1. Status Review for the Northern Spotted Owl (Strix occidentalis caurina) in California Carie Battistone and Neil Clipperton Senior Environmental Scientists CDFW, Wildlife Branch April14, 2016

2. Species Description Medium-sized dark brown owl with white spots on head, neck, back, and underparts Dark brown, almost black, eyes surrounded by prominent facial disks CDFW Photo © Culpepper

3. Range Range divided into 12 provinces, 3 of which are in California o California Coast o California Klamath o California Cascades

4. California Range

5. Prey Flying squirrels (Glaucomys sabrinus) and woodrats (Neotoma sp.) are primary component of diet throughout most of the range. Flying squirrels are main component in North (much of Washington and Oregon) Woodrats are the main component in the southern portion of the range (California and parts of Oregon) Woodrat, Santiago Oaks Regional Park, CA © Laura Cohen Northern Flying Squirrel © Bob Cherry

6. Habitat Nesting and Roosting Foraging Dispersal (not discussed here) USFWS Photo

7. Habitat Nesting and Roosting Generally, nesting and roosting habitat includes: o multilayered, multispecies canopy dominated by large conifers (>30 inches dbh) o well-developed understory of conifers or hardwoods o high canopy closure (60-80 %) o Large coniferous trees with deformities, (cavities, broken tops, dwarf mistletoe infections) o large snags o accumulations of ground litter (logs and other woody debris) Spies and Franklin 1988

8. Habitat Foraging Foraging habitat encompasses a wider range of stand composition and structure than nesting- roosting habitat Composed of variable-aged conifer stands and a more diverse set of forest types (e.g., hardwood forests) and structural characteristics: o old forest similar to nesting and roosting habitat o younger forests o hardwood stands o open areas with shrub habitat or woody debris o edge habitat

9. Status and Trends Abundance No range-wide population estimate exists Pre-harvest surveys have dramatically increased knowledge on location of territorial owl sites (i.e., activity centers) Densities vary across the range and forest types o extrapolating the few local estimates across the range of the subspecies would result in biased estimates of abundance Northern Spotted Owl with young. USFWS Photo

10. Status and Trends Abundance As survey effort has increased over time, so has the number of known activity centers o 3,116 as of 2014 Activity centers do not necessarily reflect current abundance or density

11. Status and Trends Demographic Study Areas 11 study areas across the range cover 9% of the owl range 3 areas in California o Northwestern California (federal land) o Green Diamond (private timber land) o Hoopa (tribal land)

12. Status and Trends Demographic Trends Study AreaFecunditySurvival Territory Occupancy Population Change % Population Change over time NWC -55% HUP -32% GDR -9% to -41% CAS (OR) No trend -44%

13. Status and Trends Demographic Trends

14. Status and Trends Occupancy Declines in occupancy observed at all 11 study areas since the 1990s In California, occupancy rates declined from: 79% to 47% at the NWC 74% to 38% at the HUP 92% to 55% at the GDR In southern Oregon occupancy rates declined from 69% to 44%

15. Farber and Kroll (2012) Status and Trends Occupancy Interior study area showed occupancy declines around 40% for both pairs and single owls

16. Status and Trends Habitat Effects Spotted Owls benefit from a mosaic of forest types containing sufficient old growth around the core, interspersed with younger or other vegetation types. No more than about 50% of home range should consist of nonhabitat. Figure from http://woodlot.novascotia.ca/book/export/html/24

17. Status and Trends Habitat Effects Spotted Owl fitness is maximized in territories that have a large amount of older forests, but that are intermixed with significant amounts of earlier succession vegetation types. Franklin et al. 2000

18. Existing Management 14.3 million acres of forested lands within the Northern Spotted Owl range in California 6.4 million acres are publicly owned (45%) 7.8 million acres are privately owned (55%)

19. Existing Management Federal lands largely governed by the Northwest Forest Plan Nonfederal lands must comply with the Forest Practice Rules for commercial timber harvest.

20. Threats Habitat Loss o Timber harvest (conifer and hardwood) and regulatory mechanisms o Wildfire and salvage logging o Climate Change – forest composition and structure o Sudden Oak Death o Marijuana cultivation Population status declines Barred Owl Disease Climate Change – weather patterns Contaminants Predation Recreational Activity Loss of Genetic Variation USFWS Photo

21. Threats Habitat Loss – timber harvest Since 1993 (the development of a reserve system under the NWFP), timber harvest on federal land has declined. Conversely, timber harvest has been the primary cause of habitat loss on nonfederal lands USFWS Photo Loss due to harvest on federal land (acres) Loss due to harvest on federal and nonfederal land (acres) CA Coast 20079,500 CA Klamath 10,40050,100 CA Cascade 7,20044,700 Total 17,800174,300

22. Threats Habitat Loss – timber harvest USFWS Photo The minimum habitat retention requirements of owl habitat do not appear to be sufficient at negating impacts to owls in all cases. interior activity centercoastal activity center

23. Threats Habitat Loss - Wildfire Wildfire suitability modeling compared to actual fire map USFWS Photo

24. Threats Habitat Loss - Wildfire Most loss occurred on federal land in the California Klamath Province. USFWS Photo Federal Lands Loss due to Wildfire on federal land (acres) Loss due to Wildfire on federal and nonfederal land (acres) CA Coast 1,8005,600 CA Klamath 199,800208,100 CA Cascade 7,20010,500 Total 208,800224,200

25. Threats Habitat Loss - Wildfire Conditions that support more frequent, large, and more severe fires are projected to increase due to climate change. Habitat loss due to wildfires will likely continue. USFWS Photo Davis et al. 2011

26. Threats Barred Owl Native to eastern North America Expanded into western North America Occur throughout the range of the Northern Spotted Owl. USFWS Photo Livezey 2009

27. Threats Barred Owl Today, nearly 2,000 Barred Owl records exist within the Department’s species database. USFWS Photo

28. Threats Barred Owl Documented impacts from Barred Owls include  altered behavior of Spotted Owls (e.g., reduced calling),  displacement of Spotted Owls from preferred high quality habitat,  decreased survival and occupancy rates, and  increased territory extinction rates USFWS Photo

29. Threats Barred Owl USFWS Photo Mendocino Redwood Company 2014 Annual Report Humboldt Redwood Company 2014 Annual Report Hoopa 2013 Report Dugger et al. 2016 – CA study areas

30. Threats Barred Owl USFWS Photo Diller et al. 2016 Results indicate that removal appears to be successful at mitigating the negative impact to Spotted Owls and are feasible at least at a local- scale.

31. Conclusion There are steep and accelerating declines in NSO population and vital rates Primary threats to the continued existence of NSO in California are: o rapid expansion the Barred Owl into the range of the NSO o rapid and accelerating decline in population size and vital rates o loss of habitat due to wildfire and timber harvest These coupled with other threats (climate change, impacts of marijuana cultivation, disease, Sudden Oak Death) will lead to additional declines unless additional management intervention is undertaken.

32. Recommendation The best scientific information available indicates to the Department that the petitioned action is warranted, and the Department recommends to the Commission that the Northern Spotted Owl be listed as Threatened under the California Endangered Species Act.

33. Questions? © Robert Hawkins