Spotted Owl Research Program

May 24, 2011

After two decades of research and management and policy changes, it is likely that new regulations will be promulgated for protecting Northern Spotted Owls. Such changes are anticipated as the 2008 Spotted Owl Recovery Plan is revised, and from new science on competitive interactions with barred owls.

There is heightened environmental concern about Northern Spotted Owls, because spotted owl populations are declining rapidly in Washington, and the regulatory arena has become unstable. Mapped locations of owl nesting sites on private lands no longer can be “de-certified” after multiple surveys of non-detections because the presence of barred owls reduces spotted owl responses to surveys.

New survey protocol has been drafted, but it needs to be tested for accuracy in areas where spotted owls are known to be present by virtue of being radio-tagged. Wildlife biologists continue to speculate that habitat loss on private timberlands is partly responsible for the population declines, which could lead to new litigation and/or costly new requirements for private protection of sites occupied (or perhaps re-occupied in the future) by spotted owls.

NCASI supports multiple field research projects initiated to clarify survey methods, determine spotted owl responses to uneven-aged forest management, and evaluate spotted and barred owl responses to vegetation composition and structure from Washington through western Oregon and northern California.

By spring 2010, NCASI had collected radio telemetry data on more than 265 spotted owls and approximately 50 barred owls, resulting in the largest database ever acquired. Several research papers have been published.

NCASI continues to provide field and database support for multiple studies and technical input:

  1. Completion of study of “Adaptive Management for Northern Spotted Owls and California Spotted Owls”. Small-scale examinations of habitat selection relative to forest-patch conditions in 10 study areas, including two recently initiated studies in northern California.
  2. Estimate vocal and movement responses of spotted owls to new survey procedures in areas occupied by barred owls—“piggy-back” upon radio-tracking studies: Eastern WA Cascades; Southwestern WA; Springfield, OR; Redwood National Park; and BLM Headwaters Reserve, CA.
  3. Habitat selection by northern barred owls, southwestern WA, western Oregon. Develop resource selection models based upon radio-tracking data and vegetation sampling at small scales.
  4. Conduct vegetation sampling using variable-radius procedures that allow links with forest-growth models and company inventory databases.
  5. Modeling space-use patterns of spotted owls:  estimate factors influencing size and distribution of radio-telemetry locations of spotted owls relative to physical environmental features and vegetation conditions.
  6. New modeling being conducted by federal agency scientists will spawn technical-input efforts that will assist agencies in management activities and in informing policy-makers.