Milpitas Wash

Lying to the west of the Cibola National Wildlife Refuge, this wash is one of the largest virtually undisturbed examples of the Sonoran Desert remaining in the State. A variety of plant and animal communities is found here, including desert mountain foothills, wash and floodplain habitats, and creosote bush flats. The latter comprises much of the area, with Larrea tridentata dominant. In the washes and adjacent areas, mesquite, Prosopis glandulosa var. torreyana, desert ironwood, Olneya tesota, palo verde, Cercidium floridum, Acacia greggii and Atriplex spp. are common.

On Palo Verde Mountain, in one of its few occurrences in the State, there are a number of saguaros, Carnegiea gigantea.

The mammal population is typical and includes the leafnose bat, Macrotus californicus, several Myotis species, at least 13 rodents including the Merriam and desert kangaroo rats, Dipodomys merriami and Dipodomys deserti, and the longtail and little pocket mice, Perognathus formosus and Perognathus longimembris, etc. The desert bighorn, Ovis canadensis nelsoni, has been sighted in the area.

There is a rich bird and reptile population here; among the latter is the protected desert tortoise, Gopherus agassizi, and numerous snakes including the Western diamondback rattler, Crotalus atrox.

The floodplain is Quaternary alluvium and is drained by a wide, well-developed wash fed by a number of tributaries. Water is found in the temporary rain pools and during the frequent flash floods. There are petroglyphs in the area.

Integrity: Highway 78 traverses the area. There are some dirt roads as well as ranch and other structures in the area.

Use: Research, educational, observational.

August 1982