Bighorn SheepEwe-juvenile band shedding its winter coat in the Crater of Rocky Mountain National Park (photo by M. Levine).Bighorn Sheep family courtesty of G. and J. BlanzBighorn Sheep courtesy of G. and J. Blanz2003 Bighorn Crew

Distribution and Abundance of Bighorn Sheep in Rocky Mountain National Park

Project Officer: Dana Winkelman
Principal Investigator: Gary White (CSU Fishery and Wildlife Biology)
Graduate Student: Brett McClintock
Project Start Date: 09/04/01
Expected Completion Date: 12/31/05
Funding Agency: USGS/BRD, RWO 67

Introduction: Little research effort has been expended on bighorn sheep populations in Rocky Mountain National Park (RMNP) since Goodson (1978, 1990). Bighorn sheep suffered a die-off from bronchopneumonia and other respiratory disease complications in the mid-1990's, and have not regained population levels observed prior to the die-off. We are developing estimates of population parameters to monitor the population.

Objectives: (1) Estimate population size (N) of the 4 herds from counts of radio-collared and unmarked animals using the methodology of program NOREMARK (White 1996). (2) Estimate movement rates between herds. (3) Estimate survival rates of adult ewes. (4) Estimate recruitment rates. (5) Develop baseline data on Pasteurella spp., Protostrongylus spp., and other agents responsible for pneumonia.

Progress: Fifty-nine ewes were captured and processed by 2 April 2003. Ground surveys were completed summer 2003-2004 and produced estimates of abundance, fecundity, recruitment, and movement. Samples collected at time of capture were analyzed and logistic regressions were performed to determine what diseases may be affecting survival. A 2003 preliminary research report was submitted to RMNP on 28 November 2003 and a 2004 preliminary research report was submitted on 1 February 2005. Overflights will be conducted summer 2005 to obtain an additional year of ewe survival data for use in projection matrices. A final report will be submitted fall 2005. Additional reports and publications will be produced when deemed appropriate.