Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Mule Deer Survival in Colorado, Idaho, and Montana

James W. Unsworth, David F. Pac, Gary C. White and Richard M. Bartmann
The Journal of Wildlife Management
Vol. 63, No. 1 (Jan., 1999), pp. 315-326
Published by: Wiley on behalf of the Wildlife Society
DOI: 10.2307/3802515
Stable URL: http://www.jstor.org/stable/3802515
Page Count: 12
  • Download ($42.00)
  • Subscribe ($19.50)
  • Cite this Item
Mule Deer Survival in Colorado, Idaho, and Montana
Preview not available

Abstract

We examined survival rates of mule deer (Odocoileus hemionus) fawns (1 Jan-31 May) and adult (≥1 yr old) females (1 Jun-31 May) from Colorado, Idaho, and Montana to assess the influence of survival on population dynamics over a broad geographic area. Survival rates were estimated from 1,875 radiocollared fawns and 1,536 radiocollared adult female-years. We found significant year-to-year differences in overwinter survival rates of fawns among states (P < 0.001), while annual survival rates of adult females showed less variation across years (P < 0.256). Sampling distributions of survival rates by age class were modeled with the beta-binomial distribution (BBD) and not found different among states (ad F: P = 0.118; fawns: P = 0.856). The mean overwinter survival rate for fawns was 0.444 (SE = 0.033), with SD = 0.217 (SE = 0.019). The mean annual survival rate for adult females was 0.853 (SE = 0.011), with SD = 0.034 (SE = 0.014). All 3 states exhibited differences in body size of fawns at the start of winter across years, and body size was a predictor of overwinter survival (P < 0.001). Fawn sex ratios in December at time of capture were not different from 50:50 (P = 0.729). However, a sex differential in overwinter survival of fawns was observed (P = 0.002), but beta-binomial models of survival distributions were not different between sexes (P = 0.458). Frequencies of 3 categories of proximal causes of fawn mortality (predation, winter malnutrition, other) differed among states (χ 2 4 = 41.24, P < 0.001). A deterministic model with a mean winter survival rate of 0.444 for fawns and an annual rate of 0.853 for adult females predicted December fawn: doe ratios would have to be at least 66: 100 to maintain population levels. Similarity of mule deer population dynamics across the 3 states suggests similar processes regulate these populations; hence, results from specific study areas are generally more applicable than commonly thought.

Page Thumbnails

  • Thumbnail: Page 
315
    315
  • Thumbnail: Page 
316
    316
  • Thumbnail: Page 
317
    317
  • Thumbnail: Page 
318
    318
  • Thumbnail: Page 
319
    319
  • Thumbnail: Page 
320
    320
  • Thumbnail: Page 
321
    321
  • Thumbnail: Page 
322
    322
  • Thumbnail: Page 
323
    323
  • Thumbnail: Page 
324
    324
  • Thumbnail: Page 
325
    325
  • Thumbnail: Page 
326
    326