Evaluation of Harvest Strategies for a Simulated Wild Turkey Population

Abstract

A model was developed to analyze the long-term effect of the addition of a spring gobbler hunt on the dynamics of a hypothetical population of eastern wild turkeys (Meleagris gallopavo silvestris) already subjected to a fall hunt of either sex. The random variables-the total annual mortality rate, the hunting mortality rate, and the immature:adult female reproduction ratio-were assumed to be normally distributed and to vary independently and randomly witin a range of three standard deviaffons either side of the mean while the simulated population reacted to the random changes in these variables for each year of the 100-year simulation period. Ite total annual mortality was assumed to fluctuate randomly within the range of 60 + 1S percent; the immature:adult female reproducfion ratio fluctuated randomly within the range of 3.025 + 0.75 young per adult female. All random variables were assumed to be independent of popuIation size. Ite fall harvest was assumed to be part of, not additive te, the total annual mortality and to fluctuate randomly within a range of as + 15 percent. The spIing harvest of all xexually active (2 years or older) males was assumed to be additive to the total annual mortality; thus, the effect of the spring hunt was analyzed at its upper limit. The analysis suggests that when the reproductive attainment is adequate to ensure a self-sustaining population, liberalized spring hunting of gobblers is biologically innocuous, regardless of ie short-term upward or downward trends of the population. The establishment of biologically sound and socially acceptable harvest regulations is a recurring problem facing all game management agencies. The long-term optimum use of a wildlife resource often is constrained by sportsmen's mores and agency conservatism. Both frequently result from a lack of information as to the impact of hunting mortality on the dynamics of game populations. The acceptance by sE>ortsmen of harvest regulations that enable game populations to be utilized more completely depends upon the wildlife agency's ability to present to sportsmen convincing population data. Thus, the capability of a game management agency to identify and assess the impact of alternative procedures for utilizaXon of wildlife populafions is of prime importance in attaining optimum utilization of our wildlife resources. lRelease No. 714 of the V;rginia Gooperative Wildlife Research Unit ( Virginia Commission of Game and Inland Fisheries Bureau of Sport Fisheries and Wildlife Wildlife Management Inst;te, and Virginia Polytechnic Insfftute and State University, cooperating). Through population simulation, long-term effects of alternative harvest strategies can be evaluated. Also, inconsistencies in available data become apparent, deficiencies of current information are pinpointed, and research needs are identified. Thus, a feedback mechanism is provided for administrators who must deade between several alternatives of harvest and research possibilities. Highly complex models with many variables, traditionally intractable, may be examined with relative ease and in a short period of time. Simulation models of management procedures are limited by the assumptions employed, so the validity of the assumptions utilized in any population model should be given careful considera-