O’SHEA, CRYAN & BOGAN: UNITED STATES BAT SPECIES OF CONCERN 
41 
nets set over water in forests of multiple types in northern Idaho (Lacki et al., 2007). None were 
taken among 205 bats of seven species netted or shot over water at beaver ponds and in nearby pon- 
derosa pine forest in the Long Pine Hills and Ekalaka Hills of southeastern Montana, at elevations 
of 1,036-1,158 m (Jones et al., 1973). Although they were captured in caves in the region and are 
widely distributed in Montana (Hoffmann et al., 1969), Townsend’s big-eared bats were not detect¬ 
ed in netting over water in the Pryor Mountains of south-central Montana, where nine other species 
and 231 individuals were taken (Worthington, 1991). 
California and Nevada: In California, the two most important determinants of distribution 
were thought to be the availability of roosting sites and the degree of human disturbance at the 
roosts (Pierson and Rainey, 1998a; see also: Pearson et al., 1952; Graham, 1966). Townsend’s big- 
eared bat ranked fourteenth out of 17 species (three individuals among 390 bats) captured in mist 
nets during 1993-1999 at 19 sites over a range of elevations in the Sierra Nevada Mountains of 
California, including Yosemite National Park (Pierson et al., 2001). Along montane areas around 
the upper Sacramento River in northern California, this was the least frequently captured of 15 
species taken in mist nets set over water, with one bat documented among 1,398 individuals cap¬ 
tured during four summers (Pierson et al., 1996b). They were also the least abundant bat observed 
using bridges as night roosts in montane hardwood and conifer habitats along the upper Sacra¬ 
mento River (elevations 320-730 meters), with two bats captured among 2,132 individuals of nine 
species documented using these structures at night (Pierson et al., 1996b). In the Mojave Desert, 
these bats were least abundant (three captures) among 6 species and 439 individuals sampled over 
water or nearby flyways at Fort Irwin National Training Center (Grinnell et al., 2012). 
Townsend’s big-eared bats were not documented in mist-netting surveys in Whiskeytown 
National Recreation Area in Shasta County, California, where 47 sites between 256 and 1,899 
meters elevation were sampled in a variety of habitats, ranging from chaparral to Douglas fir 
forests, and 403 bats of 10 other species were captured (Duff and Morrell, 2007). They also were 
not documented in a mist-net survey both over water and within forests (concentrating on groves 
of giant sequoia trees, Sequoiadendron giganteum) in Yosemite National Park in the California 
Sierra Nevada Range, where 10 other species and 284 individuals were captured (Pierson et al., 
2006). A survey based on mist netting over water in old-growth redwood forest in the Coast Range 
of northern California failed to document this species among 142 bats of seven species captured 
(Zielinski and Gellman, 1999). 
In the White and Inyo Mountains of Nevada and California, where they were taken in upper 
Mojave and Great Basin desert scrub through pinon-juniper woodland habitats, Townsend’s big- 
eared bats were low in abundance (three captures), ranking about twelfth of about 2,000 bats of 13 
species netted over water (Szewczak et al., 1998). Thirteen individuals were captured among 1,345 
bats of 13 species (ranking fifth) documented in mist nets set over very small watering sources in 
multiple habitats (but mainly desert scrub) at the Desert National Wildlife Refuge in Clark Coun¬ 
ty, southern Nevada, an area that includes abandoned min es (O’Farrell and Bradley, 1970; O’Shea 
et al., 2016b). Hall (2000) documented the species in Great Basin desert habitats on the Nevada 
Test Site in south-central Nevada, ranking eleventh with 11 captures among 2,099 individuals of 
13 species sampled over water. These bats ranked fourth (24 captures among 299 bats of 11 
species) in mist-netting surveys over water in west-central Nevada in habitats categorized as desert 
shrub and pinon-juniper woodland zones; this area included abandoned mines used as roosts by this 
species (Kuenzi et al., 1999). In the same general region of Nevada, radio-tracked Townsend’s big- 
eared bats tended to spend more time foraging in pinon-juniper habitat compared to its availabili¬ 
ty on the landscape (Ives, 2015). 
In eastern Nevada, mist netting over water and captures at abandoned mines and tunnels in six 
