In this study I investigated population changes in the deermouse (Peromyscus maniculatus) in the southwestern part of the Morice Forest District of the Prince Rupert Forest Region of British Columbia. I tested the hypothesis that synthetic weasel odours would adversely affect deer mouse population parameters. In July, 1991, three areas were treated with weasel odour and in September, 1991 three additional areas were treated. The same areas were treated in July and September of 1992.
Densities of deer mice were not found to be significantly different between treated and control areas. However, on average, numbers of deer mice were lower on treated areas following the July treatments of 1991 and 1992. Survival rates appeared to be lower and more erratic on treated than control areas in 1991; however, there were no statistically significant differences. Reproduction appeared to be unaffected by the odours. I concluded that deer mice did not display a behavioural response, as manifested by population parameters, to weasel odours. I speculated that decreases in densities were owing to predation by weasels which were attracted to the odours on treated sites. I also concluded that the use of weasel odours as a biological control method for voles (Microtus spp.) would likely have little impact on deer mice (a non-target species). Community stability would be maintained with this relatively species-specific biological control method.Forestry, Faculty ofGraduat
