Behavioral Responses of Yellowstone Ecosystem Grizzly Bears to Applications of Aversive Conditioning Techniques

Authors(s): C. L. Hunt, F. M. Hammond and C. M. Peterson

Publication:

Publisher:

Publication Date: 0000-00-00

Type: Progress Report

Location: Cody WY

Abstract: Grizzly bear mortality from management control actions has become a significant proportion of overall grizzly deaths in the Greater Yellowstone Ecosystem and elsewhere. Traditional methods to resolve conflicts do not prevent problems from recurring and bears that are repeat offenders eventually are removed or destroyed. This report deals with the second year of a planned three-year WGF study. The objective of this study was to develop techniques and evaluate the effectiveness of a potential aversive conditiioning agent in keeping grizzly bears away from sites of human habitation and/or anthropogenic food sources. Trials were conducted on radio-instrumented, problem grizzly bears in the Yellowstone Ecosystem. A simple within-subjects design, using subject-as-own control with counterbalancing during the testing phase, was attempted during the second year of the study in 1987. Each subject (S) was to receive conditioning with an unconditioned aversive stimulus (US) in the presence of one of two similar, but different, randomly assigned conditioned stimuli (CS). Following this treatment , all Ss were to be tested for the effects of learned aversion by means of presenting the CS in one trial and a neutral one in another trial. Order of presentation was counterbalanced to control for bias. The US was a 02-grain plastic bottle filled with 30 ccs of water, traveling with 299.7 F.P.E., and fired from a modified Model 267 Smith & Wesson Gas and Flare Gun. During 1986 two subadult and one adult (with two cubs-of-the-year) female grizzly bears were shot at eight times and hit six times at eight specific problem sites. During 1987 two adult female grizzly bears (one with two yearlings) were shot at four times and hit three times at four roadside sites. When hit, all bears immediately ran from the site, often leaving the general area. No aggressive responses were displayed. After being hit, bears that were causing problems at specific sites would generally not reenter the site while the researchers were there; often they did not return to the site for two to four weeks regardless of the researchers' presence. Bears hit while forging along the roadsides did not return to the specific sites where they were hit and generally reduced their foraging immediately adjacent to the roadsides; they also ceased using roadways as travel routes and began crossing roadways at a run. Trapping and relocation efforts may have affected the responses of these bears. Results thus far are encouraging, but are based on both a small number of Ss and only one sex is represented, and, especially with respect to the testing phase, the data is limited. Both Ss were presented with a trial apiece of the CS, but with equivocal results. The possible effects of food availability and social pressures on bear responses to aversive conditioning are discussed. During 1986 and 1987 conditioning efforts were limited by the low number of candidate bears available. This situation was addressed during 1987; study methods were revised and interagency cooperation improved. Therefore, given the availability of problem bears in 1988, a larger number should be considered as candidates.

Keywords: animal, behavior, mammal, bear, Ursidae, grizzly bear, Ursus arctos horribilis, human activity, mortality, radio collar, food, Greater Yellowstone Ecosystem