Hunting Efficiency and White-Tailed Deer Density

Abstract

A herd of 300 white-tailed deer (Odocoileus virginianus) on Griffith Island in Georgian Bay, Ontario, was reduced to 100 deer in a controlled hunt during the winter of 1967-68. Initially, when the density was about 100 deer per square mile, 0.65 deer were shot per hour; at the end of the hunt 0.16 deer were shot per hour. The number of deer killed per hour was equal to the number of deer per square mile times 0.006, the index of hunting efficiency. When hunter effort is measured to the nearest hour, the kill per unit effort can give a reliable index of population density for small areas. Most deer were shot with one shot and were within 100 m of the hunter. Hunters used 1.65 shots per deer killed, and hit each deer 1.3 times. All calibers of rifles used performed equally well. Low hunting efficiency would preclude the commercial harvesting in northern white-tailed deer ranges except in areas with accessible populations exceeding 10-25 deer per square mile. J. WILDL. MANAGE. 37(3):336-342 Two of the most practical indices for deer herd management are the number of deer which hunters see and shoot each year and the abundance and condition of the deer food plants. Other data such as reproductive rates, size, condition, density, distribution, and food habits provide interesting and sometimes useful information for planning deer herd management, but are of little immediate value until they are applied to the objectives of providing deer for the gun and protecting the vegetation from overutilization. The purpose of this paper is to show that the number of deer shot per hunter-hour, or hunting efficiency, is correlated with deer density. STUDY AREA AND DEER HERD A herd of approximately 300 white-tailed deer was present in 1967 on Griffith Island in Georgian Bay, Ontario. The island, approximately 2 miles offshore, comprised 2,600 acres of which 450 were fenced to exclude deer. Most of the island was covered with a hardwood forest which had been logged about 75-100 years previously, although some areas were cleared more recently. Most of the grass meadows, which occupied 20 percent of the deer range, were cleared and ploughed more than 30 years ago. Deer were introduced about 1919-22 for recreational hunting. Until 1968 the island was owned by Frigidaire Products of Canada Ltd. Pheasant and wild turkey shooting was provided in addition to the deer. The recorded annual harvest between 1954 and 1966 averaged 50 deer. Provision of corn and hay during the winter, absence of predators, absence of significant parasites and diseases (L. Karstad, personal communication), and the low harvest rate allowed the deer population to increase far beyond the carrying capacity of the range. Total depletion of available browse, and the lack of trees less than 30 years old suggested that an overpopulation had been present for many years. The deer were exclusively grazers, using open meadows in the evenings and early mornings (possibly all night) but not during the day when they fed on the grasses and forbs under the forest canopy. In 1967 many of the does were without fawns, and most of the does with fawns were thin. A few yearlings and bucks were also in poor condition. During the summers of 1966 and 1967 1 Financial support for this project was received from the Canadian National Sportsmen's Show and the National Research Council of Canada. The generous provision of transportation and living accommodation by Frigidaire Products of Canada Ltd. made this project possible. 336 J. Wildl. Manage. 37 (3):1973 This content downloaded from 207.46.13.158 on Tue, 15 Nov 2016 03:59:04 UTC All use subject to http://about.jstor.org/terms HUNTING EFFICIENCY AND DEER DENSITY o Holsworth 337 I spent 60 days on the island observing the diurnal behavior and distribution of the deer. The overbrowsed vegetation and the flat terrain provided ideal conditions for observing and I encountered about five groups of deer per hour during most of the day. Evening and roadside counts, from all roads, were made by the caretaker of the property. During most summer evenings in 1966 he counted 50-70 deer, and in 1967 he counted 70-110 deer. On the basis of my observation and the known harvest for the previous 15 years, I estimated the population in October to be 300 deer.