockrum, E. L., B. Musgrove, and Y. Petryszyn. 1996. Bats of Mohave County, Arizona: populations and movements. Occasional Papers, The Museum, Texas Tech University 157:1-71. Czaplewski, N. J. 1983. Idionycteris phyllotis. Mammalian Species 208:1-4. Hayes, M. A., K. W. Navo, L. R. Bonewell, C. J. Mosch, and R. A. Adams. 2009. Allen’s big-eared bat (Idionycteris phyllotis) documented in Colorado based on recordings of its distinctive echolocation call. Southwestern Naturalist 54:499-501. Haymond, S., M. A. Bogan, E. W. Valdez, and T. J. O’Shea. 2002. Ecology and status of the big free-tailed bat (Nyctinomops macrotis) in southeastern Utah with comments on Allen's big-eared bat (Idionycteris phyllotis). Pages 22 pp in B. R. D. U.S. Geological Survey, Midcontinent Ecological Science Center, Department of Biology, University of New Mexico, editor. U.S. Geological Survey,Albuquerque, NM. Hoffmeister, D. F. 1986. Mammals of Arizona. University of Arizona, Tucson. 602 pp. Rabe, M. J., T. E. Morrell, H. Green, J. C. deVos, Jr., and C. R. Miller. 1998. Characteristics of ponderosa pine snag roosts used by reproductive bats in northern Arizona. Journal of Wildlife Management 62:612-621. Siders, M. S., and W. Jolley. 2009. Roost sites of Allen's lappet-browed bats (Idionycteris phyllotis). Southwestern Association of Naturalist 54:201-203. Solvesky, B. G., and C. L. Chambers. 2009. Roosts of Allen's lappet-browed bat in northern Arizona. The Journal of Wildlife Management 73:677-682. Tumlison, R. 1993. Geographic variation in the lappet-eared bat, Idionycteris phyllotis, with descriptions of subspecies. Journal of Mammalogy 74:412-421. Wright, A. L. 2012. Southeastern Utah forest and rangeland bat inventory 2012. Utah Division of Wildlife Resources, Price, UT

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BIG BROWN BAT (EPTESICUS FUSCUS)

Prepared by J. Mark Perkins Updated by Daniel J. Neubaum (2017)

DESCRIPTION

The big brown bat (Eptesicus fuscus) is a medium- to large- sized North American vespertilionid. It can be distinguished from all other large vespertilionids by the combination of size, a keeled calcar and a blunt tragus. Pelage color ranges from pale to dark brown and the tip of its tail usually extends 3 mm beyond the uropatagium. Two lineages have been described in Colorado with a split occurring for them geographically between the Front Range and the eastern plains of the state (Neubaum, M. et al. 2007). Big brown bat. Photo by D. Neubaum

Measurements for big brown bats in Colorado are: total length 90–138 mm; length of tail 34–56 mm; length of hindfoot 11–13 mm; length of ear 14–18 mm; length of forearm 39–54 mm; wingspan 32–40 cm; weight 12–20 g. See Armstrong et al. (2011) for more details, including dentition.

DISTRIBUTION:

The big brown bat has an extremely broad distribution, reaching from Alaska and northern Alberta to northern South America. In the US, it occurs in every state except Hawaii, ranging from coast to coast. Big brown bats occur across a wide variety of habitats in Colorado, ranging from low elevation desert scrub to high elevation conifer forests. This bat species, perhaps more than any other, has readily adapted to urbanized environments in Colorado (Everette et al. 2001; Neubaum et al. 2007; O’Shea et al. 2011).

NATURAL HISTORY

Big brown bats are a colonial species with the size of maternity colonies varying from about a dozen to several hundred (Everette et al. 2001; Neubaum et al. 2007; O’Shea et al. 2011). This species is well known for its propensity to roost in anthropogenic structures including buildings, and bridges, but has also been found in mines, caves, and large diameter tree snags across the western US. More recently, rock crevices in cliff faces were used as maternity roosts in the slickrock canyonlands of Colorado National Monument (Neubaum 2017). Surveys of abandoned mines in Colorado from 1990–2010 documented only 100 big brown bats roosting in mines, with 26 of those found during winter surveys. Similar results for caves suggest big brown bats aren’t as dependent on these types of features in the state as found in other parts of North America. Bridges and porches are commonly used as night roosts by males, and pre-parturition and post-lactating females. Big brown bats appear to be a relatively

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sedentary species and are not known to migrate large distances in western states. Migrations in elevation by males and females have been noted for this species in a number of studies across the western U.S. (Perkins 1996; Easterla 1973). In Colorado, females roosted separately from males in the spring and summer with a segregation of the sexes by elevation noted along the Front Range (Neubaum et al. 2006). During autumn, female bats migrated a short distance in elevation from maternity

Potential distribution of big brown bats in Colorado. colonies in buildings to rock crevices in the adjacent The map was generated using landscape-scale mountains where they joined males. Big brown bats coefficients and known locations in MaxEnt to model predictive probability of occurrence surfaces. hibernate for most of the winter in the northern portion of their range, but are active on warm nights in the winter in the southwest. In the West, this species is known to hibernate in relatively small numbers per site in caves, buildings and mines (Perkins 1996). Big brown bats tend to forage within a few kilometers of the roost, generally pursuing prey in tree canopies, over meadows, or along watercourses. Individuals tracked from capture sites to maternity roosts in Fort Collins averaged 1.9 km. Maximum distances moved away from maternity roosts to foraging areas in Fort Collins averaged 5.9 km with some ranging as far as 18 km within a night (O’Shea et al. 2011). However, big brown bats caught foraging at the Rocky Mountain Arsenal moved considerably farther, ranging 9.2–18.8 km (Everette et al. 2001). Diet analysis suggests that this species feeds primarily on heavy-bodied insects and is an important predator on certain agricultural pests (e.g., Diabrotica, the spotted cucumber beetle). Although primarily beetle (coleopteran) specialists, their diet also includes hemipterans, dipterans, lepidopterans, trichopterans, and hymenopterans. Valdez and O’Shea (2015) found big brown bats capitalizing on brief seasonal migrations of miller moths (Euxoa auxiliaris), accounting for 99% volume of fecal pellet analysis. This species is thought to mate in the autumn and winter, but ovulation does not occur until the spring. Each female produces 1 young (some individuals from the eastern plains of Colorado produce twins) in early summer, after a gestation of about 60 days (Neubaum, M. et al. 2007). The young are volant in 3–4 weeks.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G5 S5 - - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

Potential threats to this species include roost disturbance and destruction, particularly eviction of building-dwelling colonies by pest control operations, and removal of important roost trees during timber harvest. Grazing practices and loss of riparian areas could affect foraging habitat. Large-scale outbreaks of rabies may lead to large die-offs within maternity colonies of this species. Potential for population declines resulting from white-nose syndrome are possible as well.

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GAPS IN KNOWLEDGE

More information is needed on when and where mating occurs in western portions of the range of this species. Swarming locations are largely absent for big brown bats in western states. Movements during winter for this species in western states are largely unknown.

LITERATURE CITED Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. Second edition. University Press of Colorado, Boulder, CO. Betts, B. 1995. Roosting behavior of silver-haired and big brown bats in northeast Oregon. Pp. 55-61, in Bats and Forest Symposium, (R. M. R. Barclay and M. R. Brigham, eds.), October 19-21, 1995, Victoria, British Columbia. Research Branch, B. C. Ministry of Forests, Victoria. Working Paper 23/1996. Brigham, R. M. 1991. Flexibility in foraging and roosting behaviour by the big brown bat (Eptesicus fuscus). Canadian Journal of Zoology 69:117-121. Easterla, D. A. 1973. Ecology of the 18 species of chiroptera at Big Bend National Park, Texas. Northwest Missouri State University. Report Part 1 and 2. Everette, A. L., T. J. O'Shea, L. E. Ellison, L. A. Stone, and J. L. McCance. 2001. Bat use of a high plains urban wildlife refuge. Wildlife Society Bulletin 29:967-973. Kalcounis, M. 1994. Abstract. Selection of tree roost sites by big brown (Eptesicus fuscus), little brown (Myotis lucifugus) and hoary (Lasiurus cinereus) bats in Cypress Hills, Saskatchewan. Bat Research News 35:103. Kurta, A. and R. H. Baker. 1990. Eptesicus fuscus. Mammalian Species 356:1-10. Neubaum, D. J. 2017. Bat Composition and Roosting Habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 - 2016. Colorado Parks and Wildlife, Grand Junction, CO. Neubaum, D. J., T. J. O'Shea, and K. R. Wilson. 2006. Autumn migration and selection of rock crevices as hibernacula by big brown bats in Colorado. Journal of Mammalogy 87:470-479. Neubaum, D. J., K. R. Wilson, and T. J. O'Shea. 2007. Urban maternity-roost selection by big brown bats in Colorado. Journal of Wildlife Management 71:728-736. Neubaum, M. A., M. R. Douglas, M. E. Douglas, and T. J. O'Shea. 2007. Molecular ecology of the big brown bat (Eptesicus fuscus): Genetic and natural history variation in a hybrid zone. Journal of Mammalogy 88:1230-1238. O'Shea, T. J., D. J. Neubaum, M. A. Neubaum, P. M. Cryan, L. E. Ellison, T. R. Stanley, C. E. Rupprecht, W. J. Pape, and R. A. Bowen. 2011. Bat ecology and public health surveillance for rabies in an urbanizing region of Colorado. Urban Ecosystems 14:665-697. Perkins, J. M. 1996. Bat distribution within a managed forest. Pp. 164-174 in Bats and Forest Symposium, (R. M. R. Barclay and M. R. Brigham, eds.), October 19-21, 1995, Victoria, British Columbia. Research Branch, B. C. Ministry of Forests, Victoria. Working Paper 23/1996.

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Valdez, E. W., and T. J. O'Shea. 2015. Seasonal shifts in the diet of the big brown bat ( Eptesicus fuscus), Fort Collins, Colorado. Southwestern Naturalist 59:509-514. Vonhof, M. 1995. Roosting ecology and roost-site preferences of reproductive Eptesicus fuscus and Lasionycteris noctivagans in the Pend D’Oreille Valley in southern British Columbia. Pp. 62-80, in Bats and Forest Symposium, (R. M. R. Barclay and M. R. Brigham, eds.), October 19-21, 1995, Victoria, British Columbia. Research Branch, B. C. Ministry of Forests, Victoria. Working Paper 23/1996. Whitaker, J. O., Jr. 1995. Food of the big brown bat Eptesicus fuscus from maternity colonies in Indiana and Illinois. American Midland Naturalist 134:346-360.

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BIG FREE-TAILED BAT (NYCTINOMOPS MACROTIS)

Prepared by Kirk W. Navo Updated by Kirk W. Navo and Daniel J. Neubaum (2017)

DESCRIPTION

The big free-tailed bat (Nyctinomops macrotis), a member of the family Molossidae, can be distinguished from other molossids based on size. With an adult forearm of 58–64 mm it is larger than Brazilian free-tailed bats (Tadarida brasiliensis) or the pocketed free-tailed bat (N. femorosaccus), and smaller than either of the mastiff bats (Eumops spp.). It also has vertical grooves or wrinkles on the upper lip that are lacking in mastiff bats (Eumops spp.).

Big-free-tailed bat. Photo by D. Neubaum The measurements of the big free-tailed bat as recorded by Armstrong et al. (2011) and Neubaum (2017) are: total length of 125–140 mm; length of tail 48–54 mm; length of ear 9–11 mm; forearm length of 58–64 mm; wingspan of 42–46 cm; weight of 12–25 g.

DISTRIBUTION

The big free-tailed bat ranges from most of South America northward to include Mexico, Arizona, New Mexico, southern and western Texas, southern California, southeastern Nevada, southern Utah, and north to central Colorado. The species is migratory and there are some extralimital records from British Columbia, Iowa, Kansas, and South Carolina. The known elevation range is from near sea level to about 2600 m. In Colorado, this species was previously considered to be accidental in the state. The big free- tailed bat is now considered to be a summer resident in Colorado, with capture records for reproductive females and juveniles that have been collected from the desert canyon country of the Western Slope and river canyons in the southeastern portion of the state (Navo and Gore 2001; Neubaum 2017). Extralimital records of nonreproductive individuals considered to potentially be wanderers have been collected from the Front Range and plains in the eastern portion of the state (Armstrong et al. 2011).

NATURAL HISTORY

The big free-tailed bat appears to mainly inhabit rugged, rocky habitats in arid landscapes. It has been found in a variety of plant associations including desert shrub, woodlands, and evergreen forests. It appears to be associated with lowlands, but has been documented at around 2400 m in New Mexico. This species is a seasonal migrant and a powerful flyer, known to cover large circuits in a single night (Corbett et al. 2008). It roosts predominantly in the crevices of cliff faces, although there is some documentation of roosting in buildings, caves, and tree cavities. The species forms maternity colonies and females bear one young in late spring or early summer. Lactating females have been taken in July,

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August and September, and volant juveniles recorded as early as July and as late as November. Maternity roosts have been documented in rock crevices, with evidence of both long- and short-term use of the crevices reported (Haymond et al. 2002). Maternity colonies range widely in size with numbers as high as 800 individuals reported (Haymond et al. 2002). In western Colorado, maternity colonies in rock crevices of cliff faces numbered as high as 64 individuals (Neubaum 2017). Bats at one of these roosts were noted

Potential distribution of big free-tailed bats in using long, straight dives parallel to the cliff face that Colorado. The map was generated using landscape- allowed great speed to be attained quickly upon exit. Such scale coefficients and known locations in MaxEnt to model predictive probability of occurrence surfaces. displays were also noted at a large colony in southeast Utah, potentially as a predator avoidance tactic (Haymond et al. 2002). Upon return to the roost site this bat may utilize ritualized behavior that includes a general reconnaissance of the site and several landing trials before entry. Big free-tailed bats forage almost entirely on large moths, but some data exists to document occasional foraging on other insects including grasshoppers, beetles, crickets, leafhoppers and flying ants. Raptors, including peregrine falcons and owls, are documented predators of this species. Big free-tailed bats have an audible echolocation call that is characterized as loud and with a frequency range of 17–30 kHz. Surveys based on echolocation calls for detecting this species may be necessary since captures appear to be uncommon. Acoustic calls of this species have been documented in Dinosaur National Monument and south to Mesa Verde National Park. Easterla (1973) reported that populations of this bat from Big Bend National Park fluctuated greatly from year-to-year. Haymond et al. (2002) provide evidence that alternate roosts are used by this species, even in cases of large maternity colonies, as reflected by large fluctuations in colony size from day to day. Similar trends have been noted for some roosts in Colorado (Neubaum 2017). Little is known about the species population dynamics and ecology.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G5 S1 Tier 2 - SS - - *See text on the first page of this section for an explanation of listing categories.

THREATS

The Colorado Bat Matrix (See chapter XII. Assessing threats to bat species: the Colorado Bat Matrix; http://cnhp.colostate.edu/batmatrix/) does not identify any notable threats to the species. However, large water impoundments were mentioned as having the potential to inundate large numbers of rock crevices along high cliffs where such features are constructed (e.g., Lake Powell in southern Utah). Displacement of many roosts during a small window of time, as would be expected from such an activity, may have the potential to impact local populations of the species. Recreational climbing of the high cliffs used by this bat also has potential to disturb maternity colonies for this species but these

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interactions have not been studied. General threats that apply to other bat species, such as disturbance to foraging areas from grazing, riparian and water flow management, and use of pesticides have potential to affect this species.

GAPS IN KNOWLEDGE

Information is needed on big free-tailed bats regarding roosting ecology, seasonal movement patterns, and breeding colony distribution. Current evidence suggests that the species breeds farther north than previously thought, including southern Utah and west central Colorado. Reference calls are needed to improve call libraries used to train acoustic software packages, which may be needed to adequately detect the species during these types of surveys.

LITERATURE CITED Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. Second edition. University Press of Colorado, Boulder, CO. Corbett, R. J. M., C. L. Chambers, and M. J. Herder. 2008. Roosts and activity areas of Nyctinomops macrotis in northern Arizona. Acta Chiropterologica 10:323-329. Di Salvo, A. F., H. N. Newhauser, and R. E. Mancke. 1992. Nyctinomops macrotis in South Carolina. Bat Research News 33(2&3):21-22. Easterla, D. 1973. Ecology of the 18 species of Chiroptera at Big Bend National Park, Texas. Northwest Missouri State University Studies 34:1-165. Haymond, S., M. A. Bogan, E. W. Valdez, and T. J. O’Shea. 2002. Ecology and status of the big free-tailed bat (Nyctinomops macrotis) in southeastern Utah with comments on Allen's big-eared bat (Idionycteris phyllotis). Pages 22 pp in B. R. D. U.S. Geological Survey, Midcontinent Ecological Science Center, Department of Biology, University of New Mexico, editor. U.S. Geological Survey, Albuquerque, NM. Milner, J., C. Jones, and J. K. Jones, Jr. 1990. Nyctinomops macrotis. Mammalian Species 355:1-4. Nagorsen, D. W., and R. M. Brigham. 1993. Bats of British Columbia. University of British Columbia Press, Vancouver. 164 pp. Navo, K. W., and J. A. Gore. 2001. Distribution of the big free-tailed bat (Nyctinomops macrotis) in Colorado. The Southwestern Naturalist 46:370-376. Neubaum, D. J. 2017. Bat composition and roosting habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 to 2016. Colorado Parks and Wildlife, Grand Junction, CO. Schmidly, D. J. 1991. The Bats of Texas. University of Texas Press, Austin. 189 pp.

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BRAZILIAN FREE-TAILED BAT (TADARIDA BRASILIENSIS )

Prepared by Bat Conservation International Updated by Kirk W. Navo (2017)

DESCRIPTION

The Brazilian free-tailed bat (Tadarida brasiliensis) is a member of the Family Molossidae, and like other molossid (free-tail) species, has a tail that extends well beyond the back edge of the interfemoral membrane. T. brasiliensis can be distinguished from the other molossids occurring in the U.S. by its ears, which are not joined basally at the mid-line.

The measurements of the Brazilian free-tailed bat as recorded by Armstrong et al. (2011) are: total length of 90–105 mm; Brazilian free-tailed bat. Photo by D. length of tail 32–40 mm; length of ear 11–14 mm; forearm Neubaum length of 36–46 mm; wingspan of 30–35 cm; weight of 8–12 g.

DISTRIBUTION

The Brazilian free-tailed bat is one of the most widely distributed mammalian species in the Western Hemisphere. There are 9 recognized subspecies, with 2 occurring in the U.S. T. b. mexicana is primarily western, occurring from southern Oregon to eastern Nebraska and south through Mexico. T. b. cynocephala is primarily a southeastern species, from eastern Kentucky into South Carolina and south through Florida. T. brasiliensis ranges southward through most of Central America. In the western U.S., T. brasiliensis is most commonly associated with dry, lower elevation habitats, yet it also occurs in a variety of other habitats and is found up to 3000 m in some of the western mountain ranges.

In Colorado, more recent documentations of this species across the western and central parts of the state have been recorded. Specimens have been recorded from Dinosaur National Monument, south to Mesa Verde National Park. Over the last 20 years, several observations of large numbers of Tadarida occupying buildings during the fall migration season have been reported. These have been Potential distribution of Brazilian free-tailed bats in Colorado. The map was generated using landscape- reported in western Colorado cities such as Glenwood scale coefficients and known locations in MaxEnt to Springs and Delta. Additionally, several documentations of model predictive probability of occurrence surfaces. maternity roosts have been reported and confirmed in Grand Junction, and Colorado National Monument (Neubaum 2017). In 2015, a large maternity roost was discovered in a bridge east of Grand Junction. The species is well established in south-central

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Colorado, and has also been documented in southeast Colorado. Acoustic calls auto-classified as T. brasiliensis have been recorded in many parts of Colorado, including the northern Front Range. Because acoustic calls of this species are variable and can be confused with several other species, additional documentation of specimens will be necessary to confirm actual distribution in the state. The known distribution of this species has changed significantly since the early 1980’s, when the southern half of the state was considered the northern extent of Brazilian free-tailed bats in Colorado.

NATURAL HISTORY

This species is highly colonial with maternity colonies ranging in size from a few hundred to 20 million. The most commonly used natural roosts are caves and rock crevices on cliff faces. This species also roosts in abandoned mines and tunnels, highway bridges and large culverts, buildings, and bat houses. Maternity roosts are usually warmer and larger than bachelor or non-reproductive female roosts. In Colorado, a large bachelor colony first documented in 1971, is established in the Orient Mine; an abandoned iron-ore mine located in the north end of the San Luis Valley, on property belonging to the Orient Land Trust. This is one of the largest, northern most known roost sites of this species in the West. It is estimated between 100,000 to 250,000 in size, and is the largest known bat roost in Colorado. Bats start to arrive at the roost in late May, and build in numbers to a peak in mid-summer, before beginning their southern migration in late August through mid-October. Females and young of the year begin to show up at the roost site by mid-August, providing further evidence that the species is breeding in the state, and a summer resident in areas of northern Colorado. T. brasiliensis will take refuge in cliff swallow nests during spring cold snaps. Brazilian free-tailed bats often fly more than 50 km to reach foraging areas, and in the San Luis Valley, the species has been documented foraging over 60 km from the Orient Mine. Such flight is rapid, direct, and often involves gliding. Bats from one colony may cover areas as large as 400 km2 and move at speeds over 40 km/hour and at altitudes of 3000 m or more. Foraging occurs at high elevations and also at heights of 6–15 m. This species consumes a large variety of agricultural pests, mostly moths, but also flying ants, weevils, stinkbugs, and ground beetles, and the agricultural economy of the San Luis Valley is likely benefiting for the colony at the Orient Mine. The Brazilian free-tailed bat (T. b. mexicana) is primarily migratory, with large numbers of females returning to large, warm caves in Texas, New Mexico, Arizona, and Oklahoma each spring. Mating probably occurs in lower latitudes of the winter range. Seasonal patterns elsewhere in the west are less clear. Birth usually occurs between mid-June and mid-July. Adult mass is reached in as little as 3 weeks and first flight occurs 2–3 weeks later.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G5 S1 - - - - - *See text on the first page of this section for an explanation of listing categories.

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THREATS

Besides human disturbance and habitat destruction (e.g., alteration of suitable caves, mines, bridges, and old buildings) noted above, there are problems with pesticide poisoning and deliberate eradication attempts. Human rabies deaths attributed to Brazilian free-tailed bats foster attitudes for the destruction of their roosts and colonies. The Brazilian free-tailed bat is a non-hibernating species, so the risk from WNS is not considered significant. However, it is unknown if the species could play a role in the spread of the disease to western states. Continued support for long term conservation of the bachelor colony at the Orient Mine and the Orient Land Trust is necessary to maintain the status of the species in Colorado.

GAPS IN KNOWLEDGE

Although most major maternity roosts in the U.S. are now protected, much remains to be done with winter roosts in Mexico. More documentation of the role of the Brazilian free-tailed bat in agriculture, and the use of artificial roosts to attract them, is needed. This would be particularly important in the San Luis and Grand Valley’s of Colorado. Its ecology, distribution, and seasonal patterns are not well understood in some parts of its range, particularly California, Nevada, southern Oregon, and Utah. Additional acoustic data and specimen verifications are needed in many parts of Colorado.

LITERATURE CITED Armstrong, D. M. J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado, 2nd edition. Denver Museum of Nature and Science. University Press of Colorado, 11:327-328. Freeman, G. E., and L. Wunder. 1988. Observations at a colony of the Brazilian free-tailed bat (Tadarida brasiliensis) in southern Colorado. Southwestern Nat., 33:102-103. Loughry, W. J., and G. F. McCracken. 1991. Factors influencing female-pup scent recognition in Mexican free-tailed bats. Journal of Mammalogy 72:624-626. McCracken, G. F. 1996. Bats aloft: a study of high-altitude feeding. Bats 14:7-10. McCracken, G. F., and M. K. Gustin. 1991. Nursing behavior in Mexican free-tailed bat maternity colonies. Ethology 89:305-321. McCracken, G. F., M. K. Gustin, and A. T. Vawter. 1994. Genetic structure in migratory populations of the bat Tadarida brasiliensis mexicana. Journal of Mammalogy 75:500-514. Meacham, J. W. 1974. A Colorado colony of Tadarida brasiliensis. Bat Res. News, 15:8-9. Neubaum, D. J. 2017. Bat composition and roosting habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 to 2016. Colorado Parks and Wildlife, Grand Junction, CO. Schmidley, D. J. 1991. The Bats of Texas. Texas A&M University Press, College Station. 188 pp. Svoboda, P. L., and J. R. Choate. 1987. Natural history of the Brazilian free-tailed bat in the San Luis Valley of Colorado. J. Mamm., 68:224-234. Wilkins, K. T. 1989. Tadarida brasiliensis. Mammalian Species 331:1-10.

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CALIFORNIA MYOTIS (MYOTIS CALIFORNICUS)

Prepared by Michael A. Bogan, Ernest W. Valdez, and Kirk W. Navo Updated by Milu Velardi (2017)

DESCRIPTION

The California myotis (Myotis californicus) is a small bat with dark wings and dull yellowish brown pelage, although individuals can range in color from pale tan to dark brown. The hairs on the body lack burnished tips, with those on the ventral side of the patagium not extending to the elbow. It has a distinctly keeled calcar and dark brown to black ears. This species closely resembles the Western small-footed bat (M. ciliolabrum) and warrants close inspection to distinguish them. The ears of the California myotis are long and extend California myotis. Photo by D. Neubaum beyond the nose when laid forward. A second feature to differentiate the two in hand is tail length: the tail of the western small-footed bat may project 1.5–2.5 mm beyond the uropatagium, while the tail of the California myotis will not (Constantine 1998). However this trait is not consistent in specimens examined in Colorado. The shape of the rostrum may be used to distinguish these two species as well, with the California myotis exhibiting more of a narrow U shape versus

Myotis ciliolabrum vs. M. californicus the broadened V shape of the Western small-footed bat. The facial appearance of this bat generally does not have as distinguished of a dark mask as its close counterpart as well.

The measurements of the California myotis as taken from Armstrong et al. (2011) are: total length 70–84 mm; tail 30–40 mm; hindfoot 5.5–8.2 mm; ear 11–15 mm, forearm 29–36 mm; wingspan 22–26 cm; weight 3–5 g.

Comparison of morphological measurements for Myotis californicus vs. Myotis ciliolabrum: Total length Tail Hindfoot Ear Forearm Wingspan Weight Species (mm) (mm) (mm) (mm) (mm) (cm) (g) M. californicus 70–84 30–40 5.5–8.2 11–15 29–36 22–26 3–5 M. ciliolabrum 75–88 33–42 5–8 12–16 30–35 21–25 3.5–5.5 DISTRIBUTION

Distribution of the California myotis in the U.S. includes mesa country and dry canyons of the west. It ranges from southeast Alaska and southwestern British Columbia, through most of the western U.S.,

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including the Rocky Mountains and south to Guatemala. In Colorado, it is common in semidesert shrublands and pinyon-juniper woodlands in the western portion of the state, up to elevations of approximately 2400 m. The California myotis has been captured in all of the counties along the western border of Colorado except Dolores County, but it is presumed to occupy that area as well. One subspecies, M. californicus stephensi, occurs in Colorado.

NATURAL HISTORY

The California myotis remains a bit of a mystery biologically. It is known that this elusive bat uses abandoned structures, caves, mines, and rock crevices in cliffs for roosting at night. Day roosts are similar, but can also be found in hollow trees and under loose bark as well. Surveys at abandoned mines from 1990-2010 in Colorado documented 298 California myotis. Most records are from summer/fall surveys, but several winter records have been documented in mines. This bat tends to be associated with low elevation zones that are warmer and more arid in Colorado (Neubaum Potential distribution California myotis in Colorado. 2017). Along the western slope, California myotis have been The map was generated using landscape-scale coefficients and known locations in MaxEnt to model observed using rocks as roosts, including in boulders, under predictive probability of occurrence surfaces. slabs, and in fissures and cracks of cliffs (BLM 2008).

The California myotis is an acrobatic flyer and uses small watering holes for drinking; the kidneys are adapted for arid environments. It forages early in the evening and flies 2–3 m above the ground, where they prey on moths, small beetles, and lacewings (Freeman 1984). Foraging has been documented over riparian canyons, arroyos, open areas, along cliff faces, and over stock tanks (Freeman 1984). California myotis mates during autumn, with young born in May and June in Colorado. Pregnant females have been captured in June and July in Colorado, along with lactating females captured in August (Adams 1988). Females form small maternity colonies and give birth to 1 pup each season. The winter range of the California myotis is still somewhat unclear. Hibernation records have been documented in mines, caves, and buildings in many western states (Simpson 1993). They have been observed as active for short periods in winter, which indicates an occasional emergence from torpor for feeding purposes, even in temperatures below freezing.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G5 S3 - - - - - *See text on the first page of this section for an explanation of listing categories.

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THREATS

The overall status of the California myotis is thought to be secure as of November 2016 (IUCN 2017). However, the species may be affected by closure of abandoned mines without adequate surveys and by recreational caving. The removal of large-diameter snags and treatment of pinyon-juniper stands in timber practices may also influence day roosting habitat. Some riparian-management practices and large scale water impoundment may be detrimental to local populations. Given its close relatedness to other Myotis affected by white-nose syndrome, the California myotis may prove to be highly vulnerable to effects from the disease if it progresses into Colorado.

GAPS IN KNOWLEDGE

More information and research is needed in Colorado regarding this species and the potential impacts from forestry management practices, such as pinyon-juniper treatments, and mine closures. General surveys of occurrence along riparian and cliff band stretches of the state’s western slope would be beneficial. North American Bat grids run in this portion of the state could also be reviewed for such presence/absence data. Determining winter roosts of this species is also needed.

LITERATURE CITED Adams, R. A. 1988. Trends in reproductive biology of some bats in Colorado. Bat Research News 29:21- 25. Armstrong, D. M. 1972. Distribution of mammals in Colorado. Monogr., Univ. Kansas Mus. of Nat. History, 3:1-415. Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado, 2nd edition. Denver Mus. of Nature and Science. University Press of Colorado, 11:327-328. BLM (Bureau of Land Management). 2008. Final Report: Book Cliff Survey for BLM Sensitive Bats. Interagency Agreement No. BLM-IA #06-IA-11221602-150. Constantine, D. G. 1998. An overlooked external character to differentiate Myotis californicus and Myotis ciliolabrum (Vespertilionidae). Journal of Mammology 79:624-630. Freeman, G. E. 1984. Ecomorphological analysis of an assemblage of bats: resource partitioning and competition. Unpubl. Doctoral dissert., Univ. Colorado, Boulder, 131 pp. IUCN (The IUCN Red List of Threatened Species). Version 2017-2. . Downloaded on 16 November 2017. Knopf, F. L. 1986. Changing landscapes and the cosmopolitism of the eastern Colorado avifauna. Wildlife Society Bulletin. 14:132-142. Neubaum, D. J. 2017. Bat Composition and Roosting Habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 to 2016. Colorado Parks and Wildlife, Grand Junction, CO. Simpson, M. R. 1993. Myotis californicus. Mammalian Species 428:1-4.

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CANYON BAT (PARASTRELLUS HERPERUS)

Prepared by Pat E. Brown Revised by Daniel J. Neubaum, and W. T. Turner (2017)

DESCRIPTION

Formerly known as the western pipistrelle (Pipistrellus hesperus), the canyon bat (Parastrellus hesperus) underwent a taxonomic revision and was reclassified by Hoofer et al. (2006) based on new morphological and genetic data and is now a member of the family Vespertilionidae. This species is one of the smallest bats in North America, weighing as little as 3 g with a wingspan of only 20 cm. P. hesperus is most often confused with the other small Myotis species (M. californicus or ciliolabrum) due to similarities in size, pelage Canyon bat. Photo by D. Neubaum color, and that all 3 bats have a keeled calcar. The canyon bat can easily be distinguished from these two Myotis by the obvious club-shaped tragus compared to the pointed tragus exhibited by the later two. In the southeastern canyons of Colorado there is the possibility for a slight overlap in range with the eastern tri-colored bat (Perimyotis subflavus), which is larger, with an unkeeled calcar, and tri- colored fur. P. hesperus is sexually dimorphic with females typically being larger than males.

The measurements of the canyon bat as recorded by Armstrong et al. (2011) are: total length of 60–86 mm; length of tail 25–36 mm; length of ear 12–14 mm; forearm length of 27–33 mm; wingspan of 19–23 cm; weight of 4–6 g.

DISTRIBUTION

The canyon bat is a non-migratory, resident of the desert lowlands of the southwestern U.S., north into southern Washington and east to western Colorado. In Mexico the species ranges south throughout Baja California and on the mainland to Michoacan and Hildago. In Colorado, most records of occurrence come from lower elevations of the canyonlands along the Western Slope (Armstrong et al. 2011). Additional records from the rivers and canyons of southeast Colorado have been collected.

NATURAL HISTORY

While most commonly associated with arid desert landscapes, the canyon bat also occurs around canyonlands in pinyon-juniper woodlands, and lower elevation mixed conifer and spruce-fir forest (Hoffmeister 1986). The common name “canyon” bat was derived from their strong association with rocky canyons and outcrops (usually at elevations below 2000 m), where they roost in small crevices (Cross 1965). Occupied crevices may also be used in abandoned mines and caves or on buildings (Barbour and Davis 1969). These bats have also been observed at dusk flying over creosote bush scrub

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several miles from rocky areas where they have been found roosting under rocks (Von Bloaker 1932). In Colorado, roosts located in Colorado National Monument were in rock crevices of small cliff bands or large free standing boulders located on the scree slopes below cliffs (Neubaum 2017). During cooler winter months, canyon bats are believed to hibernate in rock crevices, and to a lesser extent caves and mines, and on warm winter nights may emerge to drink or forage if insects are available (Ruffner et al. 1979). Miller

Potential distribution of canyon bats in Colorado. The (1964) noted activity for this species in western Colorado map was generated using landscape-scale coefficients every month of the year except December, January, and and known locations in MaxEnt to model predictive probability of occurrence surfaces. February. Mothers with their young may roost alone or in small maternal colonies (Adams 2003). Water availability is thought to be an important resource that influences the distribution of the species and where they roost. However, canyon bats do have the ability to concentrate urine more than other bat species, which has helped them adapt to arid desert environments (Geluso 1978). Known for being one of the most diurnal bat species in North America, P. hesperus generally are the first bat species to emerge early in the evening, even before sunset, and may be active after sunrise (Adams 2003). In addition, canyon bats are often the first bats captured in an evening in mist nets set over isolated desert water holes or across mine entrances (Cockrum and Cross 1965).

Because these bats are small and slow flyers they are often limited to small foraging circuits. The canyon bat feeds on a variety of insects, with stomach content analysis suggesting they feed on small swarming insects such as flying ants, mosquitoes, fruit flies, leafhoppers, and ants (Hayward and Cross 1979). Females give birth to twins in late May through July with newborn pups weighing less than 1 g (Adams 2003).

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G5 S4 - - - - - *See text on the first page of this section for an explanation of listing categories.

THREAT

Destruction of rocky areas due to renewed mining or other development activities (e.g., road construction, housing developments, and water impoundments) have potential to disturb or eliminate roosting habitat. Given that this bats eastern counterpart, the tri-colored bat, has been impacted by white-nose syndrome across its range, it is reasonable to assume that the canyon bat will be vulnerable to the disease as well if it reaches Colorado. However, the relatively solitary roosting habits of this species may limit the bat-to-bat transfer of the disease if it does reach the state. Currently there have

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been no reported cases of P. hesperus deaths as a result of white-nose syndrome at the time of writing for this plan.

GAPS IN KNOWLEDGE

Although the canyon bat is thought to be ubiquitous throughout the arid southwest, limited information is available on social structure, microhabitat roost requirements, roost fidelity, and longevity. In Colorado, data is largely absent on individual foraging areas and seasonal roost use.

LITERATURE CITED Adams, R. A. 2003. Bats of the Rocky Mountain West: Natural history, ecology, and conservation. University Press of Colorado. Boulder, CO. 289 pp. Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. Second edition. University Press of Colorado, Boulder, CO. Barbour, R. W., and W. H. Davis. 1969. Bats of America. University of Kentucky Press, Lexington. 286 pp. Bradley, W. G., and M. J. O'Farrell. 1969. Temperature relationships of the western pipistrelle (Pipistrellus hesperus). Pp. 85-96, in Physiological Systems in Semiarid Environments (C. C. Hoff and M. L. Riedesel, eds.). University of New Mexico Press, Albuquerque. Cockrum, E. L. and S. P. Cross. 1964. Time of bat activity over water holes. Journal of Mammalogy, 45: 635-636. Cross, S. P. 1965. Roosting habits of Pipistrellus hesperus. Journal of Mammalogy 46:270-279. Geluso, K. N. 1978. Urine concentrating ability and renal structure of insectivorous bats. Journal of Mammalogy 59:312-323. Hayward, B. J., and S. P. Cross. 1979. The natural history of Pipistrellus hesperus (Chiroptera: Vespertilionidae). Western New Mexico University, Office of Research 3:1-36. Hoffmeister, D. F. 1986. The Mammals of Arizona. University of Arizona Press, Tucson. 602 pp. Miller, P. H. 1964. The ecological distribution of mammals in Colorado National Monument, Mesa County, Colorado. Oklahoma State University, Stillwater, OK. Neubaum, D. J. 2017. Bat composition and roosting habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 - 2016. Colorado Parks and Wildlife, Grand Junction, CO. Ruffner, G. A., R. M. Poche, M. Meierkord, and J. A. Neal. 1979. Winter bat activity over a desert wash in southwestern Utah. Southwestern Naturalist 24:447-453. Schmidly, D. J. 1991. The Bats of Texas. Texas A&M University Press, College Station. 188 pp. Von Bloeker, J. C. 1932. The Roosting-Place of Pipistrellus Hesperus. Journal of Mammalogy 13:273.

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EASTERN RED BAT (LASIURUS BOREALIS)

Prepared by Milu Velardi and Daniel J. Neubaum (2017)

DESCRIPTION

The eastern red bat (Lasiurus borealis) is a common bat of the eastern U.S. and Canada and is easily recognized by its color. It is a medium-sized and reddish to yellow-red bat, with white-tipped dorsal hairs. Male eastern red bats are generally brighter in color than females. A pale buffy spot may be present on the shoulders, and often the ventral surface is paler than the dorsum. Wings are narrow. Like other members of the genus Lasiurus, the interfemoral membrane of the wings are densely furred above and sparsely furred below. Ears are short and rounded. The extension of the tail Eastern red bat. Photo by P. Cryan in flight distinguishes this species from others in its range.

The measurements of the eastern red bat as recorded by Armstrong et al. (2011) are: total length 107– 128 mm; tail 40–60 mm; hindfoot 11 mm; ear 8–13 mm, forearm 35–46 mm; wingspan 28–33 cm; weight 7–16 g.

DISTRIBUTION

Distribution of the eastern red bat in the U.S. includes the entire eastern half of the country and the eastern-most portions of Wyoming, Colorado, and New Mexico (Armstrong et al. 2011). It is found in the southeastern region of Canada and as far west as Alberta. Although the eastern red bat is abundant in the Midwestern U.S., there were only a handful of individuals observed in Colorado prior to the 1980’s. At that time, known counties included Weld, Arapahoe, Yuma, Otero, and Baca counties (Armstrong 1972). Since then, several new accounts have been made including acoustic recordings at Rocky Mountain Arsenal in 2001 (Everette et al. 2001), 2 individuals netted in Fort Collins on Spring Creek and near the Poudre River in 2005 (Neubaum 2005), a single bat found dead on the grounds of the Denver Zoo in 2006, and another netted in Bear Creek Canyon near Boulder in 2007. Recent records have been collected from east of Denver on the Lowry Bombing Range in 2013, the South Platte River near Chatfield Reservoir in

2013, Greenhorn Creek near Colorado City in 2015, and Potential distribution of eastern red bats in Colorado. The map was generated using landscape-scale along Walnut Creek in Jefferson County in 2016 (CPW coefficients and known locations in MaxEnt to model predictive probability of occurrence surfaces. Scientific Collections and Bat Database, searched September

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2017). An additional 13 red bats were salvaged during surveys related to wind farms in Logan County from 2012–2013 (Walsh 2013). Due to the increase in woody vegetation along riparian stretches and irrigation canals on the eastern plains as compared to a century ago, the availability in habitat for this species has become more extensive in eastern parts of Colorado. The advancement of irrigation related to canals and permanent flows on major rivers is attributed for this change in vegetation (Knopf 1986; Neubaum 2005). There is a single subspecies in Colorado: L. b. borealis. It is possible that a second subspecies, the western red bat (L. blossevillii), which occurs in the desert southwest, including the Grand Canyon and Utah, will eventually be found in southwestern Colorado (Baker et al. 1988).

NATURAL HISTORY

The eastern red bat is a solitary bat, roosting in trees and shrubs. When suspended from branches, these bats can appear to look like dead leaves. Red bats seem to favor trees located on the edge of clearings, fields and streams, roosting on the south and east sides of these trees. The bat’s roost area is often protected from all sides except below, where there is a clear flight path. The eastern red bat feeds early in the evening, with the majority of foraging occurring within the first few hours of darkness (Mumford 1973). Red bats are believed to be somewhat sedentary, remaining in the same areas to feed several nights in a row and remaining close to day roost locations. Mating for the eastern red bat occurs in August and September throughout most of their range. Females have the ability to store sperm until February or March. Copulation Red bat roosting in foliage of tree. occurs in flight with a gestation period of 80–90 days. Two to Photo by M. Smith. five young are born in May to early July (Hamilton et al. 1972), which is unusual for bats, which commonly give birth to a single pup. Young learn to fly at 4–5 weeks. Eastern red bats are believed to undertake long-distance migrations, arriving in the northern latitudes in May and early June and moving south again in September and October (LaVal et al. 1979). It is possible that individuals in Colorado move east and south in the autumn but information is still needed to verify these movements.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G3G4 S2S3B - - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

The overall status of the eastern red bat is thought to be secure as of November 2016. However, potential treats to this species from wind energy development have been identified in eastern parts of its range.

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GAPS IN KNOWLEDGE

More information and research is needed in Colorado regarding this species and the potential impacts on it from wind energy development. General surveys of occurrence along riparian stretches of the states eastern plains and foothills would be beneficial. North American Bat grids run in this portion of the state could also be reviewed for such presence/absence data.

LITERATURE CITED Armstrong, D. M. 1972. Distribution of mammals in Colorado. Monograph of the University of Kansas Museum of Natural History, 3:1-415. Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado, 2nd edition. Denver Museum of Nature and Science. University Press of Colorado, 11:327-328. Baker, R. J., J. C. Patton, H. H. Genoways, and J. W. Bickham. 1988. Genic studies of Lasiurus (Chiroptera: Vespertilionidae). Occasional Papers of the Museum. Texas Tech University, 117:1-15. Everette, A. L., T. J. O’Shea, L. E. Ellison, L. A. Stone, and J. L. McCance. 2001. Bat use of a high-plains urban wildlife refuge. Wildlife Society Bulletin. 29: 967-973. Hamilton, R. B. and D. T. Stalling. 1972. Lasiurus borealis with five young, Journal of Mammalogy. 53:10:125-134. Knopf, F. L. 1986. Changing landscapes and the cosmopolitism of the eastern Colorado avifauna. Wildlife Society Bulletin. 14:132-142. LaVal, R. K. and M. L. LaVal. 1979. Notes on reproduction, behavior, and abundance of the red bat, Lasiurus borealis. Journal of Mammalogy 50:209-212. Mumford, R. E. 1973. Natural History of the red bat (Lasiurus borealis) in Indiana. Periodicum Biologorum 75:155-158. Neubaum, D. J. 2005. Records of the eastern red bat on the northern Front Range of Colorado. Prairie Naturalist 37:41-42. Walsh (Walsh Environmental Scientists and Engineers, LLC). 2013. Post- Construction Bird and Bat Fatality Study Phase I Colorado Highlands Wind Project Logan County, Colorado In U.S. Department of Energy, Western Area Power Administration. 2009. Draft Supplemental Environmental Assessment DOE/SEA-1611-S1 Request for Modification of Interconnection Agreement for the Colorado Highlands Wind Project, Logan County, Colorado. https://energy.gov/nepa/downloads/ea-1611-s1-draft-supplemental-environmental-assessment. Accessed March 2018.

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FRINGED MYOTIS (MYOTIS THYSANODES)

Prepared by Mark A. Hayes (2017)

DESCRIPTION

Fringed myotis (Myotis thysanodes), a member of the Vespertilionidea family, is a medium to large myotis with large ears. The key feature that distinguishes this from other myotis species in Colorado is the prominent fringe of short hairs on the trailing edge of the tail membrane (Armstrong et al. 2011). This species can be confused with other myotis species, especially little brown myotis (M. lucifugus) and long-eared myotis (M. evotis). Care should be used in differentiating these species and beginners will benefit from Fringed myotis tail. Photo by D. Neubaum use of a key, such as the key to vespertilionid species in Armstrong et al. (2011; pp. 312-313).

Typical measurements are: weight 6–7 g; forearm length 39–46 mm; length of ears 16–21 mm (Armstrong et al. 2011).

DISTRIBUTION

Fringed myotis is a western species that occurs in conifer forests, shrublands, and canyonlands at moderate elevations to about 2500 m (O’Farrell and Studier 1980). Colorado occurrence records suggest a geographic distribution that bifurcates around the Southern Rocky Mountains, with separate populations occurring in a band along the Colorado Front Range and in western Colorado (Armstrong et al. 2011; Hayes 2011). Occurrence records suggest that the high peaks and higher elevation mountain parks of the Southern Rocky Mountains act as dispersal barriers and that movement by fringed myotis from east to west, and vice versa, across the Colorado Rockies is not likely to occur regularly (Hayes 2011). In Colorado this species is regularly captured in suitable habitat. Hayes (2011) and Hayes and Adams (2014) provide a detailed review of its geographic distribution in Colorado.

NATURAL HISTORY

In eastern Colorado, the fringed myotis occurs in mid- elevation forests along the Front Range from New Mexico to Wyoming, and occurs in the high plains and southwestern tablelands where there are suitable roosting resources available in rock features and other structures (Hayes 2011). For example, in northeastern Colorado this species has been captured near Pawnee Buttes, in and near the Pawnee

Fringed myotis. Photo by K. Navo National Grasslands. In southeastern Colorado, fringed myotis

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has been documented in the canyons of the Purgatoire River and near Mesa de Maya and Black Mesa. In western Colorado, fringed myotis have been documented throughout the Colorado Plateau region of extreme western Colorado. The species has been documented in mid- elevation forests, such as the forests around Pagosa Springs, and is expected to occur in mid-elevation forests throughout most of western Colorado. Males and females breed either during autumn or winter when bats are in hibernation sites

(O’Farrell and Studier 1980; Armstrong 2011). During spring, Potential distribution of fringed myotis in Colorado. adult females move to and aggregate in maternity colonies The map was generated using landscape-scale coefficients and known locations in MaxEnt to model where reproductive females give birth to and raise pups. predictive probability of occurrence surfaces. Females usually give birth to 1 pup, though twins have occasionally been observed. Pups are born during the summer months (e.g., early July). In Colorado, maternity colonies have been observed in rock crevices, abandoned mines, and human structures, such as cabins (O’Shea et al. 2011; Hayes and Adams 2015; Neubaum 2017). This species is often observed forming maternity colonies in tree snags in other parts of western North America (O’Farrell and Studier 1980), but maternity colonies have not yet been observed in these features in Colorado. Little is known in Colorado about where adult males roost during the summer maternity period. Likewise, little is known about where fringed myotis spends the winter months in Colorado, or where this species roosts during autumn. Fringed myotis in Colorado might use hibernation sites near maternity areas, or might undertake seasonal movements within or among nearby ecoregions. The detailed life history attributes of fringed myotis in North America are reviewed by O’Farrell and Studier (1980), and for Colorado are reviewed by Armstrong et al. (2011) and Hayes (2011).

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G4 S3 Tier 1 - SS SS - *See text on the first page of this section for an explanation of listing categories.

THREATS

Fringed myotis colonies and populations can be adversely impacted by human activities that reduce the availability of roosting resources or that disturb bats while they are roosting (Armstrong et al. 2011; Hayes and Adams 2015). Maternity colonies can be negatively affected by human activity inside roosting sites in caves and abandoned mines. Maternity colonies and other important roosting resources can be protected by installing bat compatible closures, such as bat gates, which allow bats to continue to use the site but keep unauthorized people from entering the site. Population modeling suggests that some bat populations would decrease substantially when exposed to future climate scenarios for western North America and Colorado (Hayes 2011). This change is attributed to the fact that temperate zone insectivorous bats usually give birth to only 1 pup per year when they are reproductively active and

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relatively small reductions in the proportion of female bats that are reproductive can result in rapidly decreasing populations. Thus, maintaining high quality maternity roosting resources, along with high quality foraging and water resources, should be a key element of bat conservation in arid regions of western North America. Fringed myotis is not yet known to be affected by white-nose syndrome. However, biologists and managers should remain vigilant in watching for signs of infection, as the fungal species that causes white-nose syndrome has only recently (in 2016) been recorded within the known range of fringed myotis.

GAPS IN KNOWLEDGE

Detailed information on the following is lacking for fringed myotis in Colorado: (1) the location and characteristics of hibernation sites; (2) proximity of summer roosting areas to winter roosting areas, and timing of seasonal movements; (3) the current population status in the eastern and western populations; (4) foraging behavior and home range sizes; (5) male roosting and life history characteristics; (6) the location and timing of breeding (e.g., does breeding take place at swarming sites during autumn, and/or inside hibernation sites during winter); (7) possible differential impacts of a changing climate in different parts of Colorado.

LITERATURE CITED Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011 Mammals of Colorado, second edition. University Press of Colorado. CPW (Colorado Parks and Wildlife). 2015. Colorado’s state wildlife action plan. Available: http://cpw.state.co.us/aboutus/Pages/StateWildlifeActionPlan.aspx. Accessed March 2018. Hayes, M. A. 2011. An analysis of fringed myotis (Myotis thysanodes), with a focus on Colorado distribution, maternity roost selection, and preliminary modeling of population dynamics. Dissertation, University of Northern Colorado. Hayes, M. A., and R. A. Adams. 2014. Geographic and elevational distribution of fringed myotis (Myotis thysanodes) in Colorado. Western North American Naturalist 74:446-455. Hayes, M. A., and R. A. Adams. 2015. Maternity roost selection by fringed myotis in Colorado. Western North American Naturalist 74:460-473. Neubaum, D. J. 2017. Bat Composition and Roosting Habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 - 2016. Colorado Parks and Wildlife, Grand Junction, CO. O’Farrell, M. J., and E. H. Studier. 1980. Myotis thysanodes. Mammalian Species 137:1-5. O'Shea, T. J., P. Cryan, E. A. Snider, E. W. Valdez, L. E. Ellison, and D. J. Neubaum. 2011. Bats of Mesa Verde National Park, Colorado: Composition, reproduction, and roosting habits. Monographs of the Western North American Naturalist 5:1-19.

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HOARY BAT (LASIURUS CINEREUS)

Prepared by Betsy C. Bolster Updated by Paul M. Cryan and Kevin T. Castle (2017)

DESCRIPTION

The Hoary bat (Lasiurus cinereus), a member of the family Vespertilionidae, can be distinguished from all other species by a combination of large size (forearm of 46–58 mm), frosted fur, golden coloration around the face, rounded ears, blunt tragus and furred uropatagium.

The measurements of the Hoary bat as described by Armstrong et al. (2011) are: wingspan of 380–410 mm; total length of 120–145 mm; tail length of 49–60 mm; ear length of Hoary bat. Photo by D. Neubaum 12.5–18.0 mm; forearm length of 46–56 mm; weight of 18–32 g.

DISTRIBUTION

The hoary bat is the widest ranging of all North American bats. This species is highly migratory and the North American subspecies (L. c. cinereus) seasonally ranges from Canada, southward through Mexico to at least Guatemala. The South American subspecies (L. c. villosissimus) may migrate attitudinally and occurs from Brazil to Argentina and Chile. Hoary bats also occur on several islands in the Hawaiian (L. c. semotus, listed as endangered under US Endangered Species Act of 1973) and Galapagos archipelagos. Hoary bats are infrequently captured during bat surveys throughout most of the eastern U.S., but can be captured in considerable numbers during certain seasons in the Rocky Mountains, Great Plains, and areas along the Pacific Coast. Hoary bats are associated with forested habitats wherever they occur, but are also found in areas lacking forest cover during migration periods. Although habitat requirements are not well understood, these bats may rely on deciduous riparian habitats in regions lacking other forests. This species seasonally occurs across much of Colorado, ranging from low-elevation canyonlands and grasslands up into (and perhaps above) coniferous forests of the mountains.

NATURAL HISTORY

Hoary bats are solitary and roost primarily in foliage of both coniferous and deciduous trees. Although few studies of roosting preference have been carried out, this species has been observed near the ends of branches 3–12 m above the ground, with roosts often being found at the edges of clearings. Some unusual roosting situations have been reported in caves, beneath a rock ledge, in a woodpecker hole, in a gray squirrel nest, under a driftwood plank, and clinging to the sides of buildings. Hoary bats are known to be highly migratory, sometimes moving distances greater than 2000 km and across a wide range of latitudes. It is thought that wintering sites are concentrated in California and Mexico. By

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summer, populations become widespread across much of North America, and may be segregated by sex. Individual males have been shown to make local or longer migrations, and have exhibited winter torpor bouts indicating that they may hibernate in trees in some parts of North America. Hoary bats are generally thought to be solitary but have been noted in flocks during late summer and autumn. Females embark on spring migration about 1 month earlier than males, and mating likely begins during late summer

Potential distribution of hoary bat in Colorado. The and autumn when previously disparate distributions of the map was generated using landscape-scale coefficients sexes begin to overlap. Females likely store sperm and delay and known locations in MaxEnt to model predictive probability of occurrence surfaces. fertilization until spring, but this has not been confirmed. Females migrate while pregnant and give birth from May through July in regions east of the Rocky Mountains. Females have from 1–4 pups annually, with 2 being the norm. This species tolerates a wide range of temperatures as illustrated by captures at air temperatures between 0 and 22oC. The ambient temperature at which individuals employ torpor also varies seasonally by sex. In one study, entry into torpor was observed to vary from 5–13oC. Hoary bats are thought to emerge late in the evening during summer, although they occasionally have been observed flying during late winter afternoons or just before sunset. Evening emergence and capture times range from just over 1 hour after sunset to after midnight. The swift, direct flight of this species makes it identifiable on the wing from all other U.S. bats except molossids. Hoary bats reportedly have a strong, possibly seasonal, preference for moths, but are also known to eat beetles, flies, grasshoppers, termites, dragonflies, and wasps. Reported predators include jays, kestrels, and snakes, and likely include hawks and owls as well.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G3G4 S3S4B Tier 2 - - SS - *See text on the first page of this section for an explanation of listing categories.

THREATS

Wind turbines pose a substantial threat to hoary bats in North America and Colorado, accounting for approximately half of the tens to hundreds of thousands of bat fatalities estimated to occur at wind energy facilities in the U.S. and Canada each year (Arnett and Baerwald 2013; Walsh 2013). Loss of roosting habitat due to timber harvest could potentially pose a threat to this species, but information on habitat needs are lacking. Use of pesticides on public forestlands may also be a potential source of mortality to roosting bats and their insect prey, but no data on the effects of pesticides on this species exist. In suburban settings, where jays thrive in association with humans, jays may pose a threat to sleeping or hibernating hoary bats.

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GAPS IN KNOWLEDGE

An improved understanding of why hoary bats are likely attracted to, and disproportionally struck by, wind turbines is needed. Mitigation of impacts from wind energy continues to necessitate novel innovations that will prevent strikes at these sites. The impact of current timber harvest practices on roosting and foraging is not well understood. Forest stand replacement from beetle kill may impact this bat.

LITERATURE CITED Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011 Mammals of Colorado, second edition. University Press of Colorado. Arnett, E. B., and E. F. Baerwald. 2013. Impacts of wind energy development on bats: implications for conservation. In: Adams RA, Pedersen SC (eds.) Bat evolution, ecology, and conservation. Springer, New York, p 435-456 Arnett, E. B., M. Schirmacher, M. M. P. Huso, and J. P. Hayes. 2009. Effectiveness of changing wind turbine cut-in speed to reduce bat fatalities at wind facilities. An annual report submitted to the Bats and Wind Energy Cooperative. Bat Conservation International. Barclay, R. M. R. 1985. Long- versus short-range foraging strategies of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats and the consequences for prey selection. Canadian Journal of Zoology, 63:2507-2515. Cryan, P. M. 2003. Seasonal distribution of migratory tree bats (Lasiurus and Lasionycteris) in North America. Journal of Mammalogy 84:579-593. Cryan, P. M., C. A. Stricker, and M. B. Wunder. 2014. Continental-scale, seasonal movements of a heterothermic migratory tree bat. Ecological Applications. 24:602-616. Cryan, P. M., J. W. Jameson, E. F. Baerwald, C. K. R. Willis, R. M. R. Barclay, E. A. Snider, and E. G. Crichton. 2012. Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines. PLoS ONE 7:e47586. Cryan, P. M., P. M. Gorresen, C. D. Hein, M. Schirmacher, R. Diehl, M. Huso, D.T.S. Hayman, P. Fricker, F. Bonaccorso, D. H. Johnston, K. Heist, and D. Dalton. 2014. Behaviors of bats at wind turbines. Proceedings of the National Academy of Sciences 111:15126-15131. Hayes, M. A., P. M. Cryan, and M. B. Wunder. 2015. Seasonally-dynamic presence-only species distribution models for a cryptic migratory bat impacted by wind energy development. PLoS ONE 10:e0132599. Hickey, C. B. 1990. Use of torpor by free-living Lasiurus cinereus. Bat Research News 30:67. Perkins, J. M., and S. P. Cross. 1988. Differential use of some coniferous forest habitats by hoary and silver-haired bats in Oregon. Murrelet, 69:21-24. Shump, K. A., Jr., and A. U. Shump. 1982. Lasiurus cinereus. Mammalian Species 185:1-5.

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Valdez, E. W. and Cryan, P. M. 2009. Food habits of the hoary bat (Lasiurus cinereus) during spring migration through New Mexico. The Southwestern Naturalist, 54(2):195-200. Walsh (Walsh Environmental Scientists and Engineers, LLC). 2013. Post- Construction Bird and Bat Fatality Study Phase I Colorado Highlands Wind Project Logan County, Colorado. in U.S. Department of Energy, Western Area Power Administration. 2009. Draft Supplemental Environmental Assessment DOE/SEA-1611-S1 Request for Modification of Interconnection Agreement for the Colorado Highlands Wind Project, Logan County, Colorado. Weller, T. J., Castle, K. T., F. Liechti, C. D. Hein, M. R. Schirmacher, and P. M. Cryan. 2016. First direct evidence of long-distance seasonal movements and hibernation in a migratory bat. Scientific Reports 6, 34585; doi: 10.1038/srep34585.

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LITTLE BROWN MYOTIS (MYOTIS LUCIFUGUS)

Prepared by William E. Rainey Updated by Tanya A. Dewey and Daniel J. Neubaum (2017)

DESCRIPTION

The little brown myotis (Myotis lucifugus) is a medium size Myotis species that lacks a calcar and has moderate length pointed ears with a blunt tragus. Pelage color may be multiple shades of brown, and the fur is typically longer, darker, and glossier than sympatric species. In the northwest U.S., external morphology and skull characters are insufficient to reliably assign a small percentage of individuals to M. lucifugus or the similar M. yumanensis, but intermediate individuals in southwest British Columbia were identifiable to species on biochemical characters. Some individuals in southern Colorado and northern New Mexico may be confused with M. yumanensis whom they overlap with in pelage and forearm measurements, and are intermediate in skull characters with M. occultus (with which they are sometimes synonymized). Body size (and time to maturity) increases with latitude. Little brown myotis. Photo by J. Gore The measurements of the little brown myotis as reported in Armstrong et al. (2011) and Harvey et al. (2011) are: total length 90–100 mm; tail 36–47 mm; hindfoot 8–10 mm; ear 11–15 mm, forearm 33–41 mm (usually 39–41 mm); wingspan 22–27 cm; weight 7–14 g.

DISTRIBUTION

The little brown myotis is among the most widespread and common bats in mesic, typically forested areas of temperate North America. Overall distribution extends from near the treeline in Canada and Alaska to the southern tier of the U.S. There is a distributional gap extending south from the largely treeless Great Plains through Texas. In the western U.S., this species is typically absent from hot, arid lowlands, but extends south (at increasing elevation) along forested mountain ranges into southern California, Nevada, Utah, and Colorado. The species likely occurs in New Mexico and Arizona as well but may be classified as Myotis occultus. However, this species is now generally thought to be a subspecies of M. lucifugus rather than a distinct species (Armstrong et al. 2011). In Colorado, this bat follows the broader descriptions above, with records throughout most forest types, commonly ranging from elevations above pinyon-juniper up to the subalpine (Storz and Williams 1996). On the Colorado West Slope the species is conspicuously absent from drier low elevation canyonlands where M. yumanensis commonly occurs. However, records for little brown myotis are common from lower elevation urban centers along the Front Range and have been collected along the Arkansas River as it crosses the southeastern plains as well. In addition, records of M. lucifugus and M. yumanensis overlap in the southeastern canyonlands.

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NATURAL HISTORY

Among woodland/forest bats, little brown myotis are an ecological generalist exploiting a wide variety of natural and man-made roost sites and a taxonomically wide spectrum of flying insect prey, including emerging adults of aquatic species. Summer maternity colony sites include tree cavities, rock crevices, caves, and anthropogenic structures. Fidelity to physically stable day and night roost sites is strong and individuals return for many years. Active season roosting by males and non-reproductive females is little studied, but male aggregations are known. Little brown myotis exhibit high summer roost and hibernacula fidelity, although they may switch sites between years. Females may relocate more than males, although genetic structure suggests high female philopatry in general. Populations may be highly structured, even regionally. Seasonal movements range widely between 10 and 647 km and are likely determined by winter roost resource availability in relation to the summer habitat. This species has been documented swarming at caves in Colorado (Navo et al. 2002) where mating may be occurring.

Hibernation sites (historically described from caves and abandoned mines) and seasonality have been studied in eastern and mid-continent populations, but are poorly known in western North America. Cave and mine surveys across western North America do not appear to house large colonies of this species. Surveys at thousands of abandoned mines in Colorado from 1990– 2009 documented only 43 little brown myotis roosting in mines, and the most documented in a mine at one time was only 15 bats roosting in the summer (K. Navo, pers. comm. 2016). Johnson et al. (2017) tracked little brown myotis to rock crevices in the autumn in Yellowstone National Park. In Colorado, little brown myotis dispersing from a maternity colony using a building near Carbondale moved to other Potential distribution of little brown myotis in buildings with smaller numbers of bats, as well as aspen Colorado. The map was generated using landscape- scale coefficients and known locations in MaxEnt to trees and rock crevices. Microclimate analysis of these model predictive probability of occurrence surfaces. autumn roosts suggest that buildings and trees may assist bats in the use of daily torpor and allow passive rewarming each afternoon as food resources remain available, while rock crevices would serve as suitable hibernacula (Neubaum 2018).

Although little brown myotis at the northern limits of their range face substantial challenges related to obtaining energy reserves as body mass prior to hibernation, northern populations have a lower than expected fueling rate but achieve high body masses prior to hibernation. This suggests regional variation in physiological and behavioral strategies in preparation for hibernation. For example, populations at their northernmost limits may switch to unusual prey items compared to more southern populations, such as orb weaver spiders rather than flying insects. Neubaum (2018) suggested that this species may be capitalizing on food resources such as miller moths and ice crawlers that occur on talus slopes in large aggregations during early autumn in Colorado due to their extremely high body fat. Daily foraging movements in summer tend to range from 1–10 km. Seasonal movements between summer maternity

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colonies and hibernacula can vary widely and may involve larger distances depending on resource availability. In Colorado, Neubaum (2018) found little brown myotis moved short distances of only 2–4 km between summer roosts and potential hibernacula.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G3 S4 Tier 1 - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

The primary threat to little brown myotis currently is the introduced fungal disease, white-nose syndrome (WNS; see chapter VII. Bats and Disease). This species has seen the largest declines in local populations of any bat in North America as of 2017. Mortality in some little brown myotis roosts in eastern North America has been documented as high as 99% and local populations have been reduced by up to 95% in those areas. Low levels of resistance have been detected in infected populations, with some individuals persisting despite Pseudogymnoascus destructans (fungal species that is causal agent of WNS) infected roosts. Individuals that survive WNS show evidence of physiological stress well beyond the infection. The resultant higher cortisol levels in these little brown myotis may additionally impact survival and fitness even for bats that have recovered. A status review by Kunz and Reichard (2010) concluded that the species warrants an endangered listing under the Endangered Species Act, 16 USC. §§ 1531- 1544, due to population declines associated with WNS.

Mortality at wind turbines may be another source of mortality in areas with wind farms. Approximately 13% of bat mortality at wind turbines in Canada was M. lucifugus. However, few records of little brown myotis overlap from the eastern plains of Colorado where most wind farms are currently situated. Other threats may include habitat and roost site disruptions, such as alterations in snag density and recruitment from timber harvest, agricultural or residential habitat conversion, or riparian forest alteration for flood control. This species often occupies structures and is vulnerable to extermination or improper exclusion practices. Large aggregations of this species hibernate in abandoned mines in eastern and central North America, therefore closure of mines without adequate survey could have population impacts; however, this species is rarely documented in these features in Colorado, especially during the winter.

GAPS IN KNOWLEDGE

Knowledge of hibernation sites and the degree of population aggregation at these sites in Colorado is lacking for this widespread species. Inadequate systematic resolution may affect management decisions (e.g., the status of M. occultus). Isolated populations in montane forest islands may be sufficiently differentiated to deserve taxonomic examination. Interspecific competition and range partitioning with sympatric species such as M. yumanensis and M. volans should be examined.

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LITERATURE CITED Adams, R. A. 1990. Biogeography of bats in Colorado - ecological implications of species tolerances. Bat Research News 31:17-21. Alves D. M. C. C, L. C. Terribile, and D. Brito. 2014. The potential impact of white-nose syndrome on the conservation status of North American bats. PLoS One 9(9): e107395. doi: 10.1371/journal.pone.0107395. Armstrong, D. M. J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of Colorado. Denver, Colorado. Boyles, J. G., L. P. McGuire, E. Boyles, J. P. Reimer, C. Brooks, R. W. Rutherford, T. A. Rutherford, J. O. Whitaker, and G. F. McCracken. 2016. Physiological and behavioral adaptations in bats living at high latitudes. Physiology and Behavior 165: 322-327. Carstens, B. C,. and T. A. Dewey. 2010. Species delimitation using a combined coalescent and information-theoretic approach: an example from North American Myotis bats. Systematic Biology 59(4): 400-414. Coleman, J. T. H., and J. D. Reichard. 2014. Bat white-nose syndrome in 2014: A brief assessment seven years after discovery of a virulent fungal pathogen in North America. Outlooks on Pest Management. doi: 10.1564/v25_dec_08 COSEWIC, Species at Risk Public Registry. 2017. Species profile: little brown myotis. Available online at: http://www.registrelep-sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=1173 Czense, Z. J., K. A. Jonasson, and C. K. R. Willis. 2017. Thrifty females, frisky males: winter energetics of hibernating bats from a cold climate. Physiological and biochemical zoology 90(4):502-511. Davy, C. M., G. F. Mastromonaco, J. L. Riley, J. H. Baxter-Gilbert, H. Mayberry, and C. Willis. 2017. Conservation implications of physiological carry over effects in bats recovering from white nose syndrome. Conservation Biology 31(3): 615-624. Dewey, T. A. 2006. Systematics and phylogeography of North American Myotis. Dissertation thesis, University of Michigan, Ann Arbor. Dixon, M. D. 2011. Population genetic structure and natal philopatry in the widespread North American bat Myotis lucifugus. Journal of mammalogy 92(6): 1343-1351. Fenton, M. B. and R. M. R. Barclay. 1980. Myotis lucifugus. Mammalian Species, 142:1-8. Harvey, M. J., J. S. Altenbach, and T. L. Best. 2011. Bats of the United States and Canada. The John Hopkins University Press, Baltimore. Herd, R. M., and M. B. Fenton. 1983. An electrophoretic, morphological, and ecological investigation of a putative hybrid zone between Myotis lucifugus and Myotis yumanensis (Chiroptera: Vespertilionidae). Canadian Journal of Zoology 61:2029-2050. Johnson, J. S., J. J. Treanor, M. J. Lacki, M. D. Baker, G. A. Falxa, L. E. Dodd, A. G. Waag, and E. H. Lee. 2017. Migratory and winter activity of bats in Yellowstone National Park. Journal of Mammalogy 98:211–221.

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Jones, J. K., D. M. Armstrong, R. S. Hoffmann, and C. Jones. 1982. Mammals of the northern Great Plains. University of Nebraska Press, Lincoln. 379 pp. Kunz, T. H., and J. D. Reichard. 2010. Status review of the little brown myotis (Myotis lucifugus) and determination that immediate listing under the Endangered Species Act is scientifically and legally warranted. Boston University. Available: http://www.bu.edu/cecb/files/2010/12/Final-Status- Review.pdf (December 2017). Langwig, K. E., J. R. Hoyt, K. L. Parise, W. F. Frick, J. T. Foster, and A. M. Kilpatrick. 2016. Resistance in persisting bat populations after white-nose syndrome invasion. Philosophical Transactions of the Royal Society 372: 2016.0044. Langwig, K. E., W. F. Frick, J. R. Hoyt, K. L. Parise, K. P. Drees, T. H. Kunz, J. T. Foster, and A. M. Killpatrick. 2016. Drivers in variation of species impacts for a multi-host fungal disease of bats. Philosophical Transactions of the Royal Society 371. doi: 10.1098/rstb.2015.0456. McGuire. L. P., K. A. Muise, A. Shrivastav, and C. K. R. Willis. 2016. No evidence of hyperphagia during prehibernation in a northern population of little brown bats (Myotis lucifugus). Canadian Journal of Zoology 94(12): 821-827. Morales, A. E., N. D. Jackson, T. A. Dewey, B. C. O’Meara, and B. C. Carstens. 2017. Speciation with gene flow in North American Myotis bats. Systematic Biology, in press. Nagorsen, D. W. and R. M. Brigham. 1993. Bats of British Columbia. University of British Columbia Press, Vancouver. Navo, K. W., S. G. Henry, and T. E. Ingersoll. 2002. Observations of swarming by bats and band recoveries in Colorado. Western North American Naturalist 62:124-126. Neubaum, D. J. 2018. Unsuspected retreats: autumn roosts and presumed hibernacula used by little brown myotis in Colorado. Journal of Mammalogy submitted. Norquay, K. J. O., F. Martinez-Nuez, J. E. Dubois, K. M. Monson, C. K. R. Willis. 2013. Long distance movements of little brown bats (Myotis lucifugus). Journal of Mammalogy 94(2):506-515. O'Shea, T. J., P. Cryan, E. A. Snider, E. W. Valdez, L. E. Ellison, and D. J. Neubaum. 2011. Bats of Mesa Verde National Park, Colorado: Composition, reproduction, and roosting habits. Monographs of the Western North American Naturalist 5:1-19. Powers, K. E., R. J. Reynolds, W. Ornodorff, W. M. Ford, and C. S. Hobson. 2015. Post white-nose syndrome trends in Virginia’s cave bats, 2008-2013. Journal of Ecology and the Natural Environment 7: 113-123. Storz, J. F., and C. F. Williams. 1996. Summer population structure of subalpine bats in Colorado. The Southwestern Naturalist 41:322-324. Thomas, D. W., and S. D. West. 1991. Forest age associations of bats in the southern Washington Cascade and Oregon coast ranges. US Forest Service. General Technical Reports PNW 295-303. USFWS, Environmental Conservation Online System. 2017. Species profile for little brown bat (Myotis lucifugus). Available online at: http://ecos.fws.gov/ecp0/profile/speciesProfile?sId=9051

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van Zyll de Jong, C. G. 1985. Handbook of Canadian Mammals. Vol. 2: Bats. National Museum of Natural Sciences, Ottawa. 212 pp. Verant, M. L., C. U. Meteyer, J. R. Speakman, P. M. Cryan, J. M. Lorch, and D. S. Blehert. 2014. White- nose syndrome initiates a cascade of physiologic disturbances in the hibernating bat host. BMC Physiology 14:10. Vonhof, M. J., A. L. Russell, and C. M. Miller-Butterworth. 2015. Range-wide genetic analysis of little brown bat (Myotis lucifugus) populations: estimating the risk of spread of white-nose syndrome. PLoS One. doi: 10.1371/journal.pone.0128713

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LONG-EARED MYOTIS (MYOTIS EVOTIS)

Prepared by Michael A. Bogan, Ernest W. Valdez, and Kirk W. Navo Updated by Tanya A. Dewey (2017)

DESCRIPTION

The long-eared myotis (Myotis evotis), a member of the family Vespertilionidae, has pale brownish to straw-colored pelage. It is distinguished from the southwestern myotis (M. auriculus) and the fringed myotis (M. thysanodes) by having long, glossy black ears and no distinct fringe of hairs along the edge of the uropatagium.

The measurements of the long-eared myotis as reported in

Armstrong et al (2011) are: total length of 88–92 mm; length Long-eared myotis. Photo by D. Neubaum of tail 41–46 mm; ear length of 18–23 mm; forearm length of 35–41 mm; wingspan of 25–30 mm; weight of 5–7 g.

DISTRIBUTION

The long-eared myotis ranges across western North America from southwestern Canada (British Columbia, Alberta and Saskatchewan) to Baja California and eastward in the U.S. to the western Great Plains. In Colorado this species is widely distributed across forested habitat from the canyonlands of the West Slope, through the central mountains, and east to the Front Range. Records for the long-eared myotis are lacking from the canyonlands of the southeastern portion of the state unlike those noted for several other myotis species documented there. Elevations as high as 3100 m in subalpine habitat have been documented for this bat (Storz and Williams 1996).

NATURAL HISTORY

The long-eared myotis eats moths and small beetles, as well as flies, lacewings, wasps, caterpillars, and true bugs. In areas where M. evotis and M. auriculus are sympatric, M. evotis tends to eat more beetles. Habitats used for foraging by long-eared myotis increase with increasing precipitation. This species is a slow flier and is often described as a hovering gleaner that feeds by eating prey off foliage, tree trunks, rocks, and from the ground. It generally leaves its roost for foraging after dark, but individuals have been Potential distribution of long-eared myotis in Colorado. caught as early as half an hour after sunset. Long-eared The map was generated using landscape-scale coefficients and known locations in MaxEnt to model myotis seem to spend more time foraging in a night than predictive probability of occurrence surfaces.

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sympatric species, at least in portions of their range, with one study suggesting they spend only 10% of nightly foraging time resting. Females give birth to one young in early summer. Individuals have lived up to 22 years. M. evotis is usually associated with coniferous forests, but also occurs in semiarid shrublands, sage, chaparral, and agricultural areas. Individuals roost under exfoliating tree bark and in hollow trees, stumps, logs, caves, mines, cliff crevices, boulders, sinkholes, and rocky outcrops on the ground. M. evotis is the fourth most documented species using abandoned mines in Colorado. They also sometimes roost in buildings and under bridges. During the summer, females form small maternity colonies, whereas males and non-reproductive females roost alone or in small groups nearby. In western Colorado, Chung-Macoubrey (2008) tracked 2 females to rock crevices in boulders, a cliff, and 2 juniper trees in the Book Cliffs north of Grand Junction. Efforts to track M. evotis in Mesa Verde National Park yielded similar results with the majority of bats using rock crevices in large boulders or cliffs (Snider et al. 2013). Two females from this study also roosted in both live and dead juniper trees and a downed log. In coniferous forest, this species was found using rock crevices and a house in the foothills adjacent to the Front Range (Adams 2002). Reproductive females use different roosting strategies in different habitats. In areas with rock crevices, females selected those roosts over other available resources, such as trees, because they are structurally more stable, and remain warmer so they do not necessitate the use of torpor. In areas without warm roosts, such as those where primarily snag roosts are available, females use torpor to manage energy budgets more frequently. Non- reproductive individuals use torpor more extensively to manage energy budgets than do reproductive females, which influences roost use by different members of a population. Long-eared myotis exhibit low roost fidelity, switching roosts frequently, but have small home ranges and thus demonstrate fidelity to a roosting area. Presumably, most individuals of this species hibernate in Colorado during the winter, although very few records have been collected to date.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G5 S4 - - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

The long-eared myotis may be affected by closure of abandoned mines without surveys, recreational climbing, some forest-management practices, and other activities (such as highway construction, water impoundments, blasting of cliffs for avalanche control) that impact cliff faces or rock outcrops. Wildfires may lead to siltation and loss of small ephemeral pools often used by this species, which is adapted to using cluttered environments in forested settings.

GAPS IN KNOWLEDGE

Little or no information is known on population trends, winter roosting requirements, winter range, importance of snags as summer roosts, and use and acceptance of bat gates. More information is also

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needed on foraging requirements. Genetic analyses of M. evotis throughout their range suggest that this species may be composed of multiple, independent evolutionary lineages. Cryptic diversity in M. evotis, M. thysanodes, and M. lucifugus suggests a complex, recent evolutionary history that has not been thoroughly documented and that has widespread management implications as white-nose syndrome moves westward across the continent.

LITERATURE CITED Adams, R. A. 2002. 2002 Final report: census and radio telemetry of bats at Heil Valley Ranch. University of Northern Colorado. Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of Colorado. Denver, Colorado. Arnett, E. B. and J. P. Hayes. 2009. Use of conifer snags as roosts by female bats in western Oregon. Journal of Wildlife Management 73(2): 214-225. Bogan, M. A. 1999. Myotis evotis. Pp. 88-90 in The Smithsonian Book of North American Mammals (D. E. Wilson and S. Ruff, eds.). Smithsonian Press, Washington, D.C. 750 pp. Carstens, B. C., and T. A. Dewey. 2010. Species delimitation using a combined coalescent and information-theoretic approach: an example from North American Myotis bats. Systematic Biology 59(4): 400-414. Chruszcz, B. J. and R. M. R. Barclay. 2003. Prolonged foraging bouts of a solitary gleaning/hawking bat, Myotis evotis. Canadian Journal of Zoology 81(5): 823-826. Chung-MacCoubrey, A. L. 2008. Book Cliff survey for BLM sensitive bats. USDA Forest Service-Rocky Mountain Research Station. Report Interagency Agreement No. BLM-IA #06-IA-11221602-150. Faure, P. A. and R. M. R. Barclay. 1992. The sensory basis of prey detection by the long-eared bat, Myotis evotis, and the consequences for prey-selection. Animal Behaviour 44(1): 31-39. Faure, P. A. and R. M. R. Barclay. 1994. Substrate-gleaning versus aerial-hawking: plasticity in the foraging and echolocation behaviour of the long-eared bat, Myotis evotis. Journal of Comparative Physiology, 174:651-660. Faure, P. A., J. H. Bullard, and R. M. R. Barclay. 1990. The response of tympanate moths to echolocation calls of a substrate gleaning bat, Myotis evotis. Journal of Comparative Physiology 166(6): 843-849. Gannon, W. L. and G. R. Racz. 2006. Character displacement and ecomorphological analysis of two long- eared Myotis (M. auriculus and M. evotis). Journal of Mammalogy 87(1): 171-179. Geluso, K. N. and K. Geluso. 2012. Effects of environmental factors on capture rates of insectivorous bats, 1971-2005. Journal of Mammalogy 93(1): 161-169. Manning, R. W. 1993. Systematics and evolutionary relationships of the long-eared myotis, Myotis evotis (Chiroptera: Vespertilionidae). Special Publications, The Museum, Texas Tech University No. 37, 1- 58pp. Manning, R. W. and J. K. Jones, Jr. 1989. Myotis evotis. Mammalian Species, 329:1-5.

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Morales, A. E., N. D. Jackson, T. A. Dewey, B. C. O’Meara, and B. C. Carstens. 2017. Speciation with gene flow in North American Myotis bats. Systematic Biology, in press. Nixon, A. E., J. C. Gruver, and R. M. R. Barclay. 2009. Spatial and temporal patterns of roost use by western long-eared bats (Myotis evotis). American Midland Naturalist 162(1): 139-147. Snider, E. A., P. M. Cryan, and K. R. Wilson. 2013. Roost selection by western long-eared myotis in burned and unburned pinon-juniper woodlands of southwestern Colorado. Journal of Mammalogy 94(3): 640-649. Solick, D. I. and R. M. R. Barclay. 2006a. Thermoregulation and roosting behavior of reproductive and nonreproductive female western long-eared bats (Myotis evotis) in the Rocky Mountains of Alberta. Canadian Journal of Zoology 84(4): 589-599. Solick, D. I. and R. M. R. Barclay. 2006b. Morphological differences among western long-eared Myotis populations in different environments. Journal of Mammalogy 87(5): 1020-1026. Solick, D. I. and R. M. R. Barclay. 2007. Geographic variation in the use of torpor and roosting behavior of female western long-eared bats. Journal of Zoology 272(4): 358-366. Storz, J. F., and C. F. Williams. 1996. Summer population structure of subalpine bats in Colorado. The Southwestern Naturalist 41:322-324. Vonhof, M. J. and R. M. R. Barclay. 1996. Roost-site selection and roosting ecology of forest-dwelling bats in southern British Columbia. Canadian Journal of Zoology 74:1797-1805. Vonhof, M. J. and R. M. R. Barclay. 1997. Use of tree stumps as roosts by the western long-eared bat. Journal of Wildlife Management 61:674-684. Waldien, D. L. and J. P. Hayes. 2001. Activity areas of female long-eared Myotis in coniferous forests in western Oregon. Northwest Science 75(3): 307-314. Wilson, J. M. and R. M. R. Barclay. 2006. Consumption of caterpillars by bats during an outbreak of spruce budworm. American Midland Naturalist 155(1): 244-249.

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LONG-LEGGED MYOTIS (MYOTIS VOLANS)

Prepared by Michael A. Bogan, Ernest W. Valdez, and Kirk W. Navo Updated by Tanya. A. Dewey and Daniel. J. Neubaum (2017)

DESCRIPTION:

The long-legged myotis (Myotis volans), a member of the family Vespertilionidae, is recognized by its short rounded ears, small hind feet, long tibia, distinctly keeled calcar, and long, dense fur on the underside of the wing membrane that extends from the body to a line joining the elbow and the knees. Although some variation in color exists, it is typically dark brown.

The measurements of the long-legged myotis as reported in

Armstrong et al. (2011) are: total length 95–108 mm; tail Long-legged myotis. Photo by K. Navo length 40–43 mm; length of ear 11–14 mm; forearm length 35–41 mm; wingspan 25–30 mm; weight 8–10 g.

DISTRIBUTION

The long-legged myotis ranges across western North America from southeastern Alaska, British Columbia and Alberta to Baja California and central Mexico. It occurs throughout the western U.S. from the Pacific coast to the Great Plains and central Texas. Elevational distribution is from sea level to 3600 m. In Colorado, the species occurs throughout much of the state where coniferous forests are found, including into the more arid lower elevation canyonlands of the Western Slope where pinyon-juniper forest exists.

NATURAL HISTORY

The long-legged myotis is a bat primarily of coniferous forests, but also occurs seasonally in riparian and desert habitats. Use of the later habitat may be regulated somewhat in this species by its relatively poor ability to concentrate urine. However, this bat was the most frequently captured species during surveys at Mesa Verde National Park (O’Shea et al. 2011). Adams et al. (2003) suggested that water sources may play an important role as sources of supplemental calcium for female long-legged myotis. This species uses abandoned buildings, cracks in the ground, cliff and rock crevices, exfoliating tree bark, and hollows within snags as summer day roosts. Caves and mine tunnels have been used as hibernacula although these roosts have not been regularly identified across much of this species range. In Colorado, this is the second most frequently documented species using abandoned mines, and the most common species using mines above 3125 m. Most records at high elevations were documented in late August and early September suggesting these sites may be transitional in nature. Numerous records of M. volans have

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been documented during swarming at high elevation caves in Colorado. Gravid and lactating females vary their use of roosts according to physiological needs. Appropriate snag roosts may persist in forests for only a few years. Both of these findings suggest that forests should be managed for diversity of trees and large snags to accommodate successful reproduction and population persistence. Roost sites may be chosen to minimize energy loss, with cooler temperatures in roosts in the morning aiding in torpor and

warmer temperatures later in the day acting to passively Potential distribution of long-legged myotis in Colorado. The map was generated using landscape- warm bats before their active period. In Colorado, the long- scale coefficients and known locations in MaxEnt to model predictive probability of occurrence surfaces. legged myotis was radio tracked predominantly to rock crevices in high cliff faces at Mesa Verde National Park and Colorado National Monument (O’Shea et al. 2011; Neubaum 2017). This species was biased towards using higher elevation locations in Colorado National Monument but more evenly dispersed in Mesa Verde National Park which, on average, is composed of higher elevations than the former.

The long-legged myotis is active throughout the night, but peak activity is 3–4 hours after sunset. It is a rapid, direct flier, often traveling some distance while foraging, and feeds in and around the forest canopy, primarily on moths and other soft-bodied insects. In north-central Idaho, habitats used were those with the highest frequencies of lepidopterans, which made up 49.2% of the diet. Coleopterans made up 31.1% of the diet in that area. Some studies suggest no difference in habitat use between males and pregnant or lactating females. However, O’Shea et al. (2011) found sex ratios to be skewed towards reproductive females in Mesa Verde. Individuals copulate in autumn, with females storing the sperm over the winter, ovulating in the spring, and giving birth from May–August. Individuals have lived a maximum of 21 years.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G4G5 S5 - - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

Threats from climate change and catastrophic wildfire may have potential to impact local populations of this species through loss of roost structures and water sources. Forest management practices in pine forests, such as those to manage beetle kill, areas of heavy timber harvesting, or large scale treatments, have some potential to affect this bat, particularly in areas where rock crevice resources are less available and trees are selected as roosts. Long-legged myotis may be affected by closure of abandoned mines without adequate surveys. Residues of DDT and its metabolites have been found in this species in

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Oregon. Extermination and exclusion of large maternity colonies from rural buildings within forested settings occurs periodically.

GAPS IN KNOWLEDGE

No information known on population trends or use and acceptance of bat gates is available. More information is needed on roosting habits, particularly hibernacula, and foraging requirements throughout the range of this species. No comprehensive study of genetic variation in this widespread species has been published. Impacts to populations of this species from large scale forest alterations such as beetle kill and wildfire need to be investigated.

LITERATURE CITED Adams, R. A., S. C. Pedersen, K. M. Thibault, J. Jadin, and B. Petru. 2003. Calcium as a limiting resource to insectivorous bats: can water holes provide a supplemental mineral source? Journal of Zoology 260:189-194. Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of Colorado. Denver, Colorado. Baker, M. D., and M. J. Lacki. 2006. Day-roosting habitat of female long-legged myotis in ponderosa pine forests. Journal of Wildlife Management 70(1): 207-215. Bogan, M. A., et al. 1997. A study of bat populations at Los Alamos National Laboratory and Bandelier National Monument, Jemez Mountains, New Mexico. Unpublished report to Cooperators, US Geological Survey, Biological Resources Division, Albuquerque. 76 pp., and appendices. Cryan, P. M., M. A. Bogan, and G. M. Yanega. 2001. Roosting habits of four bat species in the Black Hills of South Dakota. Acta Chiropterologica 3(1):43-52. Findley, J. S., A. H. Harris, D. E. Wilson, and C. Jones. 1975. Mammals of New Mexico. University of New Mexico Press. Albuquerque. 360 pp. Geluso, K. N. 1978. Urine concentrating ability and renal structure of insectivorous bats. Journal of Mammalogy 59: 312-323. Herder, M. J., and J. G. Jackson. 2000. Roost preferences of long-legged myotis in northern Arizona. Transactions of the Western Section of the Wildlife Society. Johnson, J. S., M. J. Lacki, and M. D. Baker. 2007. Foraging ecology of long-legged myotis (Myotis volans) in north-central Idaho. Journal of Mammalogy 88(5): 1261-1270. Lacki, M. J., M. D. Baker, and J. S. Johnson. 2012. Temporal dynamics of roost snags of long-legged myotis in the Pacific Northwest, USA. Journal of Wildlife Management 76(6): 1310-1316. Lacki, M. J., J. S. Johnson, and M. D. Baker. 2013. Temperatures beneath bark of dead trees used as roosts by Myotis volans in forests of the Pacific Northwest, USA. Acta Chiropterologica 15(1): 143- 151. Lacki, M .J., J. S. Johnson, and L. E. Duke. 2007. Prey consumption of insectivorous bats in coniferous forests of north-central Idaho. Northwest Science 81(3): 199-205.

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Neubaum, D. J. 2017. Bat Composition and Roosting Habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 - 2016. Colorado Parks and Wildlife, Grand Junction, CO. Ober, H. K., and J. P. Hayes. 2008. Prey selection by bats in forests of western Oregon. Journal of Mammalogy 89(5): 1191-1200. Ormsbee, P. C. 1996. Characteristics, use, and distribution of day roosts selected by female Myotis volans (long-legged myotis) in forested habitat of the central Oregon Cascades. Pp. 124-131 in Bats and Forest Symposium, (R. M. R. Barclay and M. R. Brigham, eds.), October 19-21, 1995, Victoria, British Columbia. Research Branch, B. C. Ministry of Forests, Victoria. Working Paper 23/1996. Ormsbee, P. C., and W. C. McComb. 1998. Selection of day roosts by female long-legged myotis in the central Oregon Cascade range. Journal of Wildlife Management 62(2): 596-603. O'Shea, T. J., P. Cryan, E. A. Snider, E. W. Valdez, L. E. Ellison, and D. J. Neubaum. 2011. Bats of Mesa Verde National Park, Colorado: Composition, reproduction, and roosting habits. Monographs of the Western North American Naturalist 5:1-19. Parker, D. I., J. A. Cook, and S. W. Lewis. 1996. Effects of timber harvest on bat activity in southeastern Alaska’s temperate rainforests. Pp. 277-292 in Bats and Forest Symposium, (R. M. R. Barclay and M. R. Brigham, eds.), October 19-21, 1995, Victoria, British Columbia. Research Branch, B. C. Ministry of Forests, Victoria. Working Paper 23/1996. Saunders, M. B., and R. M. R. Barclay. 1992. Ecomorphology of insectivorous bats – a test of predictions using two morphologically similar species. Ecology 73(4): 1335-1345. Warner, R. M. and N. J. Czaplewski. 1984. Myotis volans. Mammalian Species, 224:1-4.

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PALLID BAT (ANTROZOUS PALLIDUS)

Prepared by Robert A. Schorr (2017)

DESCRIPTION

The pallid bat (Antrozous pallidus) of the Vespertilionidae family is a large, pale, long-eared species. Color varies from pale creamy to light brown, with the under parts lacking darker-tipped hairs, thus appearing lighter on the ventral side. Their eyes are large, and the nose is surrounded by sebaceous glands that give it a blunt, hog-nosed appearance.

Measurement ranges are: total length 90–113 mm; tail length

40–47 mm; hindfoot length 10–12 mm; ear length 23–37 mm; Pallid bat. Photo by D. Neubaum forearm length 48–60 mm; and wingspan 37–41 mm, and body mass 14–17 g (Armstrong et al. 2011).

DISTRIBUTION

The range of the pallid bat extends from southern British Columbia to central Mexico and east to central Kansas and Oklahoma. In Colorado this bat inhabits lower elevations of the Western Slope, broken rocky areas of the southeastern part of the state and along the foothills to Colorado Springs. A report of an isolated colony at Torrington (Stromberg 1982), on the plains of eastern Wyoming, suggests that the pallid bat could be found in rocky habitats or structures on the plains of eastern Colorado.

NATURAL HISTORY

This bat is a species of deserts, semiarid shrublands, montane shrublands, pinon-juniper woodlands, and riparian woodlands. Pallid bats roost in a variety of structures, including crevices of rocks, caves, mines, cavities of trees, and human-made structures (Twente 1955; Lewis 1994), but most records of roosts for pallid bats identify geologic features as the predominant roosting structure (O’Shea and Vaughan 1977; Lewis 1996; Schorr and Siemers 2013). In Colorado, the pallid bat occupies semidesert scrub and piñon- juniper woodlands to about 2200 m. Pallid bats are gregarious, although males may separate from breeding females in summer. Nursery colonies of adult females and young may number in the hundreds, whereas bachelor roosts may be as large as 100 adult males (Davis and Cockrum 1963; Vaughan and O’Shea 1976). Young male pallid bats may roost with maternity colonies, but adult males typically roost separately (Vaughan and O’Shea 1976; Hermanson and O’Shea 1983). Much of what is known of the roosting ecology of pallid bats is based on female groups or nursery colonies (Vaughan and O’Shea 1976; O’Shea and Vaughan 1977; Lewis 1996). The pallid bat's habit of using structures built by humans may allow it to extend beyond what would otherwise be its natural range. Roosting has been documented in burlap sacks, stone piles, large conifer snags (e.g., Ponderosa pine), inside basal hollows of redwoods

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and giant sequoias, and bole cavities in oaks (Racey 1933; Bailey 1936; Beck and Rudd 1960; Hermanson and O’Shea 1983).

This species is not thought to be migratory and makes only short movements to hibernation sites (Twente 1955). Pallid bats probably hibernate in Colorado from mid-October to April, although there is little evidence of their winter habits. Both day and night roosts change seasonally as their thermal characteristics change (Twente 1955; Vaughan and O’Shea 1976; O’Shea and Vaughan 1977; Lewis 1996). Mortality is highest in young bats, with approximately half surviving to their second year (Sidner 1997). Based on band Potential distribution of pallid bats in Colorado. The returns, only 10% survive to the age of 5 (Sidner 1997). map was generated using landscape-scale coefficients and known locations in MaxEnt to model predictive Records for longevity are 11 years old (Sidner 1997). probability of occurrence surfaces. Copulation occurs between October and December, and might extend as late as February (Orr 1954; Barbour and Davis 1969). Sperm are stored by the females until spring, when ovulation, fertilization and implantation occur (Orr 1954; Oxberry 1979). Gestation is about 9 weeks. Older females generally give birth to two young, whereas younger females have only one pup (Sidner 1997). Young are born in June and July, and the sex ratio of the newborns is 1:1. Young begin to fly between 28 and 35 days old and are completely weaned at 6–8 weeks. Mothers forage with the young until the young become independent (Orr 1954). The pallid bat feeds principally on flightless ground-dwelling arthropods, such as crickets, grasshoppers, beetles, scorpions and spiders (Bell 1982; Johnston and Fenton 2001) but also ingests nectar (Herrera et al. 1993; Frick et al. 2009) and small vertebrates, such as lizards, and small rodents (Bell 1982; Lenhart et al. 2010)

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G4 S4 - - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

This species use of mines suggests that some roosting locations may be in jeopardy because of the active efforts to close historic mining projects. Additional threats include human disturbance of roost sites, including vandalism within roost sites, roost site destruction, extermination in buildings, and pesticide use. Loss of tree roosts could occur through various forest harvesting and alteration activities, including commercial timber harvest (e.g., selective hardwood removal), and loss of oaks to suburban expansion or vineyard development. Although this species is believed to be tolerant of arid conditions and has the ability to conserve water through renal adaptations to concentrate urine (Geluso 1978), lack of access to open water for drinking can alter habitat use and could threaten viability in some regions.

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GAPS IN KNOWLEDGE

Data are lacking regarding seasonal movements (it is currently believed that they do not migrate long distances between summer and wintering sites). Additional information is required on winter activity patterns (i.e., roost sites, activity levels, etc.). More information is needed on roosting requirements in natural roosts (e.g., rock crevices and tree hollows).

LITERATURE CITED Armstrong, D. R., F. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado, 2nd ed. University of Colorado Press, Boulder. Bailey, V. 1936. The mammals and life zones of Oregon. North American Fauna 55:1-416. Barbour, R. W., and W. H. Davis. 1969. Bats of America. The University Press of Kentucky, 286 pp. Beck, A. J., and R. L. Rudd. 1960. Nursery colonies in the pallid bat. Journal of Mammalogy 41:266-267. Bell, G. P. 1982. Behavioral and ecological aspects of gleaning by a desert insectivorous bat, Antrozous pallidus (Chiroptera: Vespertilionidae). Behavioral Ecology and Sociobiology 10:217-223. Davis, R., and E. L. Cockrum. 1963. “Malfunction” of homing ability in bats. Journal of Mammalogy 44:131-132. Frick, W. F., P. A. Healy, III, and J. P. Hayes. 2009. Facultative nectar-feeding in a gleaning insectivorous bat (Antrozous pallidus). Journal of Mammalogy 90:1157-1164. Geluso, K. N. 1979. Urine concentrating ability and renal structure of insectivorous bats. Journal of Mammalogy 59:312-323. Hermanson, J. W., and T. J. O’Shea. 1983. Antrozous pallidus. Mammalian Species 213:1-8. Johnston, D. S., and M. B. Fenton. 2001. Individual and population-level variability in diets of pallid bats (Antrozous pallidus). Journal of Mammalogy 82:362-373. Lenhart, P. A., V. Mata-Silva, and J. D. Johnson. 2010. Foods of the pallid bat, Antrozous pallidus (Chiroptera: Vespertilionidae), in the Chihuahuan Desert of western Texas. Southwestern Naturalist 55:110-114. Lewis, S. E. 1994. Night roosting ecology of pallid bats (Antrozous pallidus) in Oregon. American Midland Naturalist 132:219-226. Lewis, S. E. 1996. Low roost fidelity in pallid bats: associated factors and effects on group stability. Behavioral Ecology and Sociobiology 39:335-344. Orr, R. T. 1954. Natural history of the pallid bat, Antrozous pallidus (LeConte). Proceedings of the California Academy of Sciences 28:165-246. O’Shea, T. J., and T. A. Vaughan. 1977. Nocturnal and seasonal activities of the pallid bat, Antrozous pallidus. Journal of Mammalogy 58:269-284. Oxberry, B. A. 1979. Female reproductive patterns in hibernating bats. Journal of Reproduction and Fertility 56:359-367.

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Racey, K. 1933. Pacific pallid bat in British Columbia. Murrelet 14:18. Schorr, R. A., and J. L. Siemers. 2013. Characteristics of roosts of male pallid bats (Antrozous pallidus) in southeastern Colorado. Southwestern Naturalist 58:470-474. Sidner, R. M. 1997. Studies of bats in southeastern Arizona with emphasis on aspects of life history of Antrozous pallidus and Eptesicus fuscus. PhD dissertation. University of Arizona, Tucson. Stromberg, M. R. 1982. New records of Wyoming bats. Bat Research News 23:42-44. Twente, J. W., Jr. 1955. Some aspects of habitat selection and other behavior of cavern-dwelling bats. Ecology 36:706-732. Vaughan, T. A., and T. J. O’Shea. 1976. Roosting ecology of the pallid bat, Antrozous pallidus. Journal of Mammalogy 57:19-42.

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SILVER-HAIRED BAT (LASIONYCTERIS NOCTIVAGANS)

Prepared by Jeremy Siemers (2017)

DESCRIPTION

The silver-haired bat is a medium-sized vespertilionid with black or dark brown silver-tipped hairs. The interfemoral membrane is partially furred on the dorsal surface. This bats ears are black, short and rounded with a blunt tragus.

The measurements of the silver-haired bat reported by Armstrong et al. (2011) are: total length 90–112 mm; tail 35– 48 mm; hindfoot 8–11 mm; ear 13–16 mm, forearm 37–44 mm; wingspan 27–32 cm; weight 7–15 g. Silver-haired bat. Photo by D. Neubaum

DISTRIBUTION

The silver-haired bat is found from southeastern Alaska, throughout southern Canada and most of the U.S. into the San Carlos Mountains of northeastern Mexico and southeast to Georgia. In Colorado, the silver-haired bat occurs statewide, especially during spring and autumn migrations. Most records are from the western two-thirds of the state. Bonewell et al. (2017) reported 5 winter records of silver- haired bats using abandoned mines in southwestern Colorado and 1 individual was found roosting on a building in Greeley in early December (Adams, pers. comm. in Armstrong et al. 2011), but other winter records of this species in the state are lacking.

Seasonal variations in locational records suggest considerable migration in some parts of the silver- haired bat’s range, with animals moving to warmer climates in the winter. Most animals from Colorado presumably winter in the southwestern U.S., but specific migration patterns and variation between sexes for Coloradoan silver-haired bats is unknown. Intraspecific variation in migration behavior in eastern North America has been shown, with evidence of leapfrog migration of some females and partial migration by both sexes (Fraser et al. 2017). In some subpopulations there appears to be summer segregation of the sexes. Summer records from Colorado are predominately male (Adams 1988; Bogan and Mollhagen 2010; Neubaum 2017).

NATURAL HISTORY

Range-wide, silver-haired bats are primarily forest bats, associated with conifer and mixed conifer/hardwood forests. Roosting sites are generally in older trees with cavities or sloughing bark that are taller than nearby trees (Perkins and Cross 1988; Campbell et al. 1996; Betts 1998). Both males and non-reproductive females change roosts frequently and use multiple roosts within a limited area throughout the summer (Mattson et al. 1996). Some records exist for roosts in other structures and these alternate structures appear to be used more frequently during migration and hibernation. In

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Colorado, there are records of this species using caves in the summer as night roosts (Siemers 2002) and mines during the winter (Bonewell et al. 2017). The author has also radio tracked one individual in the canyonlands of southwest Colorado during summer that day roosted in a juniper tree and rock crevice. During hibernation in other parts of its range, this species has been found in hollow trees, under sloughing bark, in rock crevices, and occasionally under wood piles, in leaf litter, under foundations, and in

Potential distribution of silver-haired bats in Colorado. buildings, mines and caves (Kunz 1982 and references The map was generated using landscape-scale therein). Silver-haired bats forage above the canopy, over coefficients and known locations in MaxEnt to model predictive probability of occurrence surfaces. open meadows, and in the riparian zone along watercourses. Although the species is known to take a wide variety of insects including beetles, flies, wasps, mayflies, chironomids, and isopterans, moths appear to be a major portion of their diet (Kunz 1982 and references therein). Silver-haired bats mate in the autumn (Cryan et al. 2012). Females form small nursery colonies and maternity roosts appear to be almost exclusively in trees -- inside natural hollows and bird-excavated cavities or under loose bark of large diameter snags (Mattson et al. 1996; Vonhof and Barclay 1996; Betts 1998). This species has a gestation period of 50–60 days and females usually give birth to twins in mid to late June (Druecker 1972; Kunz 1982). The young require over 36 days to become volant (Kunz 1982).

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G3G4 S3S4 - - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

The most significant threat to the silver-haired bat is wind energy development. This species is 1 of 3 migratory tree bats (see Species Accounts for hoary bat and eastern red bat) found killed at wind turbines most frequently in North America north of Mexico (Arnett et al. 2008). Arnett and Baerwald (2013) estimated 149,000–308,000 silver-haired bats were killed at wind energy facilities in the U.S. and Canada from 2000–2011. In Colorado, silver-haired bats have been found killed by wind turbines in the autumn in Logan County (Walsh 2013). Wind energy development is expected to expand significantly in Colorado, especially in the eastern half of the state (see section VIII. Energy Development).

Diagnostic symptoms of white-nose syndrome have not been confirmed in this species; however the causative fungus Pseudogymnoascus destructans (Pd) has been detected. A silver-haired bat submitted for rabies testing from Washington state in March 2016 tested positive for Pd, but no lesions indicative of WNS were present. This finding, coupled with similar reports from the eastern U.S., suggests this species may be a carrier of Pd.

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Other potential threats include loss of roosting habitat due to logging practices that fail to accommodate the roosting needs of this species (e.g., clusters of large snags, mature aspen with loose bark), loss of temporary roosts within migration routes, loss of foraging habitat in riparian areas, and reduction of prey base due to broadcast application of pesticides.

GAPS IN KNOWLEDGE

An improved understanding of the potential threat to silver-haired bats from wind turbines in Colorado is needed. More information is needed on the distribution of breeding populations, regional differences in roosting requirements, the timing and patterns of migration for each sex throughout the West, and the location of possibly important mating and migratory sites. Information is also needed on what factors (e.g., temperature, and local food availability) determine year-to-year and seasonal variation in local distribution and abundance. Further information on the role this species plays in the disease dynamics of white-nose syndrome is also needed.

LITERATURE CITED Adams, R. A. 1988. Trends in reproductive biology of some bats in Colorado. Bat Research News 29:21- 25. Armstrong, D. M. J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado, 2nd edition. Denver Museum of Nature and Science and University Press of Colorado, Boulder, CO. Arnett, E. B., and E. F. Baerwald. 2013. Impacts of wind energy development on bats: implications for conservation In R. A. Adams and S. C. Peterson (eds.) Bat Evolution, Ecology, and Conservation, 435- 455. Springer Science Press, New York, NY. Arnett, E. B., W. K. Brown, W. P. Erickson, J. K. Fiedler, B. L. Hamilton et al. 2008. Patterns of bat fatalities at wind energy facilities in North America. Journal of Wildlife Management 71:61-78. Barclay, R. M. R. 1985. Long- versus short-range foraging strategies of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats and the consequences for prey selection. Canadian Journal of Zoology 63:2507-2515. Betts, B. J. 1998. Roosts used by maternity colonies of Silver-hair Bats in northeast Oregon. Journal of Mammalogy 79:643-650. Bogan, M. A., and T. R. Mollhagen. 2010. Resurvey for bats (Chiroptera) at Dinosaur National Monument, Colorado/Utah, 2008-2009. Final report. Department of Biology, University of New Mexico and Natural History Associates. Bonewell, L. R., M. A. Hayes, N. LaMantia-Olson, E. Wostl, and K. W. Navo. 2017. Silver-haired bats associated with abandoned mines in Colorado provide insights into winter habitat and roost use. Western North American Naturalist 77:404-407. Campbell, L. A., J. G. Hallett, and M. A. O’Connell. 1996. Conservation of bats in managed forests: use of roosts by Lasionycteris noctivagans. Journal of Mammalogy 77:976-984.

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Cryan, P. M., J. W. Jameson, E. F. Baerwald, C. K. R. Willis, R. M. R. Barclay, E. A. Snider, and E. G. Crichton. 2012. Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines. PLoS One 7:e47586. Druecker, J. D. 1972. Aspects of reproduction in Myotis volans, Lasionycteris noctivagans, and Lasiurus cinereus. Ph.D. Dissertation, University of New Mexico, Albuquerque. Fraser, E. E., D. Brooks, and F. J. Longstaffe. 2017. Stable isotope investigation of the migratory behavior of silver-haired bats (Lasionycteris noctivagans) in eastern North America. Journal of Mammalogy 98:1225-1235. Kunz, T. H. 1982. Lasionycteris noctivagans. Mammalian Species 172:1- 5. Mattson, T. A., S. W. Buskirk, and N. L. Stanton. 1996. Roost sites of the silver-haired bat (Lasionycteris noctivagans) in the Black Hills, South Dakota. The Great Basin Naturalist 56:247-253. Neubaum, D. J. 2017. Bat composition and roosting habits of Colorado National Monument and McInnis Canyons National Conservation Area: 2014 - 2016. Colorado Parks and Wildlife, Grand Junction, CO. Perkins, J. M., and S. P. Cross. 1982. Sexual differentiation in migratory patterns of Lasionycteris noctivagans in Oregon and Washington. Paper presented to the 22nd annual North American Symposium on bat research, Austin, TX. Perkins, J. M., and S. P. Cross. 1988. Differential use of some coniferous forest habitats by hoary and silver-haired bats in Oregon. Murrelet, 69:21-24. Siemers, J. L. 2002. A survey of Colorado’s caves for bats. Colorado Natural Heritage Program Report. Vonhof, M. J., and R. M. R. Barclay. 1996. Roost-site selection and roosting ecology of forest-dwelling bats in southern British Columbia. Canadian Journal of Zoology 74:1797-1805. Walsh (Walsh Environmental Scientists and Engineers, LLC). 2013. Post-Construction Bird and Bat Fatality Study Phase I Colorado Highlands Wind Project Logan County, Colorado In U.S. Department of Energy, Western Area Power Administration. 2009. Draft Supplemental Environmental Assessment DOE/SEA-1611-S1 Request for Modification of Interconnection Agreement for the Colorado Highlands Wind Project, Logan County, Colorado. https://energy.gov/nepa/downloads/ea-1611-s1-draft-supplemental-environmental-assessment. Accessed September 2017.

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SPOTTED BAT (EUDERMA MACULATUM)

Prepared by Bob Luce Updated by Melissa Siders and Daniel J. Neubaum (2017)

DESCRIPTION:

The spotted bat (Euderma maculatum), a member of the family Vespertilionidae, is a medium-sized bat with enormous ears and a distinctive black dorsum with 3 large white spots. The venter has frosted appearance because the hairs have black bases and white tips. The ears are pink to gray-brown. White hairs are usually present at the posterior base of each ear (Armstrong et al. 2011)

The measurements of the spotted bat as reported in Armstrong et al. (2011) are: total length 107–119 mm; ear Spotted bat with distinct large white spots. Photo by K. Navo 37–47 mm, forearm 48–52 mm; wingspan 34–38 cm; weight 13–14 g.

DISTRIBUTION

The spotted bat ranges from southern British Columbia to Durango, Mexico. In the U.S. it is known from all states west of and including Montana, Wyoming, Colorado, New Mexico and Texas. Recent genetic work shows connected populations through the west (Canada to Mexico; Walker et al. 2014). Despite its broad geographic range, the ecology and population trends of this species are poorly understood owing to patchy distribution and low capture rates. While the spotted bats distribution is fairly broad, being found from extremely arid low elevation desert habitats to high elevation forests, it is highly associated with prominent rock features. In Colorado capture records for the species are limited to the canyonlands of the Western Slope where reproductive adults and juveniles have been collected in and around Dinosaur National Monument, the Grand, Sinbad, and Paradox Valley’s, and Mesa Verde National Park (D. Neubaum, unpublished data; O’Shea et al. 2011). Acoustic and audible calls have been collected at other locations associated with canyons across the state including at higher elevation sites in Colorado, like the Deep Creek area of the White River National Forest, but residency status of these individuals remains uncertain.

NATURAL HISTORY

Published descriptions of natural roosts used by spotted bats are few and most are general descriptions (e.g., cliff face). Until the mid-1990s, knowledge of spotted bats was primarily from the 3 locations where they had been captured most frequently: the Okanagan Valley in southern British Columbia, Big Bend National Park in southern Texas, and Fort Pierce Wash on the Utah–Arizona border. In the late

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1980s spotted bats were captured in subalpine meadows on the Kaibab Plateau (≥2500 m elevation) in northern Arizona and subsequently radio-tracked to roosts up to 43 km away in sheer cliffs of the Grand Canyon (≤1150 m elevation; Rabe et al. 1998). This behavior contrasted with the long-range foraging observations in British Columbia, where bats flew ≤10 km from day roosts to forage.

Spotted bats produce audible echolocation calls, in the range of 7.5–12 Khz, which are frequently used in audible detections for this species. Spotted bats, both male and female, have been documented roosting in colonies and Spotted bat. Photo by D. Neubaum singly. Multiple male spotted bats are known to use a cave site in Northern Arizona (Chambers et al. 2011). The cave was large enough that bats could easily have roosted in separate locations with no contact between individuals. Spotted bats at this location were found both through trapping at the mouth of the cave and as mummified spotted bat remains found in cracks within the cave. In Colorado, O’Shea et al. (2011) counted up to 18 spotted bats emerging from long vertical crevices at two maternity roosts. In Arizona, Chambers et al. (2011) had no radio-tagged spotted bats that shared a roost, although roosts were in relatively close proximity (<500 m apart in one area and <2 km apart in another). Cliffs with south-facing aspects capture more heat and thus may provide a warmer microclimate for pups while the female is away from the roost at night. Roosts during the breeding season from northern Arizona were characterized as being located in the upper quarter of tall, vertical sandstone or limestone cliffs ranging in height from 130–850 m and were located at elevations of 1480–1850 m (Chambers et al. 2011). Roosts appeared to be in cracks or crevices. Roosts for females faced south; most (67%) were oriented southwest. The Potential distribution of spotted bats in Colorado. The orientation of male roosts did not differ from random. map was generated using landscape-scale coefficients and known locations in MaxEnt to model predictive probability of occurrence surfaces. Contrary to earlier studies, spotted bats from northern Arizona (Chambers et al. 2011) moved distances from point of capture to roost site ranging from 2.3– 36.3 km. Mean distance from roost to the nearest perennial water source was 5.8 km (range 0.4–18 km). Monitored bats used 1.4 ± 0.1 roosts over 10 ± 2 days. Most reproductive females did not change roosts during the study, but two females that did change roosts moved substantial distances (14 km - lactating female and 30 km - nonreproductive female). Spotted bats in northern Arizona appear to leave summer roosts shortly after civil twilight. Bats left their roosts quickly, and flew up side canyons that ascend into valleys (an elevation gain of several hundred meters), with apparently multiple spotted bats using similar commuting routes (based on acoustic monitoring). Spotted bats appeared to be actively foraging in these higher elevation habitats until approximately midnight. Chambers et al. (2011) found bats did not return to day roosts until approximately 2 hours–30 min before civil twilight for sunrise. As

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they returned to day roosts, they traveled rapidly. Estimated flight speeds for 3 bats were 30 km/h (pregnant female), 42 km/h (nonreproductive male), and 53 km/h (nonreproductive male).

Spotted bats feed primarily on flying moths. Prey species of spotted bats in northern Arizona appear to be primarily composed of three moth families: Geometridae, Noctuidae and Lasiocampidae (Painter et al. 2009). Spotted bats are high-flying bats that emit a low frequency, generally audible echolocation call. When foraging, spotted bats exhibit high site fidelity and typically travel on regular circuits in long, progressive ellipses, but may adopt less predictable feeding patterns and cover larger areas. They use a variety of elevations and vegetation types, including open woodland, shrubland, marsh, forest meadow, desert wash, and open canyon corridor, for foraging and commuting, but key habitat requirements appear to be suitable roosting cliffs and proximity to open foraging areas. Foraging has been observed in forest openings, pinyon-juniper woodlands, large riverine/riparian habitats, riparian habitat associated with small to midsized streams in narrow canyons, wetlands, meadows, and old agricultural fields. Estimates of flying height during foraging in one study averaged 20 m and ranged from 3–50 m (Rodhouse et al. 2005). In areas where the species has been more easily captured in mist-nets, topography and limited open water may force spotted bats to fly at lower heights or in more discrete flight paths, making them more susceptible to capture.

The wintering habits and habitats of the spotted bat are not well understood. Limited reports may indicate the use of caves or buildings in urban environments near cliffs (Sherwin and Gannon 2005). In the northern part of its range, specimens taken in September and October may indicate post-breeding wandering or represent elevation movement towards winter range. Parturition probably occurs prior to mid-June. Postpartum females have been captured from June–late August.

Desiccated spotted bat mummies collected in northern Arizona show that this species has been using the area for a long time (Mead and Mikesic 2001). Mummies sampled ranged in age from <50 years before present to one sample at 9,180 years before present. Recent genetic work indicates that Mexico was likely the origin of the species. The species appeared to move north with warming weather and eventually reached Canada. Currently, the species is most genetically diverse in the Southwest with 20 or more haplotypes, and the population in the Pacific Northwest is dissimilar with 1 haplotype (C. Chambers, pers. comm.).

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G4 S2 Tier 1 - SS SS - *See text on the first page of this section for an explanation of listing categories.

THREATS

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but impoundment of reservoirs and a recent increase in recreational rock climbing may impact the species in localized situations. Pesticide programs for control of moths (agricultural pests) could impact the spotted bat by reducing availability of prey. Loss of foraging habitat (conversion of desert wash vegetation and/or overgrazing of meadows) may also impact the insect prey for the species.

GAPS IN KNOWLEDGE

More information is needed on life history and distribution. Knowledge regarding spotted bat roosting ecology, particularly with respect to winter roosts, and seasonal movement patterns is lacking in Colorado, and throughout the species range. In addition, improved data related to abundance of the species or its local populations would be beneficial for informing management efforts and status determination.

LITERATURE CITED Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of Colorado. Denver, Colorado. Berna, H. J. 1990. Seven bat species from the Kaibab Plateau, Arizona with a new record of Euderma maculatum. Southwestern Naturalist 35:354-356. Chambers, C. L., M. J. Herder, K. Yasuda, D. G. Mikesic, S. M. Dewhurst, W. M. Masters, and D. Vleck. 2011. Roosts and home ranges of spotted bats (Euderma maculatum) in northern Arizona. Canadian Journal of Zoology 89: 1256–1267. Gitzen, R.A., S. D. West, and J. A. Baumgardt. 2001. A Record of the Spotted Bat (Euderma maculatum) from Crescent Bar, Washington. Northwestern Naturalist 82(1):28-30. Hoffmeister, D. F. 1986. The mammals of Arizona. University of Arizona Press, Tucson. 602 pp. Leonard, M. L., and M. B. Fenton. 1983. Habitat use by spotted bats (Euderma maculatum, Chiroptera: Vespertilionidae): roosting and foraging behavior. Canadian Journal of Zoology 61:1487-1491. Mead, J. I., and D. G. Mikesic. 2001. First fossil record of Euderma maculatum (Chiroptera: Vespertilionidae), eastern Grand Canyon, Arizona. The Southwestern Naturalist 46:380-383. Navo, K. W., J. A. Gore, and G. T. Skiba. 1992. Observations on the spotted bat, Euderma maculatum, in northwestern Colorado. Journal of Mammalogy 73:547-551. O’Shea, T. J., Cryan, P. M., Snider, E. A., Valdez, E. W., Ellison, L. E., and Neubaum, D. J. 2011. Bats of Mesa Verde National park, Colorado: composition, reproduction, and roosting habits. Monographs of Western North American Naturalist 5(1):1–19. Painter, M. L., C. L. Chambers, M. Siders, R. R. Doucett, J. O. Whitaker, Jr., and D. L. Phillips. 2009. Diet of spotted bats (Euderma maculatum) in Arizona as indicated by fecal analysis and stable isotopes. Canadian Journal of Zoology 87:865-875. Pierson, E. D. and W. E. Rainey. 1998. Distribution of the spotted bat, Euderma maculatum, in California. Journal of Mammalogy 79:1296-1305.

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Rabe, M. J., M. S. Siders, C. R. Miller and T. K. Snow. 1998. Long foraging distance for a spotted bat (Euderma maculatum) in northern Arizona. The Southwestern Naturalist 43(2):266-269. Rodhouse, T. J., M. F. McCaffrey, and R. G. Wright. 2005. Distribution, foraging behavior, and capture results of the spotted bat (Euderma maculatum) in central Oregon. Western North American Naturalist 65(2):215–222. Schmidly, D. J. 1991. The Bats of Texas. Texas A&M University Press, College Station. 188 pp. Sherwin, R. E. and W. L. Gannon. 2005. Documentation of an urban winter roost of the spotted bat (Euderma maculatum). The Southwestern Naturalist 50(3):402-407. WaiPing, V., and M. B. Fenton. 1989. Ecology of spotted bat (Euderma maculatum) roosting and foraging behavior. Journal of Mammalogy 70:617622. Walker, F. M., J. T. Foster, K. P. Drees, and C. L. Chambers. 2014. Spotted bat (Euderma maculatum) microsatellite discovery using illumina sequencing. Conservation Genetics Resources 6(2):457-459. Watkins, L. C. 1977. Euderma maculatum. Mammalian Species 77:14. Woodsworth, G. C., G. P. Bell, and M. B. Fenton. 1981. Observations of the echolocation, feeding behavior, and habitat use of Euderma maculatum (Chiroptera: Vespertilionidae) in Southcentral British Columbia. Canadian Journal of Zoology 59:1099-1102.

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TRI-COLORED BAT (PERIMYOTIS SUBFLAVUS)

Prepared by Cheri A. Jones and Michael B. Wunder Updated by Christine Avena (2017)

DESCRIPTION

Formerly known as the eastern pipistrelle (Pipistrellus subflavus), the tri-colored bat (Perimyotis subflavus) is one of the smallest North American bats. The bat has distinctly tri- colored dorsal hairs, yellowish-brown or yellowish-gray on dorsum with a paler belly. It has rounded ears with a straight, slender tragus. Its flight pattern is slow and erratic, or moth- like.

Measurements as presented by Armstrong et al. (2011) are as follows: total length 70–90 mm; length of tail 32–42 mm; Tri-colored bat. Photo by E. Wostl length of hindfoot 8–11 mm; length of ear 123–14 mm; length of forearm 30–35 mm; wingspan 21–26 cm; weight 4.5–8.0 g.

DISTRIBUTION

The tri-colored bat has a large range, north from Canada, through Wisconsin, Michigan, and Maine, west into eastern Colorado, south through Oklahoma, northeastern New Mexico and eastern Central America to northeastern Honduras. It is a common species in the woodlands of the eastern U.S., but remains rare west of the Mississippi. Data from Texas, South Dakota, Nebraska, New Mexico and Colorado suggest that the distribution of P. subflavus may be spreading westward. There have been a handful of sightings of both roosting and foraging tri-colored bats in Weld, Boulder, Arapahoe, Larimer, Chaffee, Baca and Pueblo counties, but data on their ecology in Colorado is scarce. Individuals found in the spring and fall in both Colorado (Wostl et al. 2009) and New Mexico suggests that some individuals may be residents, rather than transients, along the western edge of the Great Plains. Records of reproductive females and juveniles suggest this species is an uncommon resident in Colorado. Some overlap of this species with its western counterpart, the canyon bat (Parastrellus hesperus) may occur in the canyonlands of the southeastern part of the state but most records are separated by the central mountains.

NATURAL HISTORY

The tri-colored bat may be a solitary rooster in summer, but also forms maternity colonies of up to 30 individuals. Roost switching has been reported for colonies in Indiana. Tri-colored bats emerge relatively early in the evening to forage, usually above waterways and open clearings. Research from eastern states suggests that females, particularly those pregnant and lactating, may roost in trees (oak and pine, cliffs and buildings to a lesser extent. Males may occasionally roost in trees as well. In Colorado, tri-

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colored bats have been found in woodlands and pastures, often associated with urban settings. Most records for this species in the state have been collected for individuals found at buildings. The tri- colored bat’s diet consists of 6 insect orders: Homoptera, Coleoptera, Diptera, Lepidoptera, Hemiptera, and Hymenoptera. Studies have shown that they eat leafhoppers, planthoppers, ground beetles, scarab beetles, midges, crane flies, winter crane flies, ichneumons, ants, and seed bugs. The female’s diet may consist mainly of Homoptera species while the male’s main food source is often Diptera species.

Tri-colored bats mate between August and October. This is the only time males and females are found together. The female will store the sperm throughout hibernation. Potential distribution of tri-colored bat in Colorado. Fertilization occurs in the spring after hibernation, during The map was generated using landscape-scale coefficients and known locations in MaxEnt to model the months of April and May; at this time, female tri-colored predictive probability of occurrence surfaces. bats leave their hibernacula to form summer colonies a short distance from the hibernaculum. Females then give birth in late May through early July depending on where they live. They have a gestation period of about 44 days and usually give birth to 2 young. Young are born blind and hairless but are able to fly after 3 weeks. While new research suggests that some individuals, particularly males, may make a latitudinal migration south for the winter, many of the bats remain in their local habitat to hibernate. Hibernacula (mostly caves and rock crevices, but also highway culverts, mines, and forested areas) can contain thousands of bats in the eastern part of its range, roosting singly or in small groups within a single hibernacula. Records from populations in Nebraska and Texas suggest smaller numbers of individuals in western hibernacula, around 30 or so. Hibernation is marked by very deep torpor relative to other bats, and individuals might be covered by condensation. Individuals are known (from a record of a banded bat in Illinois) to live at least 14.8 years in the wild.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G2G3 S2 - - - - Petitioned *See text on the first page of this section for an explanation of listing categories.

THREATS

White-nose syndrome (WNS) and wind turbine mortality are known specific threats to this species. Populations of this bat in the eastern part of its range are known to be severely affected by WNS during hibernation, with losses of more than 80% reported in some hibernacula leading to a petition for listing and 90-day finding considered warranted by the USFWS in 2017. There is limited evidence that some colonies of P. subflavus may show some resistance and tolerance to infection by Pseudogymnoascus destructans, the causative agent of WNS. Habitat fragmentation may also be a threat to this species,

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particularly as populations are impacted by disease and wind turbine construction. Non-specifically, individuals can be vulnerable at roosts. Exclusion from anthropogenic structures may also be a threat if done improperly.

GAPS IN KNOWLEDGE

Many aspects of diet, reproduction, and other ecology remain poorly understood for this species, especially in western parts of it’s the range. Roosting ecology outside of urban areas is largely unknown for this species in Colorado. The long-term impacts of WNS on the North American population remain unclear. This species may be expanding its range in Colorado but movements are largely unknown in the state.

LITERATURE CITED Armstrong, D. M., Adams, R. A. and Taylor, K. E., 2006. New records of the eastern pipistrelle (Pipistrellus subflavus) in Colorado. Western North American Naturalist 66(2):18. Armstrong, D. M. J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of Colorado. Denver, Colorado. Davis, W. B., and D. J. Schmidly. 1994. The Mammals of Texas. Texas Parks and Wildlife, Austin. Farrow, L. J., and Broders, H. G. 2011. Loss of forest cover impacts the distribution of the forest-dwelling tri-colored bat (Perimyotis subflavus). Mammalian Biology, 76(2):172-179. Fitzgerald, J. P., C. A. Meaney, and D. M. Armstrong. 1994. Mammals of Colorado. Denver Museum of Natural History and University Press of Colorado, Niwot. Fitzgerald, J. P., D. Taylor, and M. Prendergast. 1989. New records of bats from northeastern Colorado. Journal of the Colorado-Wyoming Academy of Science 21:22. Fraser, E. E., McGuire, L. P., Eger, J. L., Longstaffe, F. J., and Fenton, M. B. 2012. Evidence of latitudinal migration in tri-colored bats, Perimyotis subflavus. PLoS One 7(2) p.e31419. Frick, W. F., Cheng, T. L., Langwig, K. E., Hoyt, J. R., Janicki, A. F., Parise, K. L., Foster, J. T., and Kilpatrick, A. M. 2017. Pathogen dynamics during invasion and establishment of white‐nose syndrome explain mechanisms of host persistence. Ecology 98(3):624-631. Fujita, M. S., and T. H. Kunz. 1984. Pipistrellus subflavus. Mammalian Species 228:1-6. Kunz, T. H. 1999. Eastern pipistrelle Pipistrellus subflavus. Pp. 114-115, in The Smithsonian Book of North American Mammals (D. E. Wilson and S. Ruff, eds.). Smithsonian Institution Press, Washington, D.C. Menzel, M. A., L. T. Lepardo, and J. Laerm. 1996. Possible use of a basal cavity as a maternity roost by the eastern pipistrelle Pipistrellus subflavus. Bat Research News 37:115-116. Menzel Jr., J. A., J. M. Menzel, T. C. Carter, J. O. Whitaker, and W. M. Ford. 2002. Notes on the late summer diet of male and female eastern pipistrelles (Pipistrellus subflavus) at Fort Mountain State Park, Georgia. Georgia Journal of Science. 60:170-179.

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Perry, R. W., and R. E. Thill. 2007. Tree roosting by male and female eastern pipistrelles in a forested landscape. Journal of Mammalogy 88(4):974-981. Valdez, E. W., K. Geluso, J. Foote, G. Allison-Kosior, and D. M. Roemer. 2009. Spring and winter records of the eastern pipistrelle (Perimyotis subflavus) in southeastern New Mexico. Western North American Naturalist 69(3):396-398. Veilleux, J. P., J. O. Whitaker Jr., and S. L. Veilleux. 2003. Tree-roosting ecology of reproductive female eastern pipistrelles, Pipistrellus subflavus, in Indiana. Journal of Mammalogy 84(3):1068-1075. Whitaker, J. O., Jr. 1998. Life history and roost switching in six summer colonies of eastern pipistrelles in buildings. Journal of Mammalogy 79:651-659. Wostl, E., K. Navo, and N. LaMantia-Olson. 2009. Additional observations of the eastern pipistrelle (Perimyotis subflavus) in Colorado. Bat Research News 50(3).

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TOWNSEND’S BIG-EARED BAT (CORYNORHINUS TOWNSENDII)

Prepared by Richard Sherwin Updated by Antoinette J. Piaggio and Kirk W. Navo (2017)

DESCRIPTION

The Townsend’s big-eared bat (Corynorhinus townsendii), a member of the family Vespertilionidae, can be distinguished from all other vespertilionids by the presence of prominent, bilateral nose lumps and very large ears (30–38mm). It also has a well developed tragus. It is a medium sized bat with a brown to grayish brown coloration.

The measurements of the Townsend’s big-eared bat as reported by Armstrong at el. (2011) are: total length of 90– Townsend’s big-eared bat. Photo by D. 112 mm; length of tail 35–54 mm; length of forearm 39–48 Neubaum mm; wingspan of 30–34 mm; weight of 9–14g.

DISTRIBUTION

The Townsend’s big-eared bat occurs throughout the West, and is distributed from the southern portion of British Columbia south along the Pacific coast to central Mexico (C. t. pallenescens, C. t. mexicanus, and C. t. townsendii) and east into the Great Plains (C. t. ingens; endangered), with isolated populations occurring in the southeastern and eastern U.S. (C. t. virginianus; endangered). It has been reported in a wide variety of habitat types ranging from sea level–3300 m. Habitat associations include: coniferous forests, mixed mesophytic forests, deserts, native prairies, riparian communities, active agricultural areas, and coastal habitat types.

NATURAL HISTORY

Distribution is strongly correlated with the availability of caves and cave-like roosting habitat, with population centers occurring in areas dominated by exposed, cavity forming rock and/or historic mining districts. Its habit of roosting on open surfaces makes it readily detectable, and it is often the species most frequently observed (commonly in low numbers) in caves and abandoned mines throughout its range. In Colorado, it is the most frequently encountered species found using abandoned mines and caves. Unlike other vepertilionids, C. townsendii does not utilize small cracks within roosting sites, preferring to hang in the open, which may lead to increased disturbance by humans. It has also been reported to utilize buildings, bridges, rock crevices and hollow trees as roost sites. Summer maternity colonies range in size from a few dozen to several hundred individuals. In Colorado, only a few maternity colonies with more than 500 estimated bats have been documented to date. Maternity colonies form between March and June (based on local climactic factors), with a single pup born between May and July. Maternity colonies may use multiple roosts in an area throughout the season. Males remain

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solitary during the maternity period. Winter hibernating colonies are composed of mixed-sexed groups that can range in size from a single individual to colonies of several hundred animals (or in some areas, particularly in the eastern U.S., several thousand). Studies in Colorado have provided some insights into winter roost selection by this species (Hayes et al. 2011). In Colorado, only 2 caves have been documented with numbers >90 (90–600), and only 2 mines with 90–200 hibernating bats. Seasonal movement patterns are not well understood, although there is some Potential distribution of Townsend’s big-eared bat in Colorado. The map was generated using landscape- indication of local migration, perhaps along an altitudinal scale coefficients and known locations in MaxEnt to model predictive probability of occurrence surfaces. gradient. Individuals PIT tagged at a summer maternity colony in an abandoned mine were found hibernating in a cave 48 km away in Colorado (D. Neubaum, unpublished data). Roosting sites may be used as both maternity roosts, hibernacula, and day/night roosts. In some cases, individuals may aggregate at certain caves or mines as a transient roost or swarming site (Ingersoll et al. 2010). Since C. townsendii may utilize multiple hibernacula in a single winter, it is difficult to get accurate population estimates in a single survey. It is inferred that this species remains semi-active during the winter. Mating generally takes place between October and February in both migratory sites and hibernacula. Foraging associations include edge habitats along streams, adjacent to and within a variety of wooded habitats. This species often travels large distances while foraging, including movements <10 miles during a single evening. C. townsendii is a moth specialist with over 90% of its diet composed of members of the Order Lepidoptera.

The relatedness of Townsend’s big-eared bats in a single colony is fairly high. Males tend to have higher genetic diversity than the females because they are not as sedentary. Microsatellite data revealed high male gene flow in the bats and low female gene flow. Data shows that all variation among groups of bats is relative to male influence on gene flow, regardless of population grouping (Piaggio et al. 2009).

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G4 S2 Tier 1 SC SS SS - *See text on the first page of this section for an explanation of listing categories.

THREATS

The primary threat to Townsend’s big-eared bat is almost certainly disturbance or destruction of roost sites (e.g., recreational caving and mine exploration, mine reclamation, renewed mining in historic districts, etc.). Surveys conducted in Oregon and California indicate that historic roost sites have been negatively impacted in recent years, with most reported colonies exhibiting moderate to sizable reduction in numbers. Additional surveys in Utah indicate that several historic maternity sites have been

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abandoned, although it is not known if these colonies have relocated. To date in Colorado, no major impacts have been documented to known colonies of this species. This species can be sensitive to disturbance and has been documented to abandon roost sites after human visitation. In California and at a number of sites in the East, depressed populations have recovered with the protection (i.e., gating) of roosts. In large portions of its western range, dependence upon abandoned mines puts this species at risk if mine reclamation and renewed mining projects do not mitigate for roost loss, or do not conduct adequate biological surveys prior to mine closure. The Bats/Inactive Mines Project of CPW (1990–2010) conducted over 5,600 mine surveys, and resulted in >800 bat gates installed at abandoned mines scheduled for closure. The vast majority of these gated mines have been to conserve roost sites for Townsend’s big-eared bats. Mine closures in the state continue to be a conservation concern for this species. Both roosting and foraging habitat may be impacted by timber harvest practices. Pesticide spraying in forested and agricultural areas may affect the prey base. Because of its use of multiple roosting sites and low population density, accurate population counts are difficult to make and have resulted in very few long term surveys of their populations.

GAPS IN KNOWLEDGE

Identification and protection of significant roost sites is still needed in most areas. Significant populations need to be monitored over time. More information is needed on foraging requirements, seasonal movement patterns, and population genetics (i.e., the degree of relatedness within and between different maternity roosts). The effects of white-nose syndrome, a disease caused by the pathogenic fungus Pseudogymnoascus destructans (Pd), on this species should be investigated. While it appears that Pd does not cause disease in the eastern subspecies of Townsend’s big-eared bat, it is unknown if this holds for the other subspecies.

LITERATURE CITED Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of Colorado. Denver, Colorado. Brown, P. E., R. Berry, and C. Brown. 1994. Foraging behavior of Townsend's big-eared bats (Plecotus townsendii) on Santa Cruz Island. Fourth California Islands Symposium: Update on the Status of Resources, 367-369. Clark, B. K., and B. S. Clark. 1997. Seasonal variation in use of caves by the endangered Ozark big-eared bat (Corynorhinus townsendii ingens) in Oklahoma. American Midland Naturalist 137:388-392. Hayes, M. A., R. A. Schorr, and K. W. Navo. 2011. Hibernacula selection by Townsend's big-eared bat in southwestern Colorado. Journal of Wildlife Management 75(1):137–143. Ingersoll, T. E., K. W. Navo, and P. De Valpine. 2010. Microclimate preferences during swarming and hibernation in the Townsend's big-eared bat, Corynorhinus townsendii. Journal of Mammalogy 91:1242-1250. Kunz, T. H., and R. A. Martin. 1982. Plecotus townsendii. Mammalian Species 175:1-6.

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Piaggio, A. J., and S. L. Perkins. 2005. Molecular phylogeny of North American long-eared bats (Vespertilionidae: Corynorhinus); inter-and intraspecific relationships inferred from mitochondrial and nuclear DNA. Molecular Phylogenetics and Evolution 37: 762-775. Piaggio, A. J., K. W. Navo, and C. W. Stihler. 2009. Intraspecific comparison of population structure, genetic diversity, and dispersal among three subspecies of Townsend's big-eared bats, Corynorhinus townsendii townsendii, C. t. pallescens, and the endangered C. t. virginianus. Conservation Genetics 10:143-159. Pierson, E.D., and W.E. Rainey. 1996. The distribution, status and management of Townsend's big-eared bat (Corynorhinus townsendii) in California. California Department of Fish and Game, Bird and Mammal Conservation Program Rep. 96-7. 49 pp. Pierson, E. D., M. C. Wackenhut, J. S. Altenbach, P. Bradley, P. Call, D. L. Genter, C. E. Hariis, B. L. Keller, B. Lengus, L. Lewis, B. Luce, K. W. Navo, J. M. Perkins, S. Smith, and L. Welch. 1999. Species conservation assessment and strategy for Townsend's big-eared bat (Corynorhinus townsendii townsendii and Corynorhinus townsendii pallescens). Idaho Conservation Effort, Idaho Department of Fish and Game, Boise, Idaho. 68 pp. Sherwin, R. E., D. Stricklan, and D. S. Rogers. 2000. Roosting affinities of Townsend's Big-eared Bat (Corynorhinus townsendii) in northern Utah. Journal of Mammalogy 81:939-947. USFWS (US Fish and Widllife Service). 2008. Ozark big-eared bat (Corynorhinus townsendii ingens) 5-year review: summary and evaluation. USFWS, Oklahoma Ecological Services Field Office, Tulsa, OK. USFWS (US Fish and Widllife Service). 2008. Virginia big-eared bat (Corynorhinus townsendii virginianus) 5-year review: summary and evaluation. Report prepared by West Virginia Field Office. 21 pp. USFWS (US Fish and Widllife Service). 2009. Virginia big-eared bat (Corynorhinus townsendii virginianus) plan for controlled holding, propagation, and reintroduction. USFWS, West Virginia Field Office, Elkins, West Virginia.

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WESTERN SMALL-FOOTED MYOTIS (MYOTIS CILIOLABRUM)

Prepared by Milu Velardi and Daniel J. Neubaum (2017)

DESCRIPTION

The western small-footed myotis (Myotis ciliolabrum), previously identified as Myotis leibii, is a small bat with a keeled calcar, small feet, black ears, and a black mask across the eyes and nose. This species closely resembles the California myotis (Myotis californicus). The color of this bat may vary geographically in Colorado, with species in the eastern parts of the state (subspecies M. c. ciliolabrum) appearing more pale than individuals in the west (subspecies

M. c. melanorhinus). Those found in western Colorado may Western small-footed myotis. Photo by have a reddish-brown hue, with some individuals found in D. Neubaum northwest Colorado found to be paler than those found in the Four Corners region (Armstrong 1972). In general, the pelage can have a pronounced sheen due to the burnished tips of the hairs.

The western small-footed bat differs from the California myotis by having a longer, broader, and flatter skull in lateral view. The rostrum has been described as making a broad V shape in comparison to the California myotis, which resembles a narrower U shape. When laid forward, the ears of the western small-footed bat barely extend beyond the muzzle, unlike those of the California myotis. In addition, the tail of the western small-footed bat may extend about 4 mm beyond the posterior border of the

uropotagium, unlike that of the California myotis (Constantine Myotis ciliolabrum vs. M. californicus 1998).

The measurements of the Western small-footed myotis as taken from Armstrong et al. (2011) are: total length 75–88 mm; tail 33–42 mm; hindfoot 5–8 mm; ear 12–16 mm, forearm 30–35 mm; wingspan 21– 25 cm; weight 3.5–5.5 g.

Comparison of measurements Myotis ciliolabrum vs. Myotis californicus: Total length Tail Hindfoot Ear Forearm Wingspan Weight Species (mm) (mm) (mm) (mm) (mm) (cm) (g) M. californicus 70–84 30–40 5.5–8.2 11–15 29–36 22–26 3–5 M. ciliolabrum 75–88 33–42 5–8 12–16 30–35 21–25 3.5–5.5

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DISTRIBUTION

The western-small footed bat is considered a common bat in western North America at elevations below 2650 m, where suitable foraging and roosting habitat is present. It is distributed from South Alberta and Saskatchewan in Canada, south through eastern Colorado and western Kansas (Simmons 2005), to north and central Mexico (Ceballos and Oliva 2005). Records for this bat in Colorado are not uncommon across the West Slope, through the central mountains, and along the Front Range. In the eastern plains of the state, it is less common, and perhaps absent, due to a lack of suitable roosting habitat. Records of the species in eastern Colorado are limited to rocky terrain north of the South Platte River and the canyonlands south of the Arkansas River (Armstrong et al. 1994). This myotis species is most common in arid desert, badlands, and some semiarid habitats. At higher elevations, Potential distribution of western small-footed myotis in it can be found in more mesic habitats in southern portions Colorado. The map was generated using landscape- of its range (Holloway and Barclay 2001). It has also been scale coefficients and known locations in MaxEnt to model predictive probability of occurrence surfaces. found at a range of elevations, with hibernation observed as high as 2970 m (Armstrong et al. 1994). Nomenclature of this species has been complicated. In 1984, Van Zyll de Jong recognized two distinct species: Myotis leibii (eastern small-footed myotis) and Myotis ciliolabrum (western small-footed myotis). Previously, the two species were considered under Myotis leibii. In Colorado, at present there are two subspecies identified: M. C. melanorhinus in the San Luis Valley and western Colorado and M. c. ciliolabrum in eastern Colorado.

NATURAL HISTORY

The western small-footed myotis occurs in a variety of habitats and is widely distributed across the western U.S. Acoustic work suggests that this species may be more common than mist-net data indicates (Neubaum 2017). It can be found in deserts, chaparral, riparian areas, and coniferous forests but is most common in pinyon-juniper forests. Summer roosts include rock crevices, mines, caves, dwellings, burrows, and under bark. It has also been found beneath rocks on the ground. Surveys at abandoned mines from 1990–2010 in Colorado documented 677 western small-footed myotis—the second most encountered species using mines as roosts. Mine roosts ranged from 1560-3140 m in elevation. Most records are from summer/fall surveys, but 66 winter records have been documented in mines during this project. Foraging takes place low to the ground (1 m or so) with erratic, butterfly-like flying patterns. The western small-footed bat feeds on moths, flies, and spiders, although the diet has not been studied in detail (Armstrong et al. 1994). They are highly agile in flight, and can be seen feeding among rocks, shrubs, trees, and over open areas, arroyos, and forest canopy. This species feeds relatively early in the evening, like other smaller species of bats (e.g., California myotis and canyon bat) found in similar habitats.

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The western small-footed myotis mates during the fall, with young born between June and September in Colorado (Adams 2003). Females give birth to one pup, although twins have been recorded. Overwintering locations for the small-footed bat is largely unknown but records have been collected from caves, mines, tunnels, and rock crevices in Colorado (Warren 1942; Armstrong 1972). Hibernacula have been located in areas with freezing temperatures and low humidity—this behavior is atypical for bats as hibernacula with warmer temperatures and higher humidity are most commonly selected by small, insectivorous bat species.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G5 S4 - - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

The overall status of the western small-footed myotis is thought to be secure as of November 2016. However, the species may be affected by closure of abandoned mines without adequate surveys. The removal of large-diameter snags in timber practices may influence day roosting habitat. Some riparian- management practices and large scale water impoundment may be detrimental to local populations. Given its close relatedness to other Myotis species affected by white-nose syndrome, the Western small-footed bat may prove to be highly vulnerable to effects from the disease if it progresses into Colorado.

GAPS IN KNOWLEDGE

More information and research is needed in Colorado regarding this species and the potential impacts from forestry management practices, such as pinyon-juniper treatments and mine closures. General surveys of occurrence along riparian and cliff band stretches of the state’s western slope would be beneficial. North American Bat grids run in this portion of the state could also be reviewed for such presence/absence data. Determining winter roosts of this species is also needed.

LITERATURE CITED Adams, R. A. 2003. Bats of the Rocky Mountain West: Natural history, ecology, and conservation. University Press of Colorado. Boulder, CO. 289 pp. Armstrong, D. M. 1972. Distribution of mammals in Colorado. Monograph of the Museum of Natural History, the University of Kansas 3:1-415. Armstrong, D. M., R. A. Adams, and J. Freeman. 1994. Distribution and ecology of bats in Colorado. Natural History Inventory, Univ. Colorado Mus. 15:1-82. Armstrong, D. M. J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of Colorado. Denver, Colorado.

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Ceballos, G., and G. Oliva. 2005. Los mamiferos silvestres de Mexico. Conabio/Fondo de Cultura Economica, Mexico D.F. Pp. 988. Constantine, D. G. 1998. An overlooked external character to differentiate Myotis californicus and Myotis ciliolabrum (Vespertilionidae). Journal of Mammalogy 79:624-630. Holloway, G. L., and R. M. R. Barclay. 2001. Myotis ciliolabrum. Mammalian Species 670:1-5. Neubaum, D. J. 2017. Bat Composition and Roosting Habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 - 2016. Colorado Parks and Wildlife, Grand Junction, CO. Simmons, N. B. 2005. Order Chiroptera. Pp. 312-529, in Mammal species of the world, a taxonomic and geographic reference, third ed., 2 vols. Johns Hopkins Univ. Press, Baltimore. The IUCN Red List of Threatened Species 2017: e.T14153A22058110. http://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T14153A22058110.en. Accessed March 2018. Van Zyll de Jong, C.G. 1984. Taxonomic relationship of Nearctic small-footed bats of the Myotis leibii group (Chiroptera: Vespertilionidae). Canadian Journal of Zoology 52:2519-2526. Warren, E.R. 1942. The mammals of Colorado, second ed. Univ. Oklahoma Press, Norman, 330 pp.

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YUMA MYOTIS (MYOTIS YUMANENSIS)

Prepared by Michael A. Bogan, Ernest W. Valdez, and Kirk W. Navo Updated by Daniel J. Neubaum (2017)

DESCRIPTION

The Yuma myotis (Myotis yumanensis), a member of the family Vespertilionidae, is a small bat that is usually gray or brown to pale tan dorsally, with a paler venter of tan or gray; ears and membranes are frequently pale brown to gray. In some areas this bat is difficult to distinguish from M. lucifugus and caution is required (Rodhouse et al. 2008). Luszcz et al. (2016) suggest using acoustic comparisons with a minimum call frequency cut-off of 43 kHz. This technique may provide a more reliable method of determining species than external Yuma myotis. Photo by D. Neubaum morphology. In Colorado, forearm measurements with a cut-off of 36 mm generally work.

The measurements of the Yuma myotis as reported by Armstrong et al. (2011) are: total length of 78–90 mm; length of tail 32–37; length of hind foot 7–9; length of ear 12.5–14.0mm; length of forearm 32– 38; wingspan of 22–26 mm; weight of 3.5–5.0 g.

DISTRIBUTION

The Yuma myotis ranges across the western third of North America from British Columbia to Baja California and southern Mexico. In the U.S. it occurs in all the Pacific coastal states, western Montana in the north, and as far east as western Oklahoma in the south. In Colorado, records for the Yuma myotis suggest the species is common across the lower elevations of canyon country on the Western Slope and along river canyons of the southeast counties.

NATURAL HISTORY

This bat is usually associated with permanent sources of water, typically rivers and streams, but Yuma myotis also use tinajas in the arid West. It occurs in a variety of habitats including riparian, arid scrublands and deserts, and forests. Mating is typically in the fall and females give birth to one young. Although records for roosts are limited, the species has been found roosting in bridges, buildings, cliff crevices, caves, mines, abandoned swallow mud nests, and trees (Braun et al. 2015). Maternity colonies in the West form from mid-spring to mid-summer and may range in size from small groups up to several thousand individuals. Males tend to roost singly in the summer. Efforts to identify roosts for this species in Colorado have largely been overlooked. Surveys of Colorado National Monument and the adjacent McInnis Canyons National Conservation Area found maternity colonies of Yuma myotis exclusively in rock crevices of cliff faces situated lower in the canyons where proximity to the Colorado

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River and its associated riparian areas were closest (Neubaum 2017). Emergence counts for some of these roosts numbered up to 200 individuals. Individuals are known to become active and forage just after sunset, feeding primarily on aquatic emergent insects. Their diet includes caddis flies, flies, midges, small moths, and small beetles. After feeding, they periodically rest at night roosts where the food is digested. In Colorado National Monument an automotive tunnel lined with gunite is used

Potential distribution of Yuma myotis in Colorado. The as a night roost by hundreds of reproductive females and map was generated using landscape-scale coefficients young of the year that use day roosts in rock crevices of the and known locations in MaxEnt to model predictive probability of occurrence surfaces. nearby cliff faces (Adams 1990; Neubaum 2016). Siemers (2002) and Navo et al. (2002) noted Yuma myotis using two caves at higher elevations during the fall transition season and suggested these unusually high records may be tied to swarming opportunities documented at those sites. Radiotracking work in southeast Colorado during the fall transition season resulted in roosts found in rock crevices and several anthropogenic structures (E. Schmal, unpublished data). Hibernacula within the state are largely unknown.

STATUS

NatureServe/CNHP SWAP CPW BLM USFS USFWS G5 S3 - - - - - *See text on the first page of this section for an explanation of listing categories.

THREATS

Yuma myotis may be affected by closure of abandoned mines without adequate surveys, some forest management practices, and disturbance of maternity roosts in caves and buildings. Since this species will use anthropogenic structures, it is vulnerable to destructive pest control activities. Some riparian- management practices and large scale water impoundment may be particularly detrimental to local populations of Yuma myotis due to the species preference for roost sites in close proximity to such features. Given its close relatedness to other Myotis affected by white-nose syndrome and recent diagnosis with the disease in Washington, the Yuma myotis may prove to be highly vulnerable to effects from the disease if it progresses into Colorado (Stadelmann et al. 2007).

GAPS IN KNOWLEDGE

More information on use and acceptance of bat gates, impacts of grazing and riparian habitat management, winter range, and winter roost requirements is needed. Information on geographic variation in roosting and foraging requirements would be beneficial. Additional techniques that improve species determination and reduce confusion with similar M. lucifugus would be beneficial. Investigation

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of interspecific competition with similar species such as M. lucifugus and M. volans may help explain the geographic variation of these species.

LITERATURE CITED Adams, R. A. 1990. Bat species abundance and distribution in Colorado National Monument: A two year survey 1989 - 1990. University of Colorado, Boulder, CO. Armstrong, D. M., J. P. Fitzgerald, and C. A. Meaney. 2011. Mammals of Colorado. University Press of Colorado. Denver, Colorado. Arroyo-Cabrales, J. and S. T. Álvarez-Castañeda. 2008. Myotis yumanensis. The IUCN Red List of Threatened Species 2008: e.T14213A4423514. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T14213A4423514.en. Accessed March 2018. Barbour, R. W., and W. H. Davis. 1969. Bats of America. The University Press of Kentucky, 286 pp. Betts, B. J. 1997. Microclimate in Hell's Canyon mines used by maternity colonies of Myotis yumanensis. Journal of Mammalogy 78:1240-1250. Braun, J. K., B. Yang, S. B. Gonzalez-Perez, and M. A. Mares. 2015. Myotis yumanensis (Chiroptera: Vespertilionidae). Mammalian Species 47:1-14. Brigham, R. M., H. D. Aldridge, and R. L. Mackey. 1992. Variation in habitat use and prey selection by Yuma bats, Myotis yumanensis. Journal of Mammalogy 73:640-645. Harris, A. H. 1974. Myotis yumanensis in interior southwestern North America, with comments on Myotis lucifugus. Journal of Mammalogy 55:589-607. Hoffmeister, D. F. 1986. Mammals of Arizona. University of Arizona Press and Arizona Game and Fish Department, Tucson. 602 pp. Luszcz, T. M. J., J. M. K. Rip, K. J. Patriquin, L. M. Hollis, J. M. Wilson, H. D. M. Clarke, J. Zinck, and R. M. R. Barclay. 2016. A blind-test comparison of the reliability of using external morphology and echolocation-call structure to differentiate between the Little Brown Bat (Myotis lucifugus) and Yuma Myotis (Myotis yumanensis). Northwestern Naturalist: A Journal of Vertebrate Biology 97:13- 23. Navo, K. W., S. G. Henry, and T. E. Ingersoll. 2002. Observations of swarming by bats and band recoveries in Colorado. Western North American Naturalist 62:124-126. Neubaum, D. J. 2017. Bat composition and roosting habits of Colorado National Monument & McInnis Canyons National Conservation Area: 2014 - 2016. Colorado Parks and Wildlife, Grand Junction, CO. Pierson, E. D., W. E. Rainey, and R. M. Miller. 1996. Night roost sampling: a window on the forest bat community in northern California. Pp. 151-163 in Bats and Forest Symposium, (R. M. R. Barclay and M. R. Brigham, eds.), October 19-21, 1995, Victoria, British Columbia. Research Branch, B. C. Ministry of Forests, Victoria. Working Paper 23/1996.

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Rodhouse, T. J., S. A. Scott, P. C. Ormsbee, and J. M. Zinck. 2008. Field identification of Myotis yumanensis and myotis lucifugus: a morphological evaluation. Western North American Naturalist 68:437-443. Siemers, J. L. 2002. A survey of Colorado's caves for bats. Colorado Natural Heritage Program, Fort Collins, CO. Stadelmann, B., L. K. Lin, T. H. Kunz, and M. Ruedi. 2007. Molecular phylogeny of New World Myotis (Chiroptera, Vespertilionidae) inferred from mitochondrial and nuclear DNA genes. Molecular Phylogenetics and Evolution 43:32–48

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