Mortality Patterns of White-Tailed Deer in Michigan's Upper Peninsula

Abstract

We radiotracked 95 white-tailed deer (Odocoileus virginianus, all age classes) in Michigan's Upper Peninsula between January 1992 and January 1995 for a total of 38,888 deer-days. Fifty-eight deer died: 12 due to predation, 6 due to malnutrition, 14 due to other or unknown sources, and 26 killed by hunters (including 1 that was poached). Analysis of mortality indicated rates of annual nonhunting mortality were 0.19 (SE = 0.09) for adult females, 0.00 (SE = 0.05) for adult males and yearling females, and 0.16 (SE = 0.07) for yearling males. Hunting mortality was 0.04 (SE = 0.10) for adult females, 0.72 (SE = 0.12) for adult males, 0.12 (SE = 0.09) for yearling females, and 0.47 (SE = 0.10) for yearling males. Hunting mortality was higher among males in both age classes (P < 0.01) though nonhunting mortality was equivalent (P ≥ 0.05). Seasonal mortality rates of males and females differed during the fall (P < 0.001), coincident with Michigan's hunting seasons. Hunting mortality was significantly higher for yearling and adult males due to hunting regulations that limited harvest of antlerless deer; consequently, adult sex ratios were skewed towards females.