2018-11-05_PERMIT FILE - C1981044A (3)

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The results of the Big Game Survey indicate that the Big Bottom area is important to a sizeable population of mule deer. In the winter, 30 to 40 deer were found bedding and browsing in tl~e peripheral sagebrush- filled gulches and on the sagebrush slopes above Big Bottom. In the evening, they moved down into the bottom itself to feed and to drink from the river. The habitats of the Big Bottom area are also important in the summer for fawning and feeding. Throughout the summer, as many alfalfa fields of the bottomland. The possible value of Big Bottom as part of the migratory route of elk is unknown, but doubtful. Big Bottom occasionally provides refuge for black bear; local reports indicate black bear's occasional presence in the area. Results of Small Mammal Trapping Throughout the year, the deermouse was the dominant small mammal observed in the Big Bottom study area as in other community types. Other small mammals captured in the trapping studies included shrews, moles, and chipmunks. Cottontails were fairly abundant in willow thickets in Big Bottom. Beavers were active at two-(2) locations along the river and there was evidence of porcupines in a number of river bottom cottonwood stands. Badger denning sites or excavations created by digging for prey were found. Skulls of coyotes and red foxes were also found. Active mounds and tunnelings of northern pocket gophers were observed in many areas of Big Bottom. Raccoons, muskrats, striped skunks, golden-mantled ground squirrels, and numerous bats were also captured or observed in the area. The population density was low for all small animals in the late fall trapping census period. The density was greatest on the Big Bottom transect, which traversed a variety of habitat types; however, density was still low even in this transect. Small mammal activity remained relatively low through. the early spring census period until the snow cover disappeared. By summer, and continuing into early fall, the size and species diversity of small mammal populations active in the study area increased substantially from the early study periods. The deermouse was the most abundant \ and widely distributed rodent, but the small mammal system took on a much more balanced appearance. . Considerable shifts in density occurred between study periods due to climatic factors, availability of food, and other biological factors. Sagebrush Stand Above Big Bottom The upland regions surrounding Big Bottom are utilized extensively for agriculture and pastureland. Much of the area is now being used for intensive dry land farming (wheat, sunflowers, and hay). The rest of the area is covered by a natural sagebrush community, which is grazed by sheep and cattle. The sampling location at the time of the study, has been free of grazing for several years. Several species of birds were observed in the upland sagebrush region near the temporary weather station. This area seems to be well used by sage grouse, but only lightly used by other species. The greater uniformity of vegetation in this area results in more restricted opportunities for food and shelter than exist in Big Bottom. Sagegrouse "strutting ground" of sage cocks is located in this sage community approximately two (2) miles southwest of the power plant site. The exact location of the "strutting ground" varies slightly from year to year, but the nests are dispersed over much of Big Bottom and the surrounding benches and ridges. The deermouse was the only small mammal found in the upland sage community during the late fall trapping period. The seasonal pattern of small mammal activity in this area was similar to that observed in the other communities. Activity remains low through the early spring until the snowmelts. During the summer and early fall, both numbers of diversity of small mammals active in the area increase substantially. Mule deer utilize the upland sagebrush community extensively for food as evidenced by tracks, droppings, and sightings of deer. Jackrabbits were noted in the upland sage community, but in moderate numbers only. Cottontails, ,~,~ porcupines, and other small rodents were also observed in this area. Raccoons, muskrats, striped skunks, golden- mantled ground squirrels, and numerous bats were captured or observed in the study area and in the vicinity of the APPR.OV~D F~~ 1 4 2D01 Permit Renewal No. 4 2.04-43 Revised 3/5/03