Mammals of the Chiricahua Mountains, Cochise County, Arizona

Abstract

The following list is one of the results of a field study made during the summers of 1932 and 1933 in the Chiricahua Mountains of southeastern Arizona. This range runs in a general north-south direction for approximately 30 miles, while its maximum extension east and west is about 20 miles. Chiricahua Peak, the highest point, is 9,795 feet above sea level. The eastern base of the mountains, in the San Simon Valley, has an elevation of about 4,500 feet and the lowest place in the immediate region, the San Simon Cienega, is approximately 3,900 feet. On the western side, the Sulphur Springs Valley is at least 600 feet higher. The vegetation of the San Simon Valley is definitely that of the Lower Sonoran Zone or arid grassland belt. The upper limit of the zone, at 5,000 feet, practically coincides with the eastern base of the range, although it extends for a mile or two into the mountains on the floor of the wider canyons (Cave, Silver, and Whitetail creeks). The hot south slopes of some of the low foothills come within this zone. Mesquite, catclaw and creosote bush are the most prominent plants. Although somewhat more elevated, the Sulphur Springs Valley also belongs in the Lower Sonoran Zone. The west-facing exposure favors the accumulation of heat and this valley therefore has a relatively high average annual temperature. The Upper Sonoran Zone or encinal life belt is the most prominent life belt in the Chiricahuas and probably occupies more than 50 percent of the surface, at least on the eastern drainage. It is an area of steep-walled, often narrow, canyons which broaden and become shallow toward their sources. On the eastern slope, the altitudinal limits of the zone are from 5,000 feet to about 8,300 feet, while on the western side, where the drainage tends to turn in a somewhat northerly direction, the upper limit may be as low as 6,500 feet. The most abundant trees are oaks and junipers. Pinyon or nut pine (Pinus edulis), usually a characteristic species of the local forests of this type, is relatively scarce in the Chiricahuas. Above the Upper Sonoran Zone is the Transition, which is synonymous with the Yellow Pine Association of the montane forest life belt. It occupies the more level ground above the heads of the canyons, and extends nearly to the tops of the highest peaks except on the cold north slopes. Parks or grassy openings are common. The dominant tree species is ponderosa pine (Pinus ponderosa var. scopulorum). On the north slopes of Fly and Chiricahua peaks, and on the elevation south of Round Park, are relatively small patches of Engelmann spruce (Picea engelmannii) and large-toothed aspen (Populus tremuloides aurea). This 418