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Winter distribution and conservation status of the Sierra Nevada great gray owl

Authors

  • Eric P. B. Jepsen,

    1. Wildlife and Ecology Unit, Veterinary Genetics Laboratory, One Shields Avenue, University of California, Davis, CA 95616, USA
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  • John J. Keane,

    1. Pacific Southwest Research Station, USDA Forest Service, 1731 Research Park Drive, Davis, CA 95616, USA
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  • Holly B. Ernest

    Corresponding author
    1. Wildlife and Ecology Unit, Veterinary Genetics Laboratory, University of California, Davis, CA 95616, USA
    2. Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
    Current affiliation:
    1. 258 CCAH, Wildlife Population Health & Genetics, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, CA 95616, USA.
    • Wildlife and Ecology Unit, Veterinary Genetics Laboratory, University of California, Davis, CA 95616, USA.
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  • Associate Editor: Marc Bechard.

Abstract

Little information is available on the winter ecology of the small, geographically isolated, genetically-unique population of great gray owls (Strix nebulosa) in the central Sierra Nevada, California. This population is comprised of facultative, elevational winter migrants and access to winter habitat is an important component of their ecology. Winter observations and remotely sensed habitat variables were used to inform a predictive model of the environmental requirements and geographic distribution of this owl population. Using the modeled distribution map we assessed the distribution of 20% probability of occurrence classes relative to owl habitat associations, ownership, current development, and projected future development patterns. Our findings indicate that high probability class (81–100%) areas and the broader joint medium/medium-high/high probability class (41–100%) areas are uncommon on the landscape (0.2% and 5.0% of study area, respectively). High probability areas were characterized by Sierran Yellow Pine forest surrounding relatively small, flat areas of grassland, wet meadow, and riparian habitats, within the mid-elevation range. Approximately 32% of the high probability areas and 48% of the medium/medium-high/high probability areas occur on private lands. Of the areas on private lands, 32% of the high probability and 42% of the medium/medium-high/high probability areas occur on currently developed lands. Projected future development on private lands indicated that an additional 12% of the high and 18% of medium/medium-high/high suitability areas are slated for development by the year 2040. Future conservation planning efforts for the great gray owl in the Sierra Nevada will need to address management issues on both public and private lands. For future planning of development projects around great gray owl wintering habitat, the results from our study supplement current knowledge of breeding distributions to provide land and wildlife managers guidance on conservation priorities. © 2011 The Wildlife Society.

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