Wildfire and endangered species management are paramount priorities for Sierra Nevada land managers today. More than a century of logging and fire exclusion in some mixed-conifer stands has led to declines of old-forest dependent species and a build-up of small-diameter fuels. This build-up has been blamed for increases in size and severity of wildfires in these forest types. The Spotted Owl (Strix occidentalis) has been identified as an indicator species for the health of old-forest ecosystems because it is strongly associated with older forests for nesting, roosting, and foraging. Stand-replacement fire is often invoked as one of the primary threats to the species, but results from research investigating the impacts of fire on Spotted Owls are equivocal. Research was urgently needed to answer questions about how Spotted Owls respond to habitat conditions caused by wildfire, so that post-fire landscapes can be best managed to benefit this focal species.

Above: A parent and juvenile Spotted Owl near their nest in a burned area of of our study site.

In 2006 project investigators Monica Bond, Derek Lee, Rodney Siegel, and Pat Ward initiated a project to radio-track 7 adult male and female California Spotted Owls throughout the breeding and non-breeding season in territories that were burned by a large wildfire four years earlier in the southern Sierra Nevada. We sought to determine whether the owls preferentially use or avoid habitat burned at varying severities for foraging and roosting during the breeding season--important information for post-fire management that will benefit the species.

We also estimated daytime roost locations of 5 of the radio-tagged California Spotted Owls during the non-breeding season, to determine whether these owls enlarged or shifted their breeding ranges, or migrated to new areas, and whether they roosted in burned landscapes. Movements and habitat requirements of the California Spotted Owl during the non-breeding season remain poorly understood in comparison with the breeding season, and ours are the first data on fall and winter habitat use in burned landscapes.

Another component of this project was examining whether breeding-season diet and home-range size of California Spotted Owls differed between our burned study site and other unburned study sites in the Sierra Nevada. We collected and analyzed regurgitated pellets at roosting locations in our burned site to quantify the diet of owls whose territories were affected by forest fire.

Above: Derek Lee and Monica Bond analyze Spotted Owl pellets to determine diets of owls nesting in burned landscapes.

Published papers resulting from this project include:

Bond, M. L. D. E. Lee, R. B. Siegel, and J. P. Ward. 2009. Habitat use and selection by California Spotted Owls in a postfire landscape. Journal of Wildlife Management 73:1116-1124. Download

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. Download

In early 2007 we were invited to present preliminary results to the Northern Spotted Owl Federal Recovery Team. In September 2009, co-PI Monica Bond was appointed to the dry-forest landscape workgroup, a team of technical experts whose role is to inform the Northern Spotted Owl Recovery Plan Implementation Team on issues relating to fire impacts on the subspecies. We also presented our results at the Wildlife Society 2009 Annual Meeting in Monterey, California. You can view the PowerPoint presentation here, but be advised it is a large file.

2. Habitat Modeling, Field Census and Development of Management Plans for Northern Spotted Owls in North Cascades National Park, WA

IBP scientists are collaborating with NPS Wildlife Biologist Bob Kuntz at North Cascades National Park, WA, to census Spotted Owls throughout the Park, and to develop management tools for them, including a habitat suitability map, and site-specific management plans for each Spotted Owl breeding site. Contact Rodney Siegel for more information.

Above: Spotted Owl survey crew leader Micah Scholer above one of our study areas in North Cascades National Park.