An Evaluation of Conditioned Taste Aversion to Deter Nest Predators: A Non-lethal Approach

Traditionally, reducing game-bird nest depredation has involved lethal means of predator control. We evaluated a non-lethal alternative, conditioned taste aversion (CTA), in Tom Green County, Texas. Simulated nests were constructed and baited with 3 eggs injected with lithium chloride, an aversive chemical. Simulated nests were constructed along the perimeter of a 40-ha pasture. A 21-day treatment phase was conducted with depredated nests being rebaited daily with treated eggs. A 28-day posttreatment phase involved establishing 24 non-treated nests in both the treated pasture and a control pasture. The study was replicated over 2 sites: the Management, Instruction, and Research Center (MIRC) and Stone Ranch (SR). There was no difference in nest survival between treatment and control pastures at MIRC (F = 5.0; 1, 3 df; P = 0.1). At SR, nest survival was higher in the treated pasture (F = 11.64; 1, 3 dfi P = 0.03). Principal nest predator species differed between sites and may have caused the variable results. Raccoons (Procyon lotor) accounted for 83% of the depredated nests at MIRC, while turkey vultures (Carthartes aura) accounted for 92% of the depredated nests at SR. These preliminary results suggest that CTA may be achieved for some predator communities. The feasibility of using CTA to deter nest predators may be affected by extent of area to be treated, chemical toxicity, and predator movements.

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