The INSTITUTE for BIRD POPULATIONS
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CONSERVING SIERRA NEVADA BIRDS OF PREY
Northern Goshawk photo
California Spotted Owl. Photo by Jacob Bourque
Birds of prey, including owls and other raptors like hawks and falcons, face many of the same threats as other Sierra Nevada birds, including habitat loss, climate change, pollution, and changing fire patterns that can greatly alter habitat. However, several of the region’s bird of prey may be particularly vulnerable due to their high position on the food web, need for large expanses of habitat, and reliance on charactaristics of old forests – like large trees and closed canopies – that can take decades or centuries to develop fully after disturbance.
IBP scientists collaborate with federal, state, and private land managers to study and conserve Sierra Nevada populations of birds of prey, including Spotted Owl, Great Gray Owl, and Northern Goshawk. Our work advances the understanding of the ecology, conservation status, and habitat needs of these species, particularly in relation to forest management, climate change, and the effects of fire. We use our own findings, as well those of other scientists, to develop practical, science-based strategies land managers can implement to conserve the birds.
Banner photo of Northern Goshawk by Martha de Jong-Lantink/Flickr. Great Gray Owl illustration by Lynn Schofield.
CONSERVATION STRATEGY
IBP partnered with the California Department of Fish and Wildlife and the broader California Partners in Flight community to develop A Conservation Strategy for Great Gray Owls in California. The Strategy synthesizes information from the scientific literature and interviews with 23 experts, and provides over 50 conservation recommendations that offer the best chance of preventing the extirpation of this species in California and increasing the population.
Great Gray Owl. Photo by Gregory Slobirdr Smith/Flicker.
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SELECTED PUBLICATIONS
Peer-reviewed Publications
Blakey, R.V., R.B. Siegel, E.B. Webb, C.P. Dillingham, M. Johnson, and D.C. Kesler. 2019. Multi-scale habitat selection by Northern Goshawks (Accipiter gentilis) in a fire-prone forest. Biological Conservation. doi.org/10.1016/j.biocon.2019.108348. (For a copy of this publication, please contact Rodney Siegel.)
Blakey, R.V., R.B. Siegel, E.B. Webb, C.P. Dillingham, R.L. Bauer, M. Johnson, and D.C. Kesler. 2019. Space use, forays, and habitat selection by California Spotted Owls (Strix occidentalis occidentalis) during the breeding season: new insights from high resolution GPS tracking. Forest Ecology and Management 432:912–922. (For a copy of this publication, please contact Rodney Siegel.)
Siegel, R.B., S.A. Eyes, M.W. Tingley, J.X. Wu, S.L. Stock, J.R. Medley, R.S. Kalinowski, A. Casas, M. Lima-Baumbach, and A.C. Rich. 2019. Short-term resilience of Great Gray Owls to a megafire in California, USA. The Condor: Ornithological Applications 121:1–13. (For a copy of this publication, please contact Rodney Siegel.)
Siegel, R.B., P. Pyle, and H.L. Loffland. 2018. Molt sequences in an extralimital Great Gray Owl detected over two winters in northwestern California. Western Birds 49:62–73. PDF
Polasik, J.S., J.X. Wu, K. Roberts, and R.B. Siegel. 2016. Great Gray Owls nesting in atypical, low-elevation habitat in the Sierra Nevada, California. The Journal of Raptor Research 50:194-206. (For a copy of this publication, please contact Rodney Siegel.)
Wu, J.X., R.B. Siegel, H.L. Loffland, M.W. Tingley, S.L. Stock, K.N. Roberts, J.J. Keane, J.R. Medley, R. Bridgman, and C. Stermer. 2015. Diversity of nest sites and nesting habitats used by Great Gray Owls in California. The Journal of Wildlife Management 79:937-947. (For a copy of this publication, please contact Helen Loffland.)
Bond, M.L., D.E. Lee, R.B. Siegel, and M.W. Tingley. 2013. Diet and home range size of California Spotted Owls in a burned forest. Western Birds 44:114-126. PDF
Lee, D.E., M.L. Bond, and R.B. Siegel. 2012. Dynamics of breeding-season site occupancy of the California Spotted Owl in burned forests. The Condor 114:792-802. PDF
Bond, M.L. D.E. Lee, R.B. Siegel, and J.P. Ward. 2010. Habitat use and selection by California Spotted Owls in a post-fire landscape. The Journal of Wildlife Management 73:1116-1124. PDF
Bond, M.L., D.E. Lee, and R.B. Siegel. 2010. Winter movements by California Spotted Owls in a burned landscape. Western Birds 41:174-180. PDF
Other Publications and Reports
Wu, J.X., H.L. Loffland, R.B. Siegel, C. Stermer. 2016. A Conservation Strategy for Great Gray Owls (Strix nebulosa) in California. Interim version 1.0. The Institute for Bird Populations and California Partners in Flight. Point Reyes Station, California. PDF
Schofield, L.N., R.B. Siegel, J.X. Wu, and R.L. Wilkerson. 2015. Avian monitoring in the King Fire: surveying Spotted Owls and Northern Goshawks during the 2015 breeding season. Report to the US Forest Service, Eldorado National Forest. The Institute for Bird Populations, Point Reyes Station, CA.
Siegel R.B., R.C. Kuntz II, R.L. Wilkerson, K.D. Kuhlman, and M.D. Toshack. 2012. Surveying for Spotted Owls in the Upper Skagit watershed of North Cascades National Park Complex, 2009-2010. Natural Resource Technical Report. NPS/NOCA/NRTR—2012/597. National Park Service. Fort Collins, CO. Published Report-2186188. PDF
Siegel, R.B, R.C. Kuntz II, R.L. Wilkerson, and K.D. Kuhlman. 2010. Surveying for Spotted Owls in the northeastern portion of North Cascades National Park Service Complex, 2009-2010: report for the 2009 field season. Natural Resource Technical Report NPS/NCCN/NRTR/2010/334. National Park Service, Fort Collins, CO. PDF
Siegel, R.B., K.E. Jablonski, M.N. Scholer, R.C. Kuntz II, and R.L. Wilkerson. 2008. Surveying Spotted Owls on the east slope of North Cascades National Park Service Complex: report for the 2007 and 2008 field seasons. Report to North Cascades National Park Service Complex. Natural Resource Technical Report NPS/NCCN/NRTR—2008/114. National Park Service, Fort Collins, CO. PDF
Wilkerson, R.L., and R.B. Siegel. 2007. Interpreting the Northwest Forest Plan’s Northern Spotted Owl habitat suitability model for use in North Cascades National Park. Report to North Cascades National Park Service Complex. The Institute for Bird Populations, Point Reyes Station, CA.
Siegel, R.B. 2006. Surveying for Great Gray Owl on the Carson and Bridgeport Ranger Districts of the Humboldt-Toiyabe National Forest during the 2006 breeding season. Report to U.S.D.A. Forest Service Pacific Southwest Region. The Institute for Bird Populations, Point Reyes Station, CA.
Siegel, R.B. 2002. Surveying Great Gray Owls at Sierra Nevada sites outside the greater Yosemite area: results from the 2002 field season. Report to Region 5 of the U.S.D.A. Forest Service. The Institute for Bird Populations, Point Reyes Station, CA.
Siegel, R.B. 2001. Surveying Great Gray Owls on southern Sierra Nevada forests: results from the 2001 field season. Report to U.S.D.A. Forest Service Pacific Southwest Region. The Institute for Bird Populations, Point Reyes Station, CA.