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Treesearch

Distribution and habitat of the western gray squirrel (Sciurus griseus) on Fort Lewis, Washington.

Informally Refereed
Download (PDF 355 KB): https://research.fs.usda.gov/download/treesearch/5536.pdf

Abstract

Sciurus griseus has been accorded a "threatened" status by the Washington Department of Wildlife. Our objectives were to determine the distribution, abundance, and factors limiting the abundance of Sciurus griseus on Fort Lewis. Between June 1992 and August 1993 we conducted walking surveys for squirrels in 169 oak-conifer stands (approximately 700 ha). We observed 38 individual squirrels in 30 of the stands. We compared occupancy of oak stands by size, distance to water, and vegetation characteristics. We found that oak stands used by squirrels generally were: 1) > 2.0 ha, 2) < 0.6 km from water (lake, marsh, stream, or river), 3) on average, 34% Quercus garryana, 53% Pseudotsuga menziesii, and 13% other tree species, and 4) diverse in food-producing trees and shrubs including Acer macrophvllum, Fraxinus latifolia. and Oemleria cerasiformis. Sciurus griseus is associated with Quercus garryana woodlands which are dwindling due to human development. Fort Lewis holds the largest publicly—managed area of Quercus garryana in the Puget Sound region. In order to protect Sciurus griseus populations we recommend: 1) informing the public about Sciurus griseus and its status to reduce squirrel deaths by automobiles and 2) conserving and actively managing oak woodlands.

Citation

Ryan, L.A.; Carey, A.B. 1995. Distribution and habitat of the western gray squirrel (Sciurus griseus) on Fort Lewis, Washington. Northwest Science. 69(3)