64 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
In the most extensive analysis to date, fecal samples were examined from 33 individuals cap¬ 
tured in northern Arizona and stable carbon and nitrogen isotopic signatures of prey were used in 
combination with prey identification to infer dietary habits (Painter et al., 2009). Lepidopterans 
were over 99% of the diet by volume in two separate summers, and isotopic composition of feces 
indicated that most of the insects consumed by this species were moths of the families Noctuidae, 
Lasiocampidae, and Geometride (Painter et al., 2009). 
Roosting Habits. — Winter Roosts: Observations of winter roosts in caves or mines are 
limited. Four individuals were observed hibernating in a cave above a pool in Kane County, Utah 
during February 1930 (Hardy, 1941), one spotted bat was observed in a cave or tunnel in San 
Bernardino County, California in 1948 (Parker, 1952), and more recently, Geluso (2000) reported 
four records of solitary individuals from two caves in Nevada. Mead and Mikesic (2001) described 
use of a cave in northern Arizona by this species during warm months but did not verify its use as 
a winter roost. Sherwin and Gannon (2005) reported use of a warehouse in Albuquerque, New 
Mexico by a solitary spotted bat during three winters. 
Given the warm season roosting habits of spotted bats (see below) it is likely that they may 
favor deep rock crevices for winter roosts similar to those used in summer (see below). They have 
been captured drinking during winter at ambient temperatures as low as -5°C at water sources in 
washes in southwestern Utah near roosting places in cliffs; these pools were also used for drinking 
during warmer months, suggesting local hibernation (Ruffner et al., 1979; Poche, 1981). 
Warm Season Roosts: Spotted bats roost primarily in crevices in cliffs and canyon walls. 
Easterla (1970, 1973) first noted the likelihood that these bats were cliff-crevice roost specialists 
based on observations of individuals in flight in Texas, and by following 13 bats by eye as they 
flew to cliffs and crevices after release in early morning daylight at Big Bend National Park. Roosts 
of three solitary individuals were located in southwestern Utah by searching for and inspecting 
crevices in cliff faces with mirrored sunlight, but none were found roosting during searches of local 
caves (Poche, 1981). Several others captured in this area and in adjacent Arizona were released and 
followed with binoculars as they flew towards cliff walls, with some seen alighting on vertical sur¬ 
faces and entering rock crevices (Poche and Bailie, 1974; Poche and Ruffner, 1975; Poche, 1975, 
1981). 
Eight roosts of five spotted bats were found by radio tracking for five to 14 days each in the 
Jemez Mountains of New Mexico during summers 1995-1997. Roosts were located in crevices in 
cliffs from seven to 21 meters or more above ground (Bogan et al., 1998). Colony sizes ranged 
from one to 30 bats, elevations ranged from 2,005 to 2,287 meters, distances from initial capture 
point ranged up to 17.6 kilometers, and cliffs with roosts were southeast-facing (Bogan et al., 
1998). Six of seven individuals were radio tracked to roosts at Mesa Verde National Park in south¬ 
western Colorado in 2006-2007; they roosted exclusively in crevices in cliff faces on steep canyon 
walls 10-15 meters high at a distance averaging 10.8 ± 3.8 (SD) kilometers from the point of cap¬ 
ture and an average elevation of 1,968 ± 44 (SD) meters (O’Shea et al., 2011a). Emergence counts 
at two widely separated roosts at Mesa Verde suggested colony sizes of 12 and 18 bats. 
Five lactating females were radio tracked to five separate roosts after being captured while for¬ 
aging over meadows in subalpine ponderosa pine and Douglas fir forests at elevations of 2,400- 
2,650 meters on the Kaibab Plateau of northern Arizona (Rabe et al., 1998b; Siders et al., 1999). 
Roosts were located high on cliffs 38 to 43 kilometers from the point of capture in remote areas of 
Grand Canyon National Park or the Kanab Wilderness Area, all in Sonoran Desert habitat at 700- 
1,080 meters elevation. Colony size estimates were not possible. Similarly, one female and five 
males radio tagged on the Arizona strip in extreme northwestern Arizona roosted in cracks, 
crevices, or holes in upper portions of tall cliffs where exit counts were not possible (Herder, 1998). 
Mead and Mikesic (2001) reported on a cave in northern Arizona used by spotted bats, noted six 
