A White-Tailed Deer Harvesting Strategy

Abstract

We describe a harvest strategy that integrates a population dynamics model, a rationale for choosing a harvest rate, a means of implementing harvesting, and a change-in-ratio (CIR) population estimation technique. The size of the harvest is determined by selecting a proportion of the postharvest (residual) population (#) chosen between about zero and the intrinsic rate of increase in a given environment (rm), with a maximum sustained yield (MSY) at about 0 = r,/2 based on logistic growth, or about i = 0.5 based on McCullough's (1979:118, 1984) studies of the George Reserve white-tailed deer (Odocoileus virginianus) herd. The advantages of proportional harvesting are that the population stabilizes for all proportions, the location of the population along the sustained yield (SY) curve is unambiguous, and proportions are naturally self-correcting because harvests are tied to population size. Taking 2 separate single-type (sex) harvests provides a means for achieving the harvest quota and also yields a CIR population estimate based on observations of the proportion of antlered deer in the population at 3 times. The 2-stage CIR technique is robust to unequal observability, a major weakness of the traditional CIR methods. Our harvest strategy is most applicable where harvests can be controlled closely, and hunting seasons are relatively short. Field experiments are required to establish the efficacy of our harvest paradigm. J. WILDL. MANAGE. 52(4):589-595 Several components are needed to provide a framework for managing harvests of white-tailed deer to attain harvest and population goals. Among these are an underlying model of population dynamics that incorporates removals due to hunting, a rationale for choosing a harvest level, a means of implementing and controlling the removals, and a procedure to evaluate the success of the harvest strategy. Our objective is to integrate these requirements into a management paradigm based on a stock-recruitment model of population responses to harvesting (McCullough 1979:123-127, 1984), on 2 separate single-type (sex) removals during the hunting season, and on a 2-stage CIR population estimation technique (Pollock et al. 1985). We present a management paradigm, based on logic and theory that incorporates the concept of proportional harvesting. The 2-stage CIR is used to estimate population size, but any suitable estimation technique could be applied. We caution that our paradigm requires testing under field conditions. Our analysis begins with a deterministic model and then expands to consider briefly stochastic variability. Our strategy is most appropriate for herds closely controlled by managers. To support our rationale, we draw upon published literature and our experiences studying the deer herd on Remington Farms, Chestertown, Maryland. O r paradigm differs from the strategy developed by Hayne and Gwynn (1977), which uses the proportion of females in the harvest as a management objective. They reasoned that if th adult male harvest is inherently limited because hunter effort declines as males become scarce, then the female harvest could also be limited at a lower level by relating it to the male harvest. Their approach does not estimate population size or incorporate a measure of productivity, yet it has apparently been misinterpreted by some deer managers to reflect recruitment or changes in herd size (Downing 1981). Furthermore, Downing (1981) showed tha , alone, the proportion of females in the kill reveals little about the status of the herd. Our paradigm differs from Hayne and Gwynn's (1977) in that ours incorporates an estimate of the population and a measure of productivity. We thank Remington Farms and especially E. C. Soutiere and E. H. Galbreath for their encouragement and support. D. A. Adams, G. Caughley, P. D. Doerr, E. C. Franklin, and D. R. McCullough reviewed earlier drafts and provided helpful comments. This is paper 11498 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh. IPresent address: Florida Game and Fresh Water Fish Commission, Route 7, P.O. Box 440, Lake City, FL 32055.