Date of Award
Master of Science (MS)
Ground and aerial surveys conducted during this study revealed that the population size of bighorn sheep in southwestern North Dakota is between 200- 250. The present population began when 18 bighorn sheep from British Columbia were transplanted into an enclosure on Magpie Creek in McKenzie County. All surveys indicated a sex ratio approaching 100:100 with an annual reproductive success of 15-20%. Food habit analysis revealed that approximately 90% of the diet was browse and 10% grass. During spring, fall and winter, the dominant browse species in the diet was winterfat (Eurotia lanata), whereas in the summer buffaloberry (Shepherdia argentea) was the dominant. During fall, summer, and winter, the dominant grass species in the diet was western wheatgrass (Agropyron smithii), but in spring sedges (Carex spp.) were dominant.
Soil and plant samples were collected every month from the study sites during 1976. Tissue samples of bone, hoof, hair, skin, muscle, heart, liver, kidney, lung, spleen, rumen and feces were collected from 24 bighorn sheep during 1975-1976. All soil, plant and tissue samples were analyzed for calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), aluminum (Al), cadmium (Cd), copper (Cu), iron (Fe), lithium (Li), manganese (Mn), nickel (Ni), lead (Pb), strontium (Sr) and zinc (Zn). Analysis of plant and soil samples revealed seasonal fluctuations in the concentrations of all elements. Tissue analysis revealed that, with the exception of Fe, K and Na, all elements had their highest concentrations in the bone and hair. Trace element patterns for North Dakota samples were greatly different than those from other states.
Fairaizl, Steven D., "Bighorn Sheep in North Dakota: Population Estimates, Food Habits and Their Biogeochemistry" (1978). Theses and Dissertations. 2672.