California Spotted OwlCalifornia Spotted Owl

Population Ecology of Northern Spotted Owls in Northwestern California

Principal Investigator: Alan Franklin
Project Start Date: 04/01/00
Expected Completion Date: Ongoing project
Funding Agency: University of Minnesota, USFS

Introduction: This project is a continuation of a long-term mark-recapture study of northern spotted owls in northwestern California, which began in 1985. This study is anticipated continuing until 2010. Numerous past publications have resulted from this study and the results from this study have been used extensively to guide management of northern spotted owl populations in the Pacific Northwest.

Objectives: To estimate age-specific demographic parameters, understand factors affecting those parameters, and elucidate mechanisms responsible for variation in population dynamics of northern spotted owls in northwestern California.

Progress: In addition to meeting the above objectives (see Franklin et al. 2004 below), two additional studies were implemented as pilot studies: (1) the role of ecotones as sources of prey for northern spotted owls - this work builds on previous research from this study that implicated ecotones as important determinants of habitat quality for northern spotted owls. We examined movements of prey from high density/low availability areas into older forest using multi-strata capture-recapture models coupled with distance sampling estimators and radio-telemetry; and (2) The role of past wildfire regimes in determining habitat quality in spotted owl territories – this work began examining pre-settlement fire histories on landscapes currently used by spotted owls to relate the effects of mixed-severity fire on landscape and stand structure on habitat quality in spotted owl territories.

Results/Products:
One publication, 3 technical reports, and 4 presentations resulted from this project during the period April 10, 2004 to April 10, 2005.

Franklin, A. B. 2005. Habitat quality in northern spotted owls in northwestern California: implications for management. Workshop for federal scientists and biologists on the science of the northern spotted owl; U.S. Fish and Wildlife Service; Portland, Oregon.

Franklin, A. B. 2005. Northern spotted owl research: information needs for future management. Workshop for federal scientists and biologists on the science of the northern spotted owl; U.S. Fish and Wildlife Service; Portland, Oregon.

Franklin, A. B. 2004. Habitat quality in northern spotted owls in northwest California. Public Hearing of the Scientific Review Panel for the Northern Spotted Owl, Sustainable Ecosystem Institute, Portland, Oregon.

Franklin, A. B. 2004. Information needs for the northern spotted owl. Public Hearing of the Scientific Review Panel for the Northern Spotted Owl, Sustainable Ecosystem Institute, Portland, Oregon.

Franklin, A. B., R. J. Gutiérrez, J. D. Nichols, M. E. Seamans, G.C. White, G. S. Zimmerman, J. E. Hines, T. E. Munton, W. S. LaHaye, J. A. Blakesley, G. N. Steger, B. R. Noon, D. W. H. Shaw, J. J. Keane, T. L. McDonald, and S. Britting. 2004. Population dynamics of the California spotted owl (Strix occidentalis occidentalis): a meta-analysis. Ornithological Monographs, 54:1-55.

Ganey, J. L., G. C. White, D. C. Bowden, and A. B. Franklin. 2004. Evaluating methods for monitoring populations of Mexican spotted owls: a case study.Pages 337-385 In: W. L. Thompson, editor. Sampling Rare or Elusive Species: Concepts, Designs and Techniques for Estimating Population Parameters. Island Press. Washington, D.C.

Lukacs, P., A. B. Franklin, and D. R. Anderson. 2004. Passive approaches to detection in distance sampling. Pages 260-280 In: S.T. Buckland, D.R. Anderson, K.P. Burnham, J.L Laake, D.L. Borchers and L. Thomas, editors. Advanced distance sampling. Oxford University Press, Oxford, Great Britain.

Anthony, R. G., E. D. Forsman, A. B. Franklin, D. R. Anderson, K. P. Burnham, G. C. White, C. J. Schwarz, J. Nichols, J. Hines, G. S. Olson, S. H. Ackers, S. Andrews, B. L. Biswell, P. C. Carlson, L. V. Diller, K. M. Dugger, K. E. Fehring, T. L. Fleming, R. P. Gerhardt, S. A. Gremel, R. J. Gutiérrez, P. Happe, D. R. Herter, J. M. Higley, R. B. Horn, L. L. Irwin, P. J. Loschl, J. A. Redi, and S. G. Sovern. 2004. Status and trends in demography of northern spotted owls. Report to Interagency Regional Monitoring Program, USDA Forest Service, Portland, Oregon.

Franklin, A. B., R. J. Gutiérrez, P. C. Carlson, and D. Pavlacky. 2004. Population ecology of the northern spotted owl (Strix occidentalis caurina) in northwestern California: annual results, 2003. U. S. Forest Service, Region 5, San Francisco, California. 18pp.

Courtney, S. P., J. A. Blakesley, R. E. Bigley, M. L. Cody, J. P. Dumbacher, R. C. Fleischer, A. B. Franklin, J. F. Franklin, R. J. Gutiérrez, J. M. Marzluff, and L. Sztukowski. 2004. Scientific evaluation of the status of the northern spotted owl. Sustainable Ecosystems Institute, Portland,
Oregon. 508 pp.