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Oregon Field Station Damage Research

photo of pocket gopher

Physical Barriers

Field station personnel are working to identify new nonlethal tools and to evaluate and improve existing technologies. Physical deterrents are effective if they are constructed to completely impede access by offending wildlife. However, construction and maintenance are often cost prohibitive. Efforts are underway to identify less expensive materials and possibly reduced labor costs. Studies also are being conducted to improve our understanding of how materials used to construct barriers affect animals (e.g., attraction) and plants (e.g., microclimate), along with necessary strength, size, and configuration for effective physical barriers.

Frightening Devices and Operating Systems

Technology has provided a multitude of frightening devices and operating systems (e.g., acoustics, visuals, detection devices). Scientists are working to understand wildlife species responses to varied delivery intervals, paired consequences, and varied responses depending on status (i.e., male vs. female, dominant vs. submissive, individuals vs. groups). In addition, the station routinely evaluates efficacy of commercial repellents to deter deer browsing. Scientists continue to evaluate natural products (e..g., plant extracts, predator odors) to assess their potential as active ingredients in repellents. The field station recently completed a series of studies evaluating efficacy of an alternative feeding program to reduce tree girdling by bears, and assessing possible impacts on nutritional status and behavior of bears using feeding stations.


Developing nonlethal means to alleviate damage, requires a thorough understanding of the underlying mechanisms governing foraging behavior. Although, much basic information exists to describe foraging in a few model species (e.g., rat, sheep), little data have been collected for wildlife. Moreover, there is limited understanding of the factors that determine the effectiveness of most management strategies, including environmental context, forage and site selection by wildlife, and variables influencing animal movements and dispersal. All too often, this limited understanding leads to the failure of management plans to achieve their intended objectives.

Several studies conducted at the Olympia field station have explored the roles that experience and the chemical senses play in the foraging behaviors of various species. For example, a series of studies determined criteria used by black bears to select trees for girdling, and then related these criteria to silvicultural practices. Other ongoing studies are elucidating deer foraging response to active ingredients used in repellents. Scientists working at the station are trying to determine what role secondary metabolites (e.g., terpenes), contained in most conifers, have on wildlife foraging. A series of studies is investigating whether prior experience may cause animals to be more tolerant of metabolites, and thus more likely to browse seedlings. Other studies seek to determine whether foraging preferences exhibited by deer among western red cedar genotypes is correlated with terpene concentrations. Scientists also are investigating whether nutritional status of deer affect their ability to cope with secondary metabolites.


Scientists also are assessing potential baits to reduce rodent populations because non-lethal tools are not always feasible, such as when wildlife populations exceed the capacity of available foraging resources. Thus the most effective, yet humane and environmentally safe, products need to be identified.

Mammalian Damage in Forested and Riparian Ecosystems Research Project
Mountain Beaver Damage and Management
Bear Damage and Management
Pocket Gopher Damage and Management
Deer and Elk Damage and Management
Porcupines, Voles, Rabbits, Hares, Pikas





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