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Utah State University (1969)

The Desert Bighorn Sheep of Southeastern Utah

Irvine Charles A.

Titre : The Desert Bighorn Sheep of Southeastern Utah

Auteur : Irvine Charles A.

Université de soutenance : Utah State University

Grade : Master of Science (MS) 1969

In April, 1967, this study was begun in a 211 -square-mile area, in the rugged, arid, Red Canyon area in San Juan County, southeastern Utah. Sixteen months were spent in the field to determine the population trend, migration, distribution, and the affect of water on distribution of the bighorn sheep. No migration was documented, but seasonal shifts did occur . The shifts were due to the availability of water in the free state and in plants . Dry periods forced sheep to remain close to seeps and springs. Lambing peaked in May and was over by June . Lou lamb mortality and high numbers of yearlings indicated a growing population which is re - covering from severe mortality during the uranium boom in the 1950’s. Sheep preferred browse but seasonal shifts occurred, grasses and forbs being preferred. Plants analyzed for protein proved adequate for gravid and lactating domestic ewes, and this is believed adequate for wild sheep. However, plants were found to be deficient in phosphorus.Parasites, disease and poisonous plants were not found to be limiting factors during the study. A 50-50 sex ratio, expected in a wild, relatively unhunted population, was found during this study . Spermatogenesis t o some degree was evident in all trophy rams examined taken during the hunt. No biological reason to remove rams could be ascertained. Recommendations for management of the des ert bighorn sheep in s outheastern Utah include removing cattle from she e p ranges, water development and maintenance, continued ewe -lamb surveys , hunting of trophy animals, and studying a ll wild sheep populations in the state .


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