A Demographic Comparison of a Hunted and an Unhunted Population of Black Bears in Northern Wisconsin

Abstract

We studied black bear (Ursus americanus) population dynamics on a hunted and an unhunted population in northern Wisconsin. One hundred thirty three bears were captured, marked, and followed from 1984-1994. The unhunted population increased to a density of 0.76 bears/km in 1994, then began to decline. The hunted population density was 0.36 and 0.34 bears/km in 1990 and 1992 respectively. Bears in the unhunted population had significantly smaller home range size, older age of primiparity, and lighter weights than those in the hunted population. We documented 4 cases of skipped breeding cycles in the unhunted population after 1992 and none in the hunted population. Survivorship rates were lowest for yearlings (45%) in the unhunted population and attributed to natural mortality (n=8). Cannibalism is suspected in many of these cases. One yearling in the hunted population died from natural mortality and cannibalism was also suspected in this case. Survivorship in the hunted population was lowest for subadult males (29%) and was due to harvest; two subadult males died from natural factors, perhaps cannibalism or starvation, in the unhunted population.