Northern Spotted Owl
Federally Threatened, Marin population appears stable
Late-succession and old-growth forest of Douglas-fir, coast redwood, bishop pine, mixed conifer–hardwood, and other evergreen hardwood trees
Cause of range-wide decline:
Loss of habitat in late-successional and old-growth forest; competition with Barred Owls as this close relative expands its range
Current primary threats in Marin County:
Competition from the Barred Owl, poisoning from rodenticides, habitat loss
What we’re doing about it:
We are researching Northern Spotted Owls in Marin County to understand the biology of a secretive species living in close proximity to an urban center where noise and human traffic can impact the owl. Our current research project addresses these human threats by locating and monitoring nests and promptly communicating these results to local land managers. USFWS rules require that land management activities do not harm or harass owls or their habitat.
Our data have resulted in:
- better placement of new trails
- timing of road and trail maintenance activities (mowing and grading) around nesting season,
- seasonal closure of shooting ranges near nesting owls,
- preservation of individual nest trees, and surrounding habitat
- Determination of owl activity centers to help with responsible placement of housing sites.
- Our habitat analysis has broadened concept of "potential habitat" locally and expanded where protections are applied.
Visit The State of the Birds San Francisco Bay 2011 and reading the reports and publications below.
Status and distribution of the barred owl in Marin County, California , Jennings, S., R. L. Cormier, T. Gardali, D. Press, and W. W. Merkle. 2011. Western Birds 42: 103-110.
Status and trends in demography of Northern Spotted Owls, 1985–2003. Wildlife Monographs No.163. Anthony et.al.
Modeling nest-site occurrence for the Northern Spotted Owl at its southern range limit in central California. Landscape and Urban Planning 90: 76-85. Stralberg et. al.
How you can help:
Visit The State of the Birds San Francisco Bay 2011 to view threats and conservation actions for the Northern Spotted Owl.