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and Pynh (1974) found, when comparing successful to unsuccessful nests,tha[ successful nests were located in <br />• stands of sagebrush with a higher average canopy cover (27 percent) than those of unsuccessful nests (20 percent). <br />Taller sagebrush stands also may provide a food supply to grouse after early snows cover the shorter sagebrush <br />communities, although, Gill (1965) found that birds in his study preferred to feed on the short (less than I I in), <br />less vigorous sagebrush plants. He postulated that grouse preferred shorter, less vigorous sagebrush since these <br />shrubs exhibited significantly lower levels of essential oils in their foliage than the taller (greater than I I in), more <br />vigorous sagebrush plants. <br />Sagebrush/meadow communities become valuable forage sites for grouse as summer progresses and forbs <br />dessicate in the dryer, more upland, mountain and low sagebrush communities. Two authors, Savage (1969, as <br />cited in Autenrieth e[ al. 1982) and Oakleaf (1971, as cited in Autenrieth e[ al. 1982) have suggested than, in <br />Nevada, mesic upland meadows are important summer habitats for young broods, and [hat [hey provide a source of <br />food (forbs), water, and cover unavailable in more xeric adjacent rangelands. Vegetation information (see <br />Response to Rule 2.04.10) presented in [his permit application shows that forb production in sagebrush/meadow <br />(37.9 g/m2) was greater than that in the two upland sagebrush communities (22.6 ghn2). This difference in forb <br />production is likely to become more pronounced as summer progresses and moisture decreases in the upland <br />communities. In most areas the sagebrush/meadow community is also a source of surface water for grouse. <br />Throughout their range, studies of sage grouse food habits have documented that they are solely dependent on <br />sagebrush from October through April (Dorgan et al. 1942, Patterson 1952, Klebenow and Gray 1968, Peterson <br />1970). In May, sage grouse shift to aforb-dominated diet and then shift back to sagebrush in September. Use of <br />sagebrush communities by sage grouse during these months is controlled primarily by snow cover and the <br />availability of uncovered sagebrush. In Montana, Eng and Schladweiler (1972) found that sage grouse winter <br />• range was characterized by large expanses of dense sagebrush (over 20 percent canopy coverage) on land having <br />little if any slope. Beck (1975) and Gill (1965) concluded that selection of wintering areas is dependent on snow <br />accumulation and that grouse avoided areas where sagebrush was not available above snow cover. Gill (1960 <br />observed winter concentrations of grouse in areas of rolling or broken topography where wind-swept ridges were <br />free of snow. Winter concentrations of grouse in Beck's (1975) study were found primarily on west, southwest, <br />south, and southeastern exposures with slopes of less than 10 percent. Beck's (1975) study also indicated that <br />seasonal movements to winter range vary with topography, vegetative cover, and the severity of winter weather. <br />In the permit area, south-facing slopes and wind-swept ridge tops are [he most likely places to remain snow free. <br />Sagebrush communities in these areas are limited as a result of cultivation, and only a few south-facing slopes still <br />support small stands of low sagebrush. Monthly aerial surveys (1980-84) by [he Applicant's biologists indicate <br />that sagebrush communities in Twentymile Park are completely snow covered by mid-winter, except during the <br />mildest winters. Based on these qualitative observations and the small extent of potentially snow-free sagebrush <br />habitat, i[ is assumed that, during most winters, sage grouse populations in Twentymile Park move out of the park <br />to more suitable habitat in adjacent areas. <br />In summary, sagebrush communities in the permit area provide suitable breeding, nesting, brood-rearing, and <br />feeding habitats for sage grouse. Sage grouse are likely to occur in the permit area from early spring through early <br />winter but normally move out of the permit area to winter, except during mild winters when sufficient sagebrush <br />habitat is exposed above snow cover. <br />Results of the Sandhill Crane Nesting Surveys <br />. The greater Sandhill crane occurs in northwest Colorado as a breeding species and a migrant. The breeding <br />population is classified as an endangered State subspecies. Northwest Colorado greater Sandhill cranes are part of <br />MR97-1~4 2.04-T Revised 10/02/97 <br />