Contact Information: 

Dr. Jimmy Taylor 

Supervisory Research Wildlife Biologist 

Oregon State University

321 Richardson Hall

3180 SW Jefferson Way

Corvallis, OR 97331

Phone: (541) 737-1353 

FAX: (541) 737-1393

jimmy.d.taylor@aphis.usda.gov

www.aphis.usda.gov/wildlife_damage/

nwrc/ 

Major Cooperators

 British Columbia Ministry of Forests 

and Range

 Mississippi State University

 Oregon Forest Industries Council

 Oregon Department of Forestry

 Oregon Department of Fisheries and 

Wildlife 

 Oregon State University

 Portland State University

 The Jack Berryman Institute

 USDA Forest Service 

 U.S. Department of Defense

 Washington Forest Protection 

Association

 Washington Department of Fisheries 

and Wildlife 

 Washington Department of Natural 

Resources

Wildlife Services

Protecting People rotecting People

Protecting Agriculture rotecting Agriculture

Protecting Wildlife rotecting Wildlife

FY 2012

National Wildlife Research Center

United States Department of Agriculture

Animal and Plant Health Inspection Service

National Wildlife Research Center Scientists Develop Methods to Reduce 

Timber Damage

Wildlife Services’ (WS) National Wildlife Research Center (NWRC) is the only Federal 

research facility devoted exclusively to resolving confl icts between people and wildlife 

through the development of effective, selective, and socially responsible methods, tools, 

and techniques. NWRC’s expertise in Corvallis, Oregon, focuses primarily on wildlife 

damage to forest resources.

Wildlife impacts on regenerating forests following wildfi re or harvesting can be extensive. 

Cutting and gnawing on seedlings by deer, elk, mice, mountain beavers, pocket gophers, 

rabbits, and voles during the fi rst 5 years of tree growth greatly hinder reforestation efforts. 

Other mammals such as bears and porcupines damage mature trees. North American 

beaver and nutria alter riparian vegetation, which limits streamside restoration efforts, 

erodes roads and railways and can endanger human health and safety. NWRC scientists 

are developing nonlethal tools and methods (e.g., repellents and habitat and behavior 

modifi cation) to manage wildlife damage to forest resources.

Applying Science and Expertise to Wildlife Challenges

Testing Tools to Protect Forest Resources—Use of commercial repellents and 

frightening devices are of interest to land managers as non-lethal options to reduce browse 

damage by deer. However, research has shown that repellents can be cost prohibitive 

and often provide little to only short-term protection. Deer also habituate quickly to 

frightening devices. Cost-effective and longer lasting tools are needed for application in 

forest management. NWRC scientists recently evaluated the effects of two commercial 

products used to repel deer in western Oregon. When used during the spring to protect 

young Douglas fi r seedlings during leader growth, individuals treated with Seadust 

Wildlife ControllantTM experienced less browse damage than untreated seedlings. Future 

evaluations will determine if protection lasts through critical wintering periods without 

reapplication. NWRC scientists also evaluated the effi cacy of a bioacoustic device, Deer 

Shield® Pro, in repelling black-tailed deer from residential urban areas. Results suggest 

that preexisting habituation to humans limits the effect of the device; however, new studies 

are underway to evaluate Deer Shield Pro in early successional forest patches where 

deer cause damage to seedlings. Future research will address the cost-benefi ts of utilizing 

commercial products such as these in forest operations.

Understanding Tree Chemistry and Dietary Behaviors—Many human-wildlife confl icts 

are the result of animal foraging behavior and activity. NWRC researchers are discovering 

how wildlife species respond to select chemicals in the plants they eat. Initial results 

suggested that when given a choice, black-tailed deer prefer to eat conifer seedlings 

with low terpene levels. Terpenes are found in the essential oils of plants. They have a 

strong smell and may thus protect the plant from browsing animals. Further research 

demonstrated that seedling age also can infl uence animal foraging behavior. Current 

studies are evaluating the effi cacy of selecting for these traits and deploying them in an 

integrated management design to reduce deer browse in reforestation efforts.

Mountain Beaver Genetics—Mountain beaver are endemic to the Pacifi c Coast of 

California, Oregon, Washington, and British Columbia, Canada, and to the Sierra Nevada 

Mountains of California, and Nevada. There are seven subspecies of mountain beaver. 

The U.S. Department of the Interior’s Fish and Wildlife Service has classifi ed one of these 

subspecies, Aplodontia rufa nigra, as endangered and several other mountain beaver 

subspecies as populations of concern under the Endangered Species Act. However, in 

some portions of its range (Washington and Oregon), mountain beaver cause signifi cant 

Reducing Mammalian Damage in educing Mammalian Damage in 

Forested and Riparian Ecosystems orested and Riparian Ecosystems

Groups Affected By These Problems

 Commercial timber producers

 Gardeners/Landscapers

 Homeowners

 Natural resource managers

 Noncommercial forest landowners

 Orchard managers

 State departments of transportation
damage to forest resources and are managed as a “pest” 

species. Studies of mountain beaver populations are critical 

for understanding their status and informing wildlife damage 

management practices. Molecular genetics techniques are 

particularly useful for explaining taxonomic relationships and 

population demographics. NWRC scientists have recently 

completed a molecular taxonomic study of this species and 

discovered that mountain beaver found in Washington are a 

single subspecies when it was previously considered two distinct 

subspecies. Furthermore, scientists confi rmed the uniqueness of 

the coastal California subspecies including the endangered 

A. r. nigra and the species of concern, A. r. phaea. To aid 

research efforts related to mountain beavers, NWRC scientists 

developed DNA markers from the A. r. rufa genome. These 

markers provide a new and powerful tool for studying A. r. rufa

populations. A current study is using these DNA markers to test 

whether mountain beaver move across forested landscapes to 

new areas where forest harvesting operations create optimal 

habitat. 

Better Understanding of Beaver Ecology—North American 

beaver are found throughout the continent and are commonly 

referred to as ecosystem engineers because they modify habitat 

through dam building. Research has shown that beaver dams 

increase local biodiversity; however, dams also cause fl ooding 

and alterations to stream fl ow that result in crop damage, fl ooded 

timber,and habitat destruction. More research is needed to 

better understand the impacts of beaver ecology. In the Pacifi c 

Northwest, beaver dams provide important habitat for threatened 

and endangered anadromous fi shes such as Mid-Columbia 

River steelhead and coho salmon. Collaborative efforts with 

researchers at Oregon State University are using spatial analyses 

to evaluate how beaver respond to anthropogenic activities used 

to improve fi sh habitat. At Mississippi State University, another 

collaborative study is evaluating beaver movement on a military 

installation that has experienced high beaver damage to forest 

resources. Study results suggest that beaver home range sizes 

increased with increasing plant biomass and proportions of 

woody plant cover. Additionally, the speed of beaver movements 

increases as they move further away from the safety of their 

lodges, particularly during the breeding season. 

Selected Publications:

CARRILLO, C. D., D. L. BERGMAN, J. TAYLOR, D. NOLTE, P. 

VIEHOEVER, and M. DISNEY. 2009. An overview of historical 

beaver management in Arizona. Proceedings of the Wildlife 

Damage Management Conference 13:216-224.

FIELD, K. L., A. A. BACHMANOV, J. A. MENNELLA, G. K. 

BEAUCHAMP, and B. A. KIMBALL. 2009. Protein hydrolysates 

are avoided by herbivores but not by omnivores in two-choice 

preference tests. PLoS ONE Jan 2009. (www.plosone.org) 

doi:20.1371/journal.pone.0004126.

KIMBALL, B. A. and J. D. TAYLOR II. 2010. Mammalian 

herbivore repellents: tools for altering plant palatability. Outlooks 

on Pest Management 21:181-187.

KIMBALL, B. A. and K. R. PERRY. 2009. Evaluating new protein 

sources for development of a deer repellent product. Crop 

Protection 28:364-366.

KIMBALL, B. A., F. PFUND, M. GOURLEY, D. L. GRIFFIN, and 

J. H. RUSSELL. 2011. Silvicultural attempts to induce browse 

resistance in conifer seedlings. International Journal of Forestry 

Research. Article ID 108529.

KIMBALL, B. A., J. TAYLOR, K. R. PERRY, and C. CAPELLI. 

2009. Deer responses to repellent stimuli. Journal of Chemical 

Ecology 35:1461-1470.

PIAGGIO, A. J., M. A. NEUBAUM, H. YUEH, C. E. RITLAND, 

J. J. JOHNSTON, and S. L. PERKINS. 2009. Development of 

10 polymorphic microsatellite loci isolated from the mountain 

beaver, Aplodontia rufa rufa (Rafi nesque). Molecular Ecology 

Resources 9:323-325.

TAYLOR, J. 2011. Identifying and managing for wildlife 

damage during stand initiation. Northwest Woodlands, Winter 

Edition 2011:16-17, 29.

TAYLOR II, J. D., D. L. BERGMAN, and D. L. NOLTE. 

2009. An overview of the International Beaver Ecology and 

Management Workshop. Proceedings of the Wildlife Damage 

Management Conference 13:225-234.

The U.S. Department of Agriculture is an equal opportunity employment provider and employer

Major Research Accomplishments:

 WS is evaluating the effectiveness of commercial 

products, such as repellents and scare devices, to 

reduce deer damage.

 WS is working to determine if conifer seedlings 

selected for heritable traits such as known 

monoterpene profi les can be used to reduce 

browsing by deer.

 WS used molecular genetic techniques to redefi ne 

the taxonomic profi les of mountain beaver 

subspecies where they cause damage to forest 

resources.

 WS is using spatial analyses to reduce negative 

and increase positive impacts of beaver damming 

behavior.