72 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
ifomia were visited by Pierson and Rainey (1998c) to search for this species and to monitor for 
their distinctive echolocation calls. They confirmed the continued occurrence of greater bonneted 
bats in many regions and added additional distribution records. However, few colonies were 
observed directly, and all colonies were small (less than 100 individuals). Possible switching 
among alternate roosts and the capability of individuals to forage over great distances may possi¬ 
bly inflate their seeming abundance. 
Greater bonneted bats were confirmed in flight during the 1990s at a site in the Coast Range 
in San Benito County, California where a roost was known to exist in 1940 (Dalquest, 1946), but 
the crevice utilized at that time had since eroded away (Pierson and Rainey, 1998c). In the Sierra 
Nevada, a roost on the Kern River which was occupied by about 100 bats in August 1948 was occu¬ 
pied by up to 75 bats in 1992. About seven new roost sites with colony maxima of about 60 bats 
were also located near Fresno and Jamestown, California. They were commonly detected in the 
central Sierra Nevada during the 1990s, where two roosts with evidence of breeding colonies were 
found (Pierson and Rainey, 1998c). In southern California, however, findings suggested serious 
reductions in populations in some areas, particularly the northern Los Angeles basin. In the latter 
area, places where these bats were common up through the 1960s lacked evidence for their occur¬ 
rence in the 1990s. Only one roost previously known to have bats was found occupied. Numbers 
at this roost had dropped from 40-50 adults in 1969 to three bats in 1992. 
Based primarily on acoustic surveys, Pierson and Rainey (1998c) reported that greater bon¬ 
neted bats still occur in western Riverside and San Diego Counties, California. Locations where 
three small (10-12 bats) colonies occurred in this region were determined in the early 1990s. One 
of these had been occupied in the 1940s. A fourth site where Vaughan (1959) had described an 
active colony no longer had evidence of bats, and was occupied by a housing subdivision. 
Management Practices and Concerns. — As with other bats not commonly represented in 
museum collections, requests for permits for scientific collecting should be reviewed carefully to 
insure that the activities do not pose a direct threat to colonies, as occurred with this species in the 
past. Cox (1965) for example, reported acquiring specimens from one of the only two known 
maternity colonies in Arizona by shooting into the roost crevice opening, as did Cockrum et al. 
(1996) at one of these sites during the 1960s, and Ohlendorf (1972) at a Texas colony. 
Many of the old buildings that provided suitable roosts for the greater bonneted bat in south¬ 
ern California have been razed (Pierson and Rainey, 1998c). These large bats can be noisy and 
obvious when roosting in buildings, stimulating attempts to exterminate them. The only two 
colonies known to exist in public buildings in southern California were partially exterminated by 
public health personnel as recently as 1991 (Pierson and Rainey, 1998c), and homeowners in Cal¬ 
ifornia were reported to have killed 20-30 individuals during an exclusion attempt because they 
roosted in an attic and were considered nuisances (Howell, 1920b). 
Impoundments that submerge cliff faces can eliminate roosting habitat. Mining and quarrying 
at cliffs and the construction of roads and bridges through cliff-walled canyons can impact colonies 
of these and other cliff-dwelling bats through blasting; in some areas recreational climbing can also 
increase disturbance (Pierson and Rainey, 1998c). An analysis of likely acceptance of gates by bat 
species based on wing and echolocation characteristics suggested greater bonneted bats might 
abandon roosts fitted with bat gates (Tobin and Chambers, 2017). 
Notes and Comments. — During World War II, a secret U.S. government program was aimed 
at using bats to carry small incendiary weapons; the principal investigator kept a pet greater bon¬ 
neted bat nicknamed “Flamethrower” that accompanied him during outings in the field, sometimes 
resting on his shoulder (Couffer, 1992). 
