This ground squirrel inhabited the desert slope of the mountains up to 5000 feet elevation, and was most common in the juniper belt; burrows often were made under large junipers. In May, 1949, ground squirrels were common in the rocks adjacent to Mescal Wash at an elevation of 4500 feet. In an apple orchard near Valyermo, squirrels fed on the fallen fruit in early November of 1951.
No squirrel was seen in December, January, and February, indicating that all were below ground in winter.
Specimen examined.—San Bernardino County: Desert Springs, 4000 ft., 1 (PC).
Ammospermophilus leucurus leucurus (Merriam)
Antelope Ground Squirrel
Antelope ground squirrels were common in the Joshua tree woodland where they were noted up to 4500 feet elevation in Graham Canyon. None was found on the pinyon slopes, possibly because of the competition offered there by Eutamias merriami, or because the rocky nature of the soil there rendered burrowing difficult.
Although observed less often in winter than in summer, this species is active all year. On February 6, 1949, in Mescal Wash, an antelope ground squirrel was foraging over the snow which was at least six inches deep. These squirrels were attracted to the carcasses of rodents used as bait for carnivore sets, and caused a good deal of trouble by disturbing the traps.
Antelope ground squirrels used the topmost twigs of box-thorn bushes extensively as lookout posts, and many of their burrows were at the bases of these thorny bushes. This habit of regularly using observation posts is well developed in each species of ground squirrel found in the San Gabriels.
Specimens examined.—Los Angeles County: 6 mi. E and 1 mi. S Llano, 3500 ft., 2.