Bat Species Presence in Southwestern Montana

Scientific Disciplines
Biological Sciences - Terrestrial
Volume 17, No. 1-4

Bat species presence in southwestern montana 
Sarah LaMarr, USDI Bureau of Land Management, Butte Field Office, Butte, Montana 59701
Amy J. Kuenzi, Department of Biological Sciences, Montana Tech, Butte, Montana 59701
Published information on bat species presence in many parts of Montana is limited. Our study 
was initiated to gather data on the distribution of bat species found in the southwestern part of 
the state. We captured 106 individuals of eight bat species in mist-nets at 15 water sources in 
southwestern Montana during July through August 2003-2006. The western long-eared myotis 
(Myotis evotis) was the most frequently captured species and detected at over half the sites 
surveyed. Other common species captured across numerous sites included little brown myotis 
(M. lucifugus), hoary bats (Lasiurus cinereus), and big brown bats (Eptesicus fuscus). These 
species are apparently broadly distributed throughout southwestern Montana, occurring in a 
variety of habitat types. Our study provides some much needed baseline data on bat distribution 
in southwestern Montana.
Key Words: bats, Chiroptera, distribution, Montana 
the Public Health Service for rabies work 
Bats are important components of 
in the late 1950s through the 1960s. The 
terrestrial ecosystems (Fenton 1997). They 
majority of these collected bats came from 
have low reproductive rates for mammals 
Missoula and Ravalli counties in western 
their size (Hill and Smith 1984), which 
Montana. The work of Jones et al. (1973), 
makes their populations slow to recover 
Lampe et al. (1974), and Shryer and Flath 
from high levels of mortality. Thus, potential 
(1980) added information on bats present 
for factors such as habitat alteration, 
in Carbon County in southeastern Montana. 
environmental change, and more recently 
Swenson and Bent (1977) provided a list of 
white nose syndrome (Blehert et al. 2009) 
species present in Yellowstone County in 
to cause declines in bat abundance has led 
south-central Montana while Swenson and 
to a focus on bats by many natural resource 
Shanks (1979) documented bats at three 
agencies. However, data necessary to 
sites in northeastern Montana. Most recently 
develop effective conservation plans for bat 
Hendricks et al. (2000) documented species 
species are often lacking. Even such basic 
present in the Little Rocky Mountains of the 
information as species distribution is not 
north-central part of the state.  Published 
available for many locations (Saugey 1991, 
data on presence of bat species in other 
Pierson 1998).  
parts of Montana is still limited. Our study 
In Montana, published records on bat 
was initiated to gather preliminary data on 
species distribution and abundance are 
the distribution of bat species found in the 
limited and cover only parts of the state. 
southwestern part of the state. 
Nicholson (1950) provided the first record of 
a spotted bat (Euderma maculatum) found 
Tudy area
in a home in Billings. Swenson (1970) 
This study was conducted in 
published data on distribution of the western 
southwestern Montana on USDI Bureau 
small-footed myotis (Myotis ciliolabrum
of Land Management (BLM) holdings of 
in eastern Montana. Hoffman et al. (1969) 
the Butte Field Office. These holdings are 
made the first attempt to summarize 
located in Jefferson, Broadwater, Lewis 
distribution of numerous bat species in 
and Clark, and Silver Bow Counties. Bats 
the state based on specimens collected by 
were surveyed at 15 different sites located 

across these holdings. Sites were selected 
bats based upon the degree of epiphyseal-
based on their accessibility and the presence 
diaphyseal fusion of wing bones (Anthony 
of permanent water sources.  Elevations at 
1988). We identified species based on 
these sites ranged from ~ 1300 m to 2100 m.  
published keys and species accounts (van 
To examine patterns of distribution 
Zyll de Jong 1985, Adams 2003, Nagorsen 
by different bat species, we classified each 
and Brigham 1993). Western long-eared 
survey site into 4 habitat types: S = water 
myotis (M. evotis) and fringed myotis  
sources surrounded by sagebrush (Artemisia 
(M. thysanodes) were distinguished from 
spp.), D = water sources surrounded by 
one another by ear length (van Zyll de Jong 
Douglas- fir (Pseudotsuga menziesii), 
1985).  Specifically, the western long-
C= streams lined with large deciduous 
eared myotis has an overall ear length that 
trees such as cottonwood (Populus spp.), 
exceeds 50 percent of the forearm length 
or quaking aspen (Populus tremuloides), 
and when the ear on the western long-eared 
W = streams lined with riparian shrubs 
myotis is pressed forward it extends ≥10 
(predominately Salix spp.).
mm beyond the tip of the nose (van Zyll de 
Jong 1985). All captured bats were released 
after handling. Handling procedures were 
This study was conducted during mid 
approved by Montana Fish,Wildlife, and 
July-early August, 2003-2006. At each site, 
we captured bats using 36-mm mesh, 50 
denier, 2.1-m x 5.4-m mist-nets placed in 
locations considered to be suitable flyways 
We identified a total of 106 individuals 
for bats, such as open pools of water or 
of eight species from 15 water sources in 22 
clearings in stands of trees. The number of 
trap nights from southwestern Montana (Table 
nets used per site varied but ranged from 
1). Survey effort varied by site. The majority 
two to four. Nets were opened ~ 1 hr before 
of sites were only surveyed once but several 
sunset and kept open for 3-5 hrs depending 
sites were surveyed twice and one site was 
on activity. Captured bats were identified 
surveyed five times (Appendix A).  
to species and data on body measurements, 
Western long-eared myotis and fringed 
sex, reproductive condition of females, 
myotis were the most abundant species 
and age (juvenile vs. adult) were recorded. 
captured, each made up over 20 percent of 
We assessed reproductive condition by 
total captures. The western long-eared myotis 
examination of the lower abdomen and 
was the most broadly distributed species 
mammary glands (Racey 1988). We aged 
within the study region (Tables 1 and 2). This 
Table 1.  Number of bats captured by species from Southwestern Montana, July-August, 
  bat species 
Number captured  percentage of  percentage
Total Captures  of Sites
No. Females) 
Western Smal -footed Myotis (Myotis ciliolabrum)  
6 (5, 1) 
Western Long-eared Myotis (M. evotis)  
23 (17, 6) 
Little Brown Myotis (M. lucifugus
13 (10,3) 
Fringed Myotis (M. thysanodes
22 (22,0) 
Long-legged Myotis (M. volans
12 (4, 8) 
Hoary Bat (Lasiurus cinereus
13 (10, 3) 
Silver-haired Bat (Lasionycteris noctivagans
7 (6, 1)  
Big Brown Bat (Eptesicus fuscus
10 (8, 2)  
106 (82, 24)  
Bat Species Presence in Southwestern Montana       15

Table 2.  Occurrence of bat species by locality (see Appendix 1) and habitat type  (S = water 
sources surrounded by sagebrush (Artemisia spp.), D = water sources surrounded by Douglas- 
fir (Pseudotsuga menziesii), C= streams lined with large deciduous trees such as cottonwood 
 spp.), or quaking aspen (Populus tremuloides), W = streams lined with riparian 
shrubs (predominately Salix spp.) for each species in southwestern Montana , July-August 
2003 - 2006. 
Bat Species 
Localities (appendix 1)  habitat Type
  Western Smal -footed Myotis (Myotis ciliolabrum
S, D, C
  Western Long-eared Myotis (M. evotis
W, S, D, C
  Little Brown Myotis (M. lucifugus
W, S, D
  Fringed Myotis (M. thysanodes
W, S, D
  Long-legged Myotis (M. volans
W, S, D
  Hoary Bat (Lasiurus cinereus
W, S, D, C
  Silver-haired Bat (Lasionycteris noctivagans
W, D
  Big Brown Bat (Eptesicus fuscus
W, S, D
species was captured at over 50 percent 
brown bats (N = 2). Percentage of captured 
of the sites surveyed and occurred in all 
females that were lactating was 83, 83, and 
habitat types at elevations ranging from 
33 percent for long-legged myotis, western 
1470 m to 1770 m (Appendix A). Other 
long-eared myotis, and little brown mytois, 
broadly distributed species included hoary 
respectively. Females were captured at 
bats (Lasiurus cinereus) and big brown 
elevations ranging from 1340 m to 1780 m 
bats (Eptesicus fuscus), both of which were 
(Appendix A). 
captured at 40 percent of sites. Hoary bats 
were captured in all habitat types while 
big brown bats were captured in three of 
We recorded the presence of 8 bat 
the four. While relatively high numbers of 
species at 15 sites in southwestern Montana. 
fringed myotis were captured, the majority 
Fifteen bat species occur in Montana with 
of these individuals (73%) were all captured 
12 of these species believed to be distributed 
at one site (Appendix A). Western small-
in the western part of the state (Foresman 
footed myotis (M. ciliolabrum) and silver-
2001). The four species believed to be 
haired bats (Lasionycteris noctivagans) were 
present in this part of the state that we did 
the least abundant species captured, but even 
not capture were townsend’s big-eared bat 
though few individuals of these species were 
(Corynorhinus townsendii), spotted bat, 
captured they were captured across multiple 
California myotis (M. californicus), and 
sites, habitats, and elevations.  
Yuma myotis (M. yumanensis). Echolocation 
Almost 80 percent of individual 
calls of spotted bats are audible to the human 
bats captured were males (Table 1). For 
ear, allowing species recognition without 
all species, with the exception of long-
direct capture (Leonard and Fenton 1983). 
legged myotis (M. volans) close to twice 
However, we did not audibly detect this 
as many males compared to females were 
species during any of our surveys. Montana 
captured. No female fringed myotis were 
is the north-eastern-most extension of the 
captured at any of the survey sites. Of the 
range of both California myotis and Yuma 
small number of female bats that were 
myotis (Foresman 2001) and it may be that 
captured (= 24), the majority (67%) 
both species are uncommon in the western 
were reproductive (lactating) at the time of 
part of the state. However, others (Hoffmann 
capture. The percentage of lactating females 
et al. 1969) have found California myotis 
ranged from 0% for hoary bats (N = 3) and 
to be relatively common in the Bitterroot 
western small-footed myotis (N = 1) to 100 
Valley in far western Montana. Townsend’s 
percent for silver-haired bats (N = 1) and big 
big-eared bats have been documented in the 
16          LaMarr and Kuenzi

counties that we surveyed (Foresman 2001). 
Literature cited
This species is found in a variety of habitats 
but it exists in low densities throughout its 
Adams, R. A. 2003. Bats of the Rocky 
range (Humphrey and Kunz 1976, Kunz and 
Mountain West. University Press of 
Martin 1982). Townsend’s big-eared bats are 
Colorado, Boulder.  289 pp.
also known to be highly maneuverable and 
Anthony, E. L. P. 1988. Age determination 
agile fliers (Fellers and Pierson 2002) which 
in bats.  Pp. 47-58 in T. H. Kunz, editor. 
make them difficult to capture in mist-nets. 
Ecological and behavioral methods for 
It is likely that they may have been present 
the study of bats. Smithsonian Institution 
at some of the sites we surveyed but a 
Press, Washington, D.C.
greater survey effort would be needed to 
Blehert, D. S., A. C. Hicks, M. Behr, C. U. 
detect them (Weller and Lee 2007).  
Meteyer, B. M. Berlowski-Zier, E. L. 
Fringed myotis were captured at 
Buckles, J. T. H. Coleman, S. R. Darling, 
three sites. This species is one of the six 
A. Gargas, R. Niver,  J. C. Okoniewski, 
bat species designated as Sensitive by the 
R. J. Rudd, and W. B. Stone.  2009. Bat 
Montana State Office of the BLM and one 
white nose syndrome:  an emerging 
of six species listed by the state as a Species 
fungal pathogen? Science 323:227.
of Concern. It has previously been collected 
Cryan, P. M., M. A. Bogan, and J. S. 
in lower elevation forest regions in the state 
Altenbach. 2000. Effects of elevation 
(Foresman 2001). We captured only males 
on distribution of female bats in the 
of this species and only at the high end of 
Black Hills, South Dakota. Journal of 
the range of elevations we surveyed. Many 
Mammalogy 81:719-725.  
studies have reported elevational differences 
in distribution among sexes of insectivorous 
Fellers, G. M., and E. D. Pierson. 2002. 
bats (Fenton et al. 1980, Grindal et al. 1999, 
Habitat use and foraging behavior of 
Cryan et al. 2000) with females occurring at 
Townsend's big-eared bat (Corynorhinus 
lower elevations.  
townsendii) in coastal California. Journal 
Thorough knowledge of the current 
of Mammalogy 83:167-177.
distribution of any species is necessary to 
Fenton, M. B. 1997. Science and the 
maintain existing populations. This study 
conservation of bats. Journal of 
contributes some important preliminary 
Mammalogy 78:1-14.
information on bat distribution in 
Fenton, M. B., C. G. van Zyll de Jong, G. P. 
southwestern Montana and identifies 
Bell, D. B. Campbell, and M. Laplante. 
sites that may be useful for future studies.  
1980. Distribution, parturition dates, and 
However, much work remains to be done. 
feeding of bats in south-central British 
Activity patterns of bats have been found to 
Columbia. Canadian Field-Naturalist 
vary both spatially and temporally (Hayes 
1997, 2000) and it is likely that our surveys 
did not detect all bat species present at 
Foresman, K. R. 2001. The Wild Mammals 
individual sites. More surveys and multiple 
of Montana. American Society of 
surveys at individual sites are recommended 
Mammalogists, Special Publication 
as well as studies that focus on roost and 
No. 12.
foraging site selection.
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 
We thank Cheryl Schmidt, Shauna 
Zoology 77:972-977.
Marquardt, and Joel Tigner for assistance in 
Hayes, J. P. 1997. Temporal variation 
the field.  Financial support was provided by 
in activity of bats and the design of 
the Bureau of Land Management. 
echolocation-monitoring studies. Journal 
of Mammalogy 78:514-524.
Bat Species Presence in Southwestern Montana       17

Hayes, J. P. 2000. Assumptions and 
Nicholson, A. J. 1950. A record of the 
practical considerations in the design and 
spotted bat (Euderma maculatum) 
interpretation of echolocation-monitoring 
for Montana. Journal of Mammalogy 
studies. Acta Chiropterologica 4:17-24.
Hendricks. P., D. L. Genter, and S. Martinez. 
Pierson, E. D. 1998. Tall trees, deep holes 
2000. Bats of Azure Cave and the Little 
and scarred landscapes: conservation 
Rocky Mountains, Montana. Canadian 
biology of North American bats. Pp. 309-
Field-Naturalist 114:89-97.
325 in T. H. Kunz and P. A. Racey.  Bat 
Hill, J. E. and J. D. Smith. 1984. Bats: a 
biology and conservation. Smithsonian 
natural history. University of Texas 
Institute Press, Washington, DC.
Press, Austin.
Racey, P. A. 1988. Reproductive assessment 
Hoffman, R. S., D. L. Pattie, and J. F. 
in bats. Pp. 31-45 in T.H. Kunz, editors, 
Bell. 1969. The distribution of some 
Ecological and behavioral methods for 
mammals in Montana. II. Bats. Journal 
the study of bats, Smithsonian Institution 
of Mammalogy 50:737-741.  
Press, Washington, DC. 533 pp.         
Humphrey, S. R. and T. H. Kunz. 1976. 
Saugey, D. A. 1991. U. S. National Forests: 
Ecology of a Pleistocene relict, the 
unsung home to America’s bats. Bats 
western big-eared bat (Pleucotus 
townsendii) in the southern Great Plains. 
Shryer, J. and D. L. Flath. 1980. First record 
Journal of Mammalogy 57:470-494.
of the pallid bat (Antrozous pallidus
Jones, J. K., Jr., R. P. Lampe, Spenrath, C. 
from Montana. Great Basin Naturalist 
A., and T. H. Kunz. 1973. Notes on the 
distribution and natural history of bats in 
Swenson, J. E. 1970. Notes on the 
southeastern Montana. Occasional Papers 
distribution of Myotis leibii in eastern 
of the Museum of Texas Tech University. 
Montana. Blue Jay 28:173-174.
Number 15.  12 pp.  
Swenson, J. E. and J. C. Bent. 1977. The 
Kunz, T. H. and R. A. Martin. 1982. 
bats of Yellowstone County, southcentral 
Plecotus townsendii. Mammalian Species 
Montana. Proceedings of the Montana 
Academy of Sciences 37:82-84.
Lampe, R. P., R. K. Jones, Jr., R. S. 
Swenson, J. E. and G. F. Shanks, Jr.  1979. 
Hoffmann, and E. C. Birney. 1974. The 
Noteworthy records of bats from 
mammals of Carter County, southeastern 
northeastern Montana. Journal of 
Montana. Occasional Papers Museum 
Mammalogy 60:650-652.
of Natural History, University of Kansas 
van Zyll de Jong, C. G. 1985. Handbook of 
Canadian Mammals. 2. Bats. National 
Leonard, M. L. and M. B. Fenton. 
Museum of Canada, Ottawa. 212 pp.
1983. Habitat use by spotted bats 
Weller, T. J. and D. C. Lee. 2007. Mist-net 
(Euderma maculatum, Chiroptera: 
effort required to inventory a forest bat 
Vespertilionidae): roosting and foraging 
species assemblage. Journal of Wildlife 
behavior. Canadian Journal of Zoology 
Management 71:251-257.
Nagorsen, D. W. and R. M. Brigham. 1993. 
Bats of British Columbia. UBC Press, 
Received 18 March 2011
Vancouver, BC.  164 pp.
Accepted 16 August 2011
18          LaMarr and Kuenzi

Appendix a. 
Locations of survey sites and species examined from southwestern Montana 2003-2006.
1.  Soap Gulch, Silver bow Co., Montana. G1,  E0373125 N50621362, 1830 m.  29 July 
2003 (9 net hrs).  Western Long-eared Myotis (1 male).  31 July 2003 (16 net hrs).  Western 
Small-footed Myotis (2 males), Western Long-eared Myotis (1 male), Little Brown Myotis 
 (1 male), Fringed Myotis (5 males), Hoary Bat (1 male), Big Brown Bat (1 male). 
2.   Moose Creek, Silver bow Co., Montana. W,  E0370035 N5066854, 1780 m.   
1 August 2003 (16 net hrs).  Little Brown Myotis (1 male), Fringed Myotis (16 males), 
Long-legged Myotis (2 females), Hoary Bat (2 males, 1 female), Big Brown Bat (1 male).  
19 July 2004 (6 net hrs).  Western Long-eared Myotis (5 males), Little Brown Myotis (5 
males), Long-legged Myotis (3 males, 2 female).  23 July 2004 (9 net hrs).  Little Brown 
Myotis (1 male).  19 July 2005 (8 net hrs).  Long-legged Myotis (1 male).  26 July 2006 (6 
net hrs).  Long-legged Myotis (1 female), Hoary Bat (1 male).
3.   West Fork, Silver bow Co., Montana. D, E0348436 N5078288, 2100 m.  8 August 2003  
(8 net hrs).  Fringed Myotis (1 male).
4.   Cottonwood Canyon, Jefferson Co., Montana. G, E0430659 N5080910, 1470 m.    
20 July 2004 (8 net hrs).  Western Long-eared Myotis (3 males).
5.   Upper whitetail, Jefferson Co., Montana. W, E0406504 N5097199, 1725 m.   
17 July 2004  (7 net hrs).   Little Brown Myotis (2 females, 1 male), Hoary Bat (4 males), 
Silver-haired Bat (1 male), Big Brown Bat (2 males).  24 July 2004 (6 net hrs).  Western 
Long-eared Myotis (2 females), Little Brown Myotis (1 female), Big Brown Bat (2 males).
6.   Lower whitetail, Jefferson Co., Montana. C, E048619 N5093058, 1550 m.  16 July 2004  
(6 net hrs).  Western Small-footed Myotis (1 female), Western Long-eared Myotis (1 male,  
2 females).  21 July 2005 (6 net hrs).  Western Long-eared Myotis (2 males, 1 female).
7.  Big Pipestone, Jefferson Co., Montana. D, E0399363 N5087441, 1560 m.  13 July 2004  
(6 net hrs).  Western Small-footed Myotis (1 male), Silver-haired Bat (1 male).
8.   Upper halfway, Jefferson Co., Montana. D, E0399358 N5089984, 1660 m.  14 July 2004  
(8 net hrs).  Western Small-footed Myotis (2 males), Western Long-eared Myotis  
(3 males), Big Brown Bat (1 male).
9.   Lower halfway, Jefferson Co., Montana. W, E0399572 N5088456, 1615 m.  15 July 2004  
(7 net hrs).  Western Long-eared Myotis (1 male).
10.  lower camp Creek, Silver bow Co., Montana. G, E0372520 N5056169, 1670 m.   
21 July 2004 (8 net hrs).  Big Brown Bat (1 male).
11.  Fish Creek, Silver bow Co., Montana. D, E0393478 N5073503, 1775 m.  20 July 2005  
(6 net hrs).  Western Long-eared Myotis (1 female), Silver-haired Bat (4 males).
12.  Crow Creek, Broadwater co., Montana. C, E0448048 N5122216, 1415 m.   
4 August 2006 (6 net hrs).  Hoary Bat (1 female).
13.  Lower bigfoot Creek, Jefferson Co., Montana. G, E0412510 N5106591, 1600 m.    
28 July 2006 (6 net hrs).  Long-legged Myotis (2 females).
14.  Lump Gulch, Jefferson Co., Montana. D, E0419972 N5148619, 1340 m.  29 July 2006  
(8 net hrs).  Little Brown Myotis (1 male), Long-legged Myotis (1 female), Hoary Bat  
(2 males), Silver-haired Bat (1 female), Big Brown Bat (2 females).
15.  Virginia Creek, Lewis And Clark Co., Montana. C, E0394331 N5193915, 1500 m.   
 1 August 2006 (7 net hrs).  Hoary Bat (1 female).
1Habitat Type (see Table 2).  
2Universal Transverse Mercator (UTM) Coordinates recorded in NAD 83.
3Net effort = number of nets X hrs open.  
Bat Species Presence in Southwestern Montana       19