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5.7 Biological Resources

Distribution is patchy and strongly correlated with the availability of caves and cave-like
roosting habitat, with population centers occurring in areas dominated by exposed, cavity-
forming rocks and/or historic mining districts. Townsend’s big-eared bat prefers open
surfaces of caves or cave-like structures (e.g., subsurface hard rock mines) and large
undisturbed spaces in buildings, bridges, and water diversion tunnels. Specific roosts may
be used only one time of year or may serve different functions throughout the year (such as
for maternity roosts, hibernation, or during the breeding season). Maternity colonies may
use multiple sites for different stages (pregnancy, birthing, and rearing). Males remain
solitary during the maternity season. Townsend’s big-eared bat appears to have fairly
restrictive roost requirements with temperature appearing to be critical. Townsend’s big-
eared bat is highly sensitive to human disturbance; however, in some instances it can become
habituated to reoccurring and predictable human activity (CDFW 2013). The Project site is
within this species’ known geographical range (Zeiner et al. 1990a). The Project site
contains suitable foraging habitat; however, no suitable maternity or hibernation roost
locations are known to be present on or in the immediate vicinity of the site. Therefore, the
Townsend’s big-eared bat has low potential to occur on the site for foraging.

Tipton Kangaroo Rat

The Tipton kangaroo rat (Dipodomys nitratoides nitratoides) is a federal and California
Endangered Species. It is one of three subspecies of the San Joaquin kangaroo rat (Dipodomys
nitratoides). The historical geographic range of Tipton kangaroo rat had a southern extent to
the northern foothills of the Tehachapi Mountains (Williams 1985). By 1986, the distribution
had been reduced to 3.7 percent of its historical acreage as a result of cultivation and
urbanization (Williams 1986). The 1986 range was primarily located in northwestern Kern
and southwestern Tulare Counties. The current acreage of occupied habitat is unknown, but
it probably does not differ much from the 1985 estimate (USFWS 1998). Tipton kangaroo rat
habitat is limited to arid-land communities occupying the valley floor of the Tulare Basin on
level or nearly level terrain. It occupies alluvial fan and floodplain soils ranging from fine
sands to clay-sized particles with high salinity. Much of the currently occupied habitat has
one or more species of sparsely scattered woody shrubs and a ground cover of mostly
introduced and native annual grasses and forbs. Woody shrubs commonly associated with
Tipton kangaroo rats are: spiny and common saltbushes, arrowscale (Atriplex phyllostegia),
quailbush (Atriplex lentiformis), iodine bush (Allenrolfea occidentalis), goldenbush
(Ericameria spp.), and honey mesquite (Prosopis glandulosa var. torreyana) (Williams 1985).
Tipton kangaroo rats live in ground burrows probably dug by the occupant or a predecessor
of the same species (Germano and Rhodehamel 1995). Neither historical nor recent
distributions of the Tipton kangaroo rat include the Project site (CDFW 2015a). The Tipton
kangaroo rat has not been observed on the Project site. It is not expected to occur due to the
large distance from the site to its current known range.

Western Mastiff Bat

The western mastiff bat (Eumops perotis), the largest bat in the United States, is a California
Species of Special Concern. The subspecies that occurs in Southern California is the California
mastiff bat (E. p. californicus). The western mastiff bat is a very wide-ranging and high-flying
insectivore that typically forages in open areas with high cliffs. This species roosts in small
colonies in crevices on cliff faces with a vertical drop of at least ten feet below the roost to

R:\Projects\PAS\CEN\000306\Draft EIR\5.7 Bio_051117.docx 5.7-125 Centennial Project
Draft EIR