O’SHEA, CRYAN & BOGAN: UNITED STATES BAT SPECIES OF CONCERN 
65 
to nine bats roosting in a crevice in the ceiling of the cave during summer, and netted 11 bats (nine 
adult males, two females) at the cave entrance over the course of a night during August; they also 
inferred long-term use of this cave by the species based on mummified remains and a fossil. Four 
adult males were captured and radio tagged at this cave in summer 2003, but did not return during 
tracking (Chambers et al., 2011). 
Chambers et al. (2011) located 14 summer roosts of 12 individuals at three study areas across 
northern Arizona. Roosts were in cracks or crevices in upper sections of tall vertical cliffs that were 
between 130 and 850 meters in height within the rugged landscapes of Grand Canyon National 
Park, Vermilion Cliffs National Monument, Navajo Nation property, and Canyon de Chelly Nation¬ 
al Monument. Little roost switching was apparent: over a 10-day tracking period tagged bats used 
an average of only 1.4 roosts (Chambers et al., 2011), similar to findings of 1.6 roosts over a 
nine-day period in New Mexico (Bogan et al., 1998). Spotted bat roosts in the northern Arizona 
study were located at distances up to 36.3 kilometers from the point of capture, and averaged 
5.8 ±1.9 (SE) kilometers (range 0.4-18) from the nearest perennial water source (Chambers et al., 
2011). Seven females (six lactating or pregnant) were tracked to separate roosts, and all roosts 
faced in southerly directions, whereas aspects of five separate roosts of five males did not differ 
from random. Skin temperatures monitored for three bats tracked to roosts declined only 2.2 to 
2.9°C within the roosts, indicating little use of deeper daily torpor at this phase of the seasonal cycle 
(Chambers et al., 2011). Although the ability to count bats at emergence was limited, this species 
in the northern Arizona study did not seem to roost communally but mostly roosted as solitary 
adults. Two bats (one adult male, one post-lactating female) tracked to separate roosts in rock 
crevices in cliffs in the Okanagan Valley of southern British Columbia during August also roosted 
solitarily (Leonard and Fenton, 1983). Roosts in the Okanagan Valley were occupied regularly until 
late summer, when use became less predictable (Wai-Ping and Fenton, 1989). 
Roosts in Buildings: Although colonies of spotted bats have not been reported from buildings, 
there are rare reports of solitary bats found on porches (Hardy, 1941; Benson, 1954; Handley, 
1959), on a screen door (Rodeck, 1961), in a garage (Bleich and Pauli, 1988), under eaves of a 
schoolhouse (Durrant, 1935), in a warehouse (Mickey, 1961), and in 1903 and 1922 single indi¬ 
viduals flew into research laboratories on two campuses (Hall, 1935; Vorhies, 1935). Sherwin and 
Gannon (2005) reported use of a warehouse in Albuquerque New Mexico by a solitary bat and 
reviewed other occurrences of this species in buildings. Hall (1946) reported a solitary bat in a root 
cellar in Esmeralda County, Nevada, and several modem records of individuals taken among tall 
buildings in Reno and Las Vegas in Nevada suggested these structures may have been perceived as 
cliff faces by the bats (Geluso, 2000). 
Population Ecology. — Litter Size, Natality, and Female Reproduction: Litter size is 
one, based on three observations of single births (Easterla 1971, 1976), and one embryo reported 
in a pregnant spotted bat in Nevada (Geluso, 2000). Two lactating females had enlarged uterine 
horns on just one side (Findley and Jones, 1965). 
The limited available data from bats captured while foraging or drinking suggest natality may 
be high under typical conditions. Twenty-two among 26 (85%) adult females captured foraging in 
northern Arizona during summers 2003-2007 were either lactating or pregnant (Chambers et al., 
2011), and 17 of 24 (71%) adult females captured over water in Big Bend National Park, Texas dur¬ 
ing summers 1967-1971 were reproductive (Easterla, 1973). In New Mexico, each of six adult 
females captured over water in the Sacramento Mountains were lactating (Perry et al., 1997), and 
five of seven (71%) adult females captured while foraging in the Jemez Mountains during summers 
1995-1997 (including a drought year) were reproductive (Bogan et al., 1998). However, Geluso 
(2008) reported only one of four (25%) adult females captured on Mount Taylor in New Mexico as 
