Cooperative Fish and Wildlife Research Units Program: Oregon
Education, Research and Technical Assistance for Managing Our Natural Resources

Oregon Project

Intra-guild predator dynamics: the effects of recolonizing gray wolf populations on cougars in northeast Oregon.

October 2013 - June 2019


Participating Agencies

  • Oregon Department of Fish and Wildlife
  • ODFW

Since the reintroduction of wolves in Idaho, Montana, and Wyoming in 1996, recovering wolf populations have expanded their distributions into Oregon, and other western states where they have largely be extirpated (since 1940's in Oregon). Consistent wolf sign was observed in northeastern Oregon in 2006 and now 8-10 packs exist in this region. Since near extirpation of cougars in Oregon in the 1960's, cougar populations have now recovered to stable levels throughout the state and their ecology and population dynamics prior to the arrival of wolves is well studied. The recolonization of wolves into Oregon raises important questions regarding their impacts on prey populations (deer and elk), livestock depredation, and interspecific competition with cougars.

Within this context, we will address the following objectives:
1) Determine prey selection of wolves in multiple packs in Oregon where prey availability differs among packs.
2) Determine effects of presence of wolf pack(s) on population dynamics and habitat use of cougars in the Mt. Emily Wildlife Management Unit.
3) Evaluate factors which may influence elk and deer populations in a mixed carnivore system with wolves.

Theses and Dissertations Publication Date
Orning, Elizabeth K. 2019. Carnivore competition: spatial and dietary implications of gray wolf recolonization for cougars in northeast Oregon. Ph.D. Dissertation, Oregon State University, Corvallis, Oregon. 242 pp. June 2019
Bailey, O.A. 2018. Extrinsic and intrinsic factors associated with reproductive success of Caspian Terns (Hydroprogne caspia) at East Sand Island, Columbia River estuary. M.S. thesis, Oregon State University, Corvallis, Oregon. 142 pp. September 2018