Part 5

Juniperus scopulorum Symphoricarpos oreophilus Artemisia ludoviciana Sitanion hystrix Stipa comata Astragalus scopulorum Artemisia tridentata Chrysothamnus depressus Helianthus annuus Tetradymia canescens Quercus gambelii Bromus tectorum Poa fendleriana Lupinus caudatus Yucca baccata Sphaeralcea coccinea Eriogonum umbellatum Amelanchier utahensis Fendlera rupicola Lomatium pinatasectum

Individuals of P. maniculatus and of Reithrodontomys megalotis were caught (Table 1).

TABLE 1--Major Trapping Localities in Mesa Verde National Park, Colorado.

Vegetational Key as Follows: 1) Pinyon-Juniper-Muttongrass 2) Pinyon-Juniper-Mixed Shrubs 3) Juniper-Pinyon-Bitterbrush 4) Juniper-Pinyon-Mountain Mahogany 5) Grassland with Mixed Shrubs 6) Big Sagebrush 7) Pinyon-Juniper-Big Sagebrush 8) Grassland.

Column headings:

A: Date B: No. trap nights C: P. truei D: P. man. E: Type of vegetation

========================+=============+=======+=====+=====+=== Locality | A | B | C | D | E ------------------------+-------------+-------+-----+-----+--- Morfield Ridge | Sept. 1961 | 1080 | 0 | 83 | 5 | Oct. 1963 | 360 | 0 | 13 | 5 | | | | | S. of Far View | Oct. 1961 | 360 | 10 | 13 | 2 | | | | | W. of Far View | Oct. 1961 | 1080 | 22 | 17 | 2 | | | | | South Chapin Mesa | Nov.-Dec. | 3600 | 16 | 9 | 6 | 1961 | | | | | | | | | East Loop Road | Jan. 1962 | 720 | 6 | 2 | 2 | | | | | Navajo Hill | May 1962 | 720 | 0 | 18 | 5 | Aug. 1964 | 20 | 0 | 2 | 5 | Aug. 1965 | 50 | 0 | 8 | 5 | | | | | N. Wetherill Mesa | May-June | 1080 | 0 | 57 | 5 | 1962 | | | | | | | | | Bobcat Canyon Drainage | June 1962 | 360 | 0 | 0 | 6 | | | | | N. of Long House | June 1962 | 1080 | 3 | 4 | 1 | | | | | Mug House--Rock Springs | Aug. 1962 | 720 | 8 | 14 | 4 | Aug. 1963 | 720 | 9 | 7 | 4 | | | | | S. Wetherill Mesa | Aug. 1962 | 720 | 0 | 5 | 3 | | | | | 1 mi. SE Park Entr. | June 1963 | 50 | 0 | 16 | 7 | | | | | 1/4 mi. SE Park Entr. | July 1963 | 100 | 0 | 7 | 8 | | | | | M-2 Weather Sta. | May 1964 | 25 | 2 | 0 | 1 | | | | | 8 mi. S North Rim | | | | | Moccasin Mesa | Aug. 1964 | 100 | 0 | 3 | 8 | | | | | 10 mi. S North Rim | | | | | Moccasin Mesa | Aug. 1964 | 25 | 2 | 0 | 2 ------------------------+-------------+-------+-----+-----+---

Bobcat Canyon Drainage

Bobcat Canyon, a large secondary canyon on the eastern side of Wetherill Mesa, is a major drainage for much of the mesa at its widest part. The mesa top drains southeast into a pour-off at the head of Bobcat Canyon. A stand of big sagebrush, Artemisia tridentata, grows in the sandy soil of the drainage, and extends northwest for several hundred yards from the pour-off. The sagebrush invades the pinyon-juniper forest at the periphery of the area.

Two traplines were set in the drainage, with trapping stations at intervals of 25 feet. The lines traversed elevations of 7,000 to 7,100 feet, and were run from June 26 to 29, 1962.

Grasses are the most abundant plants in the ground cover. Artemisia dracunculus is common in the drainage, and A. nova grows around the periphery of the drainage. Other species occurring in this stand include:

Aster bigelovii Tetradymia canescens Tragopogon pratensis Bromus tectorum Poa fendleriana Sitanion hystrix Stipa comata Lupinus argenteus Calochortus gunnisonii Sphaeralcea coccinea Phlox hoodii Eriogonum umbellatum Peraphyllum ramosissimum Purshia tridentata Penstemon linarioides

No mice were caught in three nights of trapping (360 trap nights), and only one mammal, a Spermophilus variegatus, was seen.

North of Long House, Wetherill Mesa

Pinyon-juniper forest with a dominant ground cover of Poa fendleriana was described by Erdman (1962) as one of the three distinct types of pinyon-juniper woodland on Wetherill Mesa. Such a woodland occurs adjacent to the Bobcat Canyon drainage, and is continuous across the Mesa from above Long House to the area near Step House. Plants in the ground cover include:

Cryptantha bakeri Opuntia rhodantha Chrysothamnus depressus Solidago petradoria Koeleria cristata Lupinus argenteus Yucca baccata Phlox hoodii Eriogonum racemosum Eriogonum umbellatum Cordylanthus wrightii Pedicularis centranthera Penstemon linarioides Penstemon strictus

Two traplines were run from July 9 to 12, 1962, in the area south of the Bobcat Canyon drainage at an elevation of 7,100 feet. No mice were caught in three nights of trapping. Four additional lines were established on July 24, 1962, and were run for three nights, in the area north of the Bobcat Canyon drainage at elevations of 7,100 to 7,150 feet.

P. maniculatus and P. truei were caught here (Table 1). This vegetational association may have few rodents because there is a shortage of places where they can hide. Although Poa fendleriana is abundant, the lack of shrubs leaves little protective cover for mammals.

Mug House--Rock Springs

A juniper-pinyon-mountain mahogany association extends from the area of Mug House to Rock Springs, on Wetherill Mesa. On that part of the ridge just above Mug House, the understory is predominantly Cercocarpos montanus (mountain mahogany), but northward toward Rock Springs the understory changes to Fendlera rupicola, Amelanchier utahensis, Cercocarpos, and Purshia tridentata. The ground cover is essentially the same as that in the pinyon-juniper-muttongrass association described previously.

Four traplines were run from July 31 to August 2, 1962, and from August 13 to 15, 1963. These lines ran northwest-southeast, starting 1,000 feet southeast of, and ending 3,000 feet northwest of, Mug House. The lines traversed elevations of 7,225 to 7,325 feet. Individuals of P. maniculatus and P. truei were caught here (Table 1).

Deer and rabbits inhabit the trapping area. Bobcats have been seen, by myself and by others, near Rock Springs. Lizards of the genera Cnemidophorus and Sceloporus, as well as gopher snakes were seen in this area.

Juniper--Pinyon--Bitterbrush

Three pairs of traplines were run from August 7-9, 1962, in a juniper-pinyon-bitterbrush stand on the southern end of Wetherill Mesa, starting 200 yards southwest of Double House (Fig. 1).

The forest on the southern end of the mesas consists of widely-spaced trees, which reflect the low amounts of precipitation at these lower elevations. Juniper trees are more numerous than pinyons, and both species are stunted in comparison to trees farther north on the mesa. Purshia tridentata (bitterbrush) is the understory codominant. Artemisia nova (black sagebrush) is present and grasses are the most abundant plants in the ground cover. Herbaceous species in the sparse ground cover include the following:

Opuntia polyacantha Solidago petradoria Lathyrus pauciflorus Penstemon linarioides Lupinus caudatus Yucca baccata Phlox hoodii

Only P. maniculatus was caught in this stand; all mice were caught in the first night of trapping.

Five areas were selected for trapping in the summers of 1963 or 1964, in order to test hypotheses concerning habitat preferences of each of the species of Peromyscus. Four of these areas appeared to be ideal habitat for one species, but not for the other. The fifth area was expected to produce both species of Peromyscus. Each of these areas is discussed below.