Cooperative Research Units
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The demography of Northern Spotted Owls in Oregon and Washington

Duration

April 2010 - December 2020

Narrative

The Northern Spotted Owl (Strix occidentalis caurina) is listed as Threatened under the Endangered Species Act, primarily because of the loss of old growth forest habitat due to timber harvest. The Northwest Forest Plan was developed in the mid-1990's to conserve the owl and other old growth species, while allowing greatly reduced levels of commercial timber harvest on federal land. The Plan required the implementation of a regional effectiveness monitoring program for the spotted owl. This research project collects and analyzes data from 6 of the 8 spotted owl effectiveness monitoring program study areas across the owl's range. Data from this work is used to regularly evaluate population trends of spotted owls, as well as increase our understanding of owl ecology, including dispersal, diet, nest site selection, behavior, genetics, and response to a recent, congeneric invader, the Barred Owl (Strix varia).

Research Products and Activities

Peer Reviewed Publications

  • Dugger, KM, FF Wagner, RG Anthony, GS Olson. 2005. The relationship between habitat characteristics and demographic performance of Northern Spotted Owls in southern Oregon. Condor 107:865-880.
  • Olson, GS, RG Anthony, ED Forsman, SH Ackers, PJ Loschl, JA Reid, KM Dugger, EM Glenn, and WJ Ripple. 2005. Modeling of site occupancy dynamics of northern spotted owls in Oregon, including the effects of barred owl encroachment. Journal of Wildlife Management 69:918-932.
  • Anthony, RG, ED Forsman, AB Franklin, DR Anderson, KP Burnham, GC White, CJ Schwarz, JD Nichols, JE Hines, GS Olson, SH Ackers, S Andrews, BL Biswell, PC Carlson, LV Diller, KM Dugger, KE Fehring, TL Fleming, RP Gerhardt, SA Gremel, RJ Gutiérrez, PJ Happe, DR Herter, JM Higley, RB Horn, LL Irwin, PJ Loschl, JA Reid, SS Sovern. 2006. Status and trends in demography of Northern Spotted Owls, 1985-2003. Wildlife Monographs 163:1-47.
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Technical Publications

  • Anthony, RG, FF Wagner, K Dugger, and G Olson. 2002. Identification and evaluation of northern spotted owl habitat in managed forests of southwestern Oregon and the development of silvicultural systems for managing such habitat: Report on Step 2: Analysis of habitat characteristics and owl demography on three density study areas. Oregon Cooperative Fish and Wildlife Research Unit, Corvallis, OR.
  • Anthony, RG, ED Forsman, AB Franklin, DR Anderson, KP Burnham, GC White, CJ Schwarz, JD Nichols, JE Hines, GS Olson, SH Ackers, S Andrews, BL Biswell, PC Carlson, LV Diller, KM Dugger, KE Fehring, TL Fleming, RP Gerhardt, SA Gremel, RJ Gutiérrez, PJ Happe, DR Herter, JM Higley, RB Horn, LL Irwin, PJ Loschl, JA Reid, SS Sovern. 2004. Status and trends in demography of Northern Spotted Owls, 1985-2003. Final Report to Interagency Regional Monitoring Program, Portland, OR (peer-reviewed by 4 ESA members). Oregon Cooperative Fish and Wildlife Research Unit, Corvallis, OR.
  • Dugger, KM, F Wagner, and RG Anthony. 2005. Identification and evaluation of northern spotted owl habitat in managed forests of southwestern Oregon and the development of silvicultural systems for managing such habitat. Report on Step 3: Predicting northern spotted owl survival and reproductive success from habitat characteristics of managed forests of southwestern Oregon. Oregon Cooperative Fish and Wildlife Research Unit, Corvallis, OR.
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Thesis

  • Schilling, J.W. 2009. Demography, Home Range, and Habitat Selection of Northern Spotted Owls in the Ashland Watershed. M.S. Thesis, Oregon State University, Corvallis, OR. 129pp.

Presentations

  • Dugger, KM, F Wagner, R Anthony, & G Olson. 2003. The identification and evaluation of northern spotted owl habitat in relation to their demographic performance in managed forests of southwestern Oregon. Oregon Chapter of The Wildlife Society Conference, Eugene, OR, February 2003.
  • Dugger, KM, F Wagner, R Anthony, & G Olson. 2004. The identification and evaluation of northern spotted owl habitat in relation to their demographic performance in managed forests of southwestern Oregon. Public Meeting of the SEI Northern Spotted Owl Status Review, Vancouver, WA, March 5, 2004.
  • Olson, GS, RG Anthony, ED Forsman, SH Ackers, PJ Loschl, JA Reid, KM Dugger, EM Glenn, and WJ Ripple. 2004. Modeling of site occupancy dynamics of northern spotted owls in Oregon, including the effects of barred owl encroachment. The Wildlife Society Annual Conference, Calgary, AB, Canada, September 20, 2004.
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Current Staff

Federal Staff: 4

Masters Students: 12

Phd Students: 11

Post Docs: 3

University Staff: 16

5 Year Summary

Students graduated: 20

Scientific Publications: 71

Presentations: 268

 

Personnel

  • Katie DuggerPrincipal Investigator
  • Robert AnthonyCo-Principal Investigator
  • Jason W SchillingStudent
  • Chad Marks-FifeStudent

Funding Agencies

  • Pacific Northwest Research Station
  • USDA Forest Service

Links

Oregon Cooperative Fish and Wildlife Research Unit Cooperators

  1. Oregon Department of Fish and Wildlife
  2. Oregon State University
  3. U.S. Fish and Wildlife Service
  4. U.S. Geological Survey
  5. Wildlife Management Institute