Recent dynamics and mortality rates of the Kaibab deer herd

Abstract

Survival rates and expected sex ratios are estimated for the Kaibab mule deer (Odocoileus hemionus) of north central Arizona from harvest age–frequency distributions. During the study period (1972–1979) the population was declining at 9% per year. Annual survival rates for females older than 1.4 years were 0.63 and 0.62 for the eastern and western overwintering herds, respectively. For males older than 3.4 years, the corresponding rates were 0.50 and 0.44, respectively. These survival rates did not change appreciably with age beyond 1.4 years for does and 3.4 years for bucks. When survival rates were adjusted by subtracting reported firearm harvests, the rates show only a small difference between the sexes. Sex ratios estimated from the survival rates differed markedly from field estimates. Possible biases in both the field methods and in the use of harvest age distributions to infer population age structure are examined. The potential value of analyses of age distributions is discussed with regard to augmenting and independently verifying field data.