Chapter 14. Review of technical knowledge: Great gray owls

Abstract

The great gray owl (Strix nebulosa) is the longest, but not heaviest, of the northern forest owls. Distributed holarctically across the boreal forests of North America and Eurasia, the great gray owl extends its range southward into the contiguous states by inhabiting forests other than the boreal type. The subalpine and montane forests of the Cascade Range, Sierra Nevada Range, and the Rocky Mountains support great gray owl populations in central Washington; central and northwestern Oregon; north-central and eastern California; northern, central, and southeastern Idaho; western Montana; and northwestern Wyoming. Despite its large size, broad distribution, and relatively bold nature, the great gray owl remains poorly understood. European investigations focus primarily on how Microtus populations affect the owl's productivity and movements (Hilden and Helo 1981, Mikkola 1983, Stefansson 1983, Cramp 1985, Korpimaki 1986). We have found no studies that examine great gray owl poplation characteristics or habitat use. In North America, Bull et al. (1988a, 1988b, 1989a, 1989b) intensively studied great gray owl demography, movements, and habitat use. Their study area in northwestern Oregon, however, may not be characteristic of the entire North American range. Franklin (1988) observed the breeding biology of great gray owls in southeastern Idaho. Duncan (1992) examined great gray owl movements as they relate to several factors, including prey abundance, for a Canadian population. The remaining studies (e.g., Winter 1986, Osborne 1987, Spreyer 1987) are largely limited to describing nest sites. Though the great gray owl has not been targeted for expansive ecological studies, a useful body of knowledge has accumulated through more specific research and incidental sources.

Parent Publication

• Flammulated, boreal, and great gray owls in the United States: A technical conservation assessment

Citation

Duncan, James R.; Hayward, Patricia H. 1994. Chapter 14. Review of technical knowledge: Great gray owls. In: Hayward, G. D.; Verner, J., tech. editors. Flammulated, boreal, and great gray owls in the United States: A technical conservation assessment. Gen. Tech. Rep. RM-253. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. p. 159-175