Biology and distribution of the Northern Spotted Owl

Ralph J Gutierrez

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


The Northern Spotted Owl is widespread in the Pacific Northwest, occurring in most forested portions of physiographic provinces within its range. It is strictly a forest dwelling species rarely venturing into open habitat unless it is dispersing. Structural features of forests used for roosting, nesting, and foraging are similar. All of these habitats have diverse vegetation structure. However, a broader range of habitats are used for foraging than are used for nesting and roosting. In addition, both disturbed (e.g., those previously logged or burned) and undisturbed (usually mature/old-growth conifer forests) habitats used by owls show strong structural similarity. In general, Spotted Owls select habitats with large trees and more complex structure than is available to them at a particular locality. Northern Spotted Owls are monogamous breeders with low fecundity and high survival rates. They are territorial and tend to form long-term pair bonds. Breeding occurs irregularly. Because of their specificity for certain kinds of habitat, low fecundity, long life span, and apparent negative response to fragmentation and habitat loss (Forsman et al. 1984, Forsman et al. 1988, Carey et al. 1992, Johnson 1992), it should not be surprising that this subspecies was a candidate for population decline following extensive habitat disturbance (Thomas et al. 1990, USDI 1990, 1992). The forests that the owl inhabits also contain extremely valuable timber (Simberloff 1987). This combination of factors has led to the Northern Spotted Owl being one of the most extensively and intensively studied birds in the world.

Original languageEnglish (US)
Pages (from-to)2-5
Number of pages4
Issue numberSUPPL. 17
StatePublished - Jan 1 1996


  • Northern Spotted Owl
  • Strix occidentalis caurina
  • behavior
  • diet
  • distribution
  • habitat use
  • home range
  • nesting
  • populations
  • reproduction


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