48 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 64, Supplement 1 
Myotis melanorhinus, Dark-nosed Small-footed Myotis, roosts in rock-face crevices and 
riverbanks, and may use talus, tree bark or buildings; hibernation sites include mines and caves. 
The species has been seen in two mines in far southern California. 
Myotis occultus, Arizona Myotis, another obscure vespertilionid, it has only been seen in an 
abandoned copper mine in the Riverside Mountains, Mojave Desert. 
Myotis thysanodes. Fringed Myotis, known only in small numbers from seven mines from San 
Diego to Lake County. Danehy (1952) noted that this bat occurs in caves in central and southern 
California; roosts in caves, mines, and buildings. 
Myotis velifer, Cave Myotis, is co mm on across the southwestern U.S. to Central America. 
Danehy (1952) reported that this bat is common in the summer in sandstone and conglomerate 
caves near the Colorado River (Imperial, Riverside, San Bernardino counties). The subspecies 
M. v. brevis barely ranges into southeastern California. In summer, it congregates in caves and 
mines, and less often, buildings; winter roosts are primarily caves. California populations may be 
migratory, however we only have scant records from four mines in Riverside County. 
Myotis volans, Long-legged Myotis. Danehy (1952) reported that this was an uncommon bat 
in central and southern California caves, but is sometimes found with M. thysanodes. Barbour and 
Davis (1969) claim that this bat uses caves as night roosts only. Primarily inhabits forested moun¬ 
tain regions, where it roosts in trees, rock crevices, stream banks, and buildings; hibernation sites 
are primarily caves and mines. Records consist of three caves and three min es from southern to 
northern California. 
Myotis yumanensis, Yuma Myotis. Danehy (1952) notes only that this species is sometimes 
found with M. velifer in caves. Maternity colonies utilize buildings, caves, mines, or bridges. In 
1918 600 were observed in Old Senator Mine, Imperial County (U.S. Geological Survey 2016b). 
Fifty Yuma bats were counted in a Dam Canyon cave, San Diego County, in 2003. Our records 
include six mines, two tunnels, and five caves from southern to northern California. 
Parastrellus hesperus, Western Pipistrelle or Canyon Bat. Danehy (1952) reports that this bat 
is found in cracks in caves, but uncommonly. Primarily a desert species, it inhabits a variety of 
habitats from rocky canyons, cliffs, and outcroppings, to creosote bush flats; day roosts usually in 
rock crevices, mines, or buildings; hibernates in mines, caves, and rock crevices. Records include 
small numbers from nine caves and seven min es from southern to northern California. 
