'1 C.3 COYOTE CONTROL: A SIMULATION EVALUATION OF ALTERNATIVE STRATEGIES Russell L. Gum Louise M. Arthur Richard S. Magleby U.S. Department of Agriculture Economics, Statistics, and Cooperatives Service Agricultural Economic Report No. 408 COYOTE CONTROL: A SIMULATION EVALUATION OF ALTERNATIVE STRATEGIES, by Russell L. Gum, Louise M. Arthur^ and Richard S. Magleby. Natural Resource Economics Division, Economics. Statistics,.and Cooperatives Service, U.S. Department of Agriculture, Agricultural Economic Report No. 408- ABSTRACT Current and alternative coyote control strategies in the Western United States are evaluated via a computerized simulation model which predicts the economic and socio-environmental impacts of each strategy. A gradual decrease in lamb losses and an increase in net economic benefits are predicted if the 1974 level of coyote control. $7 million. is increased to $20 million. Socio-environmental benefits did not change significantly under that simulation. Beyond the $20 million level of expenditures, net economic benefits are predicted to decline slightly and socio-environmental benefits decline rapidly. At expenditures below 197^ levels, both economic and socio-environmental benefits decline substantially. Changes in mixes of control methods are discovered which permit both economic and socio-environmental benefits to increase. These alternatives include increased use of the M-44 and aerial gunning and decreased use of traps. Key words: Coyotes, Predator control. Sheep losses. Simulation, Environmental evaluation. ABOUT THE AUTHORS Russell L. Gum and Louise M. Arthur are, respectively, agricultural economist and social science research analyst. Natural Resource Economics Division, Economics, Statistics, and Cooperatives Service (ESCS), U.S. Department of Agriculture, stationed at the Department of Agricultural Economics, University of Arizona, Tucson. Richard S. Magleby is an ESCS agricultural economist in Washington, D.C. ACKNOWLEDGMENTS The authors appreciate the data and consultation from the U.S. Fish and Wildlife Service, U.S. Department of the Interior, and the helpful suggestions from W. E. Martin, University of Arizona, and the many other reviewers of this manuscript. Washington, D.C. 20250 July 1978 FOREWORD Ihig report presents results of a simulation evaluation of the economic, environmental, and social benefits and costs of present and alternative policies for control of coyotes in the Western United States, The simulation results depend heavily on hypotheses about relationships among coyote control, coyotes, sheep and larri) losses, and other environmental effects. These hypotheses and the analyses are based on the most reliable data available and on judgments of experts in coyote control. As more data become available, the hypotheses can be revised to describe the control situation more precisely. Meanwhile, this simulation is considered a reasonable approximation of me current situation, with the results providing valuable information for decisionmaking on the control issue. The research was conducted by the Economic Research Service, U.S. Department of Agriculture, in cooperation with State universities, at the direct request of Congress. On January 1. 1978 the Economic Research Service was merged with the Statistical Reporting Service and the Farmer Cooperative Service to form the Economics, Statistics, and Cooperatives Service. Special appropriations by Congress in fiscal years 1974 and 1975 funded the research. Other reports in the series focused on characteristics of the sheep industry, levels of sheep and lamb losses, reasons for the decline of sheep production in the West, and costs and returns of western sheep producers. CONTENTS Highlights ii Synopses of Other Reports in this Series ili Introduction 1 The Simulation Model 3 Function of Each Component of the Model 4 Use of the Model's Two Final Outputs 5 Socio-environmental Considerations 6 Economic Considerations 14 Simulation Results 15 Changing Only Expenditure Levels Ih Increasing Expenditures on Each Method in Turn l8 Changing Both Expenditures and Method Mix 18 Conclusions 20 Research Recommendations 22 References 23 Appendix A: Control Methods and 1974 Expenditures 25 Federal Control Efforts 25 Private Control Efforts 25 Total Control Efforts 3I Appendix B: Technical Aspects of the Simulation 33 Socio-environmental Evaluation Methodology 33 Cross Impact Simulation of Control/Coyote/Lamb Loss Relationships . 37 Impacts of Coyote Control on Other Wildlife 41 Economic Impact Evaluation Methodology 42 Appendix C: User's Guide to the Coyote Control Inforrration System .... 45 HIGHLIGHTS Coyote control programs in the Western United States involve Federal, State, and private expenditures on various control methods. Throu^ use of a computerized simulation model, predictions are made of the economic and SOCIO-environmental impacts of actual and alternative expenditure levels for these methods. Economic impacts represent those on producers of lambs and sheep, plus those on consumers of lamb and mutton. Socio-environmental impacts include public acceptability of methods (humaneness, selectivity, and cost effectiveness), coyote population changes, and impacts of coyotes on other wildlife. The computerized simulation model facilitates consideration of control alternatives by (1) making explicit the key relationships affecting the impacts of control, (2) permitting changes in the relationships to reflect the best data, judgment, and experience available, (3) rapidly calculating both economic and environmental impacts, and (4) presenting the results so that the impacts and impact tradeoffs of alternatives can be compared easily. However, the model and impacts reported here represent first approximations and should be used as supplements to judgment and experience. Key relationships in the model need validation and refinement as better data and analyses become available. According to the model, increases in expenditures from $7 million to $20 million on the same mix of controls would result in a decrease in coyote population levels, a gradual decrease in lamb losses (from 8 percent down to 4 percent), and a slight increase in net economic benefits. Overall socio-environmental benefits did not change significantly. Beyond the $20 million level of expenditures, net economic benefits would decline slightly and socio-environmental benefits would decline rapidly. At control levels below 1974 levels, both economic and socio-environmental benefits would decline substantially. Alternative mixes of control methods are found for which predicted economic and socio-environmental benefits increased. The mixes of control methods yielding the highest economic benefits included increased use of toxicants—presently limited by legal restrictions—and decreased use of trapping. Predicted socio-environmental benefits are enhanced by decreasing expenditures on trapping and increasing expenditures on the M-44 cyanide ejector and aerial gunning. Research needed to support decisionmaking on predator control should aim for better methods for (1; measuring and monitoring livestock losses on a continuing basis, (¿) predicting losses as a function of control, coyote population, and management practices, and (3) determining impacts on gams species. Additional needs include better data on coyote numbers and coyotes taken by sport hunting and fur trappers. 11 SYNOPSES OF OTHER REPORTS IN THIS SERIES "Characteristics of Sheep Production in the Western United States" by C. Kerry Gee and Richard S. Magleby Agricultural Economic Report No. 3^5. About 80 percent of the sheep in the United States are raised in the West, where extensive private and public ranges provide the bulk of the feed. Only about 41 percent of the West's sheep producers have commercial scale operations of 50 head or more, but they own nearly 93 percent of the region's sheep. About one-third of these commercial producers have specialized in sheep, v*iile two-thirds have diversified livestock operations. More than two-thirds operate as sole proprietors, while me rest have formed partnerships and family corporations. Many have substantial equity positions which indicate past profitability. About one-fifth will likely be retiring in the next 10 years, viiich could result in many operations going out of sheep Production. About half of the feed requirement for commercial sheep comes rom private range, while public range supplies one-fifth. Over half of the commercial sheep are grazed under tiie care of herders, usually on open range. Most lambing occurs in late winter and early spring. More commercial producers practice shed lambing than range lambing, but the number of sheep involved is less. The principal marketing problem is the few number of buyers bidding on lambs. "Sheep and Lamb Losses to Predators and Other Causes in the Western United States" by C. Kerry Gee, Richard Magleby, Warren R. Bailey, Russell L. Gum, and Louise M. Arthur Agricultural Economic Report No. 369 Predators, principally coyotes, are the major cause of lamb and sheep losses in the Western United States, according to 9,000 farmers and ranchers surveyed in 1974. Rates of loss to coyotes varied considerably amjng farmers and ranchers; vhile many had no or minor prédation problems, others reported very high losses. Overall, in the Western United States, losses attributed to coyotes in 197^ numbered 728,000 lambs (more than 8 percent of all lambs born) and 229,000 adult sheep (more than 2 percent of inventory), representing a third of