Proceedings of the Vertebrate Pest Conference

Iterative (1 variable-changed-at-a-time) Lotus 1-2-3® spreadsheet calculations were used to derive hypothetical benefit:cost ratios (BCRs) based on the recommended-use patterns for a commercial turf repellent (Rejex-It®) to deter Canada geese from grazing/loafing on golf fairways and for a commercial shrub/plant repellent (Deer I Repellent®) to deter deer from browsing on landscape shrubbery. Scenarios were based on “real-world” costs of products and valuations of resources. Plots of the BCR-response surfaces for Rejex-It® on fairways showed that BCRs for these turf applications ranged between 63.9 and 0.73. These BCRs showed transitivity, with highest to lowest BCRs linked with revenues from 90+ foursomes per day, 28-day spray intervals, 3.34 ha of fairways, and a $2.00/ha application cost versus 45+ foursomes/day, 7-day spray intervals, 10.24 ha of fairways, and a $10.00/ha application cost, respectively. A plot of BCRs for using Deer I Repellent® based on replacement outlays for shrubs yielded BCRs between 47.12 and 0.52. This response surface yielded transitivity within shrub-size/-number classes and had enhanced “scallop;” all BCRs for 6 and 12 spray applications involving 10-40 shrubs, 0.305-1.122-m radius plants, and 20-100% damage were ≥2.27 (i.e., more than double the cost outlays for the chemical). Although requiring a number of assumptions, our approach provides useful decision-making aids for persons interested in the economics of wildlife damage management methods. The main advantage is that projections of the combinations of variables associated with the potential “break-even” point (BCRs =1.0) for these interventions are available a priori, and that scenarios can be modified with relative ease to view the benefit-cost impacts of other input variables or model assumptions.