Effects of deterrents on avian abundance and nesting density in electricalsubstations in Oklahoma

Power outages caused by wildlife at electrical substations can be a major f inancial burden for utility companies and cooperatives. Snakes, presumably preying on nesting birds, have historically been the major cause of wildlif e-related outages at Western Farmers Electric Cooperative (WFEC) substation s. We studied avian abundance, diversity, and nesting density, and investig ated die efficacy of avian deterrents at 62 substations in the WFEC system in Oklahoma in 1996-97. Data from the first year of the study were consiste nt with this history nesting densities and bird abundance were higher at he avily damaged substations (greater than or equal to 0.3 incidents/yr) than moderately damaged or undamaged substations. Low-profile substations had mo re nests, higher bird abundance, and more damage than lattice-design substa tions. In the second year of the study, we tested 2 bird deterrents: electr onic distress calls (noisemakers) and sodium-iodide lights. Neither deterre nt was effective at reducing bird nesting or abundance, although noisemaker s slightly reduced bird numbers inside the substations relative to the cont rol. We do not recommend noisemakers or sodium iodide light arrays as bird deterrents at electrical substations.