Reproductive ecology of bison on Antelope Island, Utah

Authors

Michael L. Wolfe, Utah State University
Milan P. Shipka, Utah State University
John F. Kimball, Utah Division of Wildlife Resources, Salt Lake City, Utah

Abstract

Autumn musters of bison (Bison bison) on Antelope Island State Park, Utah, conducted annually since 1987, provided data on temporal and age-specific reproductive patterns and a basis to evaluate the efficacy of management measures implemented to elevate reproductive performance in the herd. Pregnancy rates were variable and low (x̄ = 46.2%) in comparison to other free-ranging, noncommercial bison herds in North America. Cows in the 3- and >6-yr age classes exhibited lower-than-expected pregnancy rates (P < 0.05). Annual pregnancy rates showed a significant (r = 0.64, P = 0.047) linear decline of 2.5% per annum. Variance in distribution of fetal ages observed in 6 yr indicates substantial temporal fluctuation. Long-term reproductive performance of cohorts born prior to implementation of management measures did not differ from that of cohorts born subsequent to these changes.

Recommended Citation

Wolfe, Michael L.; Shipka, Milan P.; and Kimball, John F. (1999) "Reproductive ecology of bison on Antelope Island, Utah," Great Basin Naturalist: Vol. 59: No. 2, Article 1.
Available at: https://scholarsarchive.byu.edu/gbn/vol59/iss2/1