Field Guide to Mammals
of Southern California
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San Bernardino White-Eared Pocket Mouse (Perognathus alticolus alticolus)
Records of occurrence for this subspecies on National Forest System lands are all from the vicinity of Strawberry Peak and Little Bear Valley in the western San Bernardino Mountains at elevations of 5,400– 5,800 feet (1,646–1,768 meters) (Best 1994, Williams 1986). These are old museum collections; San Bernardino white-eared pocket mouse has not been collected since 1934 despite extensive surveys to relocate it in the late 1970s and early 1980s (Sulentich 1983, Williams 1986). There was one partially eaten Perognathus, probably P. alticola alticola according to the notes, taken from the base of Sugarloaf Mountain at 7500' (Williams 1986).
White-eared pocket mouse is an isolated allospecies of Great Basin pocket mouse (Perognathus parvus) (Williams 1986). Hall (1981) recognized two subspecies of white-eared pocket mouse (also known as P. alticola): San Bernardino white-eared pocket mouse (P. a. alticolus), and Tehachapi white-eared pocket mouse (P. a. inexpectatus). Both of these species probably represent a relict distribution of P. parvus in California (Zeiner and others 1990).
Little is known, but historic white-eared pocket mouse localities were in open pine forests containing bracken ferns, in grassy flats among scattered ponderosa pines and Joshua trees, and in pinyon-juniper woodland habitats (Best 1994). Williams (1986) suggests that San Bernardino white-eared pocket mouse may occur in sagebrush, pinyon-juniper woodlands, and open pine forests on the north side of the San Bernardino and possibly the San Gabriel Mountains. Potential habitat may also occur on the Angeles National Forest.
There is no information available on the reproductive biology of white-eared pocket mouse. The congeneric Great Basin pocket mouse breeds from May to July, and one or two litters may be produced. The breeding period can extend into fall when conditions are favorable. The gestation period is 21–25 days, and the average litter size ranges from 3.9 in south-central Washington to 5.6 in Nevada (USDA Forest Service 2002).
White-eared pocket mouse is nocturnal and uses underground burrows for cover and rearing of young. This species may enter torpor during high summer and low winter temperatures (Best 1994).
Diet and Foraging
In captivity, white-eared pocket mice eat rolled oats, sunflower seeds, and vegetable greens; however, no data are available on the natural diet of this species (Best 1994). Great Basin pocket mice consume primarily grass and forb seeds, but will occasionally eat some green vegetation and insects (USDA Forest Service 2002).
No information is available.
Common predators of pocket mice include owls, hawks, foxes, skunks, and snakes.
Best, T.L. 1994. Perognathus alticolus. American Society of Mammalogists. Mammalian Species 463: 1- 4.
Hall, E.R. 1981. The mammals of North America. 2d ed. New York: John Wiley & Sons.
Sulentich, J.M. 1983. The systematics and evolution of the Perognathus parvus species group in southern California (Rodenetia: Heteromyidae). Long Beach: California State University. M.S. thesis. USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. 2002, January. Fire Effects Information System. [Online]. Available: http://www.fs.fed.us/database/feis/.
Williams, D.F. 1986. Mammalian species of concern in California. California Department of Fish and Game Report 86-1. Sacramento, CA: California Department of Fish and Game.
Winter, K. 1998. San Bernardino white-eared pocket mouse. Region 5 U.S. Forest Service sensitive animal species evaluation and documentation form. USDA Forest Service, unpublished data.
Zeiner, D.C.; Laudenslayer, W.F., Jr.; Meyer, K.E.; White, M., eds. 1990. California's wildlife. Volume III: Mammals. California statewide wildlife habitat relationships system. Sacramento, CA: California Department of Fish and Game.
Information gathered from California DFG - California Interagency Wildlife Task Group