Monitoring the Population Dynamics of a Reintroduced Mountain Sheep Herd in the Sierra Nevada, California

Chow, L. S., J. A. Keay and P. E. Moore. 1990. Monitoring the population dynamics of a reintroduced mountain sheep herd in the Sierra Nevada, California. Examples Of Resource Inventory and Monitoring in National Parks of California: Proceedings of the Third Biennial Conference. C. Van Riper III, T. J. Stohlgren, S. D. Veirs, Jr., and S. C. Hillyer, Editors. pp103-109.

ABSTRACT: We monitored a reintroduced herd of mountain sheep (Ovis canadensis californiana) from March 1986 to March 1988. Study objectives included documenting reproduction, survival, and sources of mortality. Lamb:ewe ratios in 1986 and 1987 were 75:100 and 83:100 and lamb survival to one year of age was 67% and 60% respectively. Confirmed mortality for the first year was 33%, but actual mortality was probably higher (44%). During the second year, confirmed mortality declined to 10% while actual mortality was postulated at 20%. Primary sources of confirmed mortality were puma (Felis concolor) predation (43%) and exposure to severe post-release weather (29%).