Thesis
Conditioned Food Aversion with an Odor Cue to Reduce Bear Conflict and Crop Loss
Washington State University
Master of Science (MS), Washington State University
05/2025
DOI:
https://doi.org/10.7273/000007382
Abstract
Nutrient-dense and convenient foods in agricultural fields attract bears. Bear consumption of agricultural crops is an economic loss for farmers but a potentially important source of energy and nutrients for bears preparing to hibernate. Conditioned food aversion (CFA) is a form of behavior modification based on a temporary yet unpleasant physiological response like nausea resulting from ingesting adulterated food. CFA has been combined with other stimuli, such as an odor cue (CFAO), to strengthen the aversion. We hypothesized that CFAO could be effective in bears due to their reliance on olfaction and memory when foraging. We tested CFAO in captive brown bears at Washington State University using the aversive agent thiabendazole (TBZ) and an odor cue (lemon oil). Because aversion was retained even after two hibernation periods with stronger aversion in wild-born bears than captive-born bears, we developed a field test of CFAO. Bait stations containing TBZ-laced fruit sprayed with lemon oil were placed on the perimeter of a Washington orchard and monitored through the active season via trail cameras and site visits. Fruit abundance between rows of trees treated with lemon oil and untreated rows was monitored to assess the effectiveness of CFAO as a means of reducing crop loss. Bear visitations to the orchard declined over time, but we were unable to determine if that was due to treatment effects or other processes, such as increasing abundance of natural foods. There were no significant differences in fruit disappearance between treated and untreated trees earlier in the study. During the fall months, there was a significantly higher percentage of treated fruits remaining compared to untreated fruits, supporting CFAO’s effectiveness in reducing crop loss. However, the effect of the odor cue treatment declined significantly leading up to hibernation. Longer field trials over more locations in future research are the next steps to develop CFAO as a nonlethal management tool to reduce economic loss, bear-human conflict, and bear mortalities.
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Details
- Title
- Conditioned Food Aversion with an Odor Cue to Reduce Bear Conflict and Crop Loss
- Creators
- Heather L Havelock
- Contributors
- Heiko T Jansen (Chair)Charles T Robbins (Committee Member)Heather E Watts (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Biological Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 63
- Identifiers
- 99901220470001842
- Language
- English
- Resource Type
- Thesis