E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Strix occidentalis (Xantus De Vesey, 1860)
Spotted Owl
Family: Strigidae

Photo of species

© Shawn Hilton  Email the photographer   (Photo ID #5601)

E-Fauna BC Static Map
Distribution of Strix occidentalis in British Columbia
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Spotted Owl in British Columbia

by Shawn Hilton, Keystone Wildlife Research Ltd.


Northern Spotted Owls are a medium-sized owl, approximately 45-48 centimetres long, weighing 490-850 grams with females being slightly larger than males (COSEWIC 2008). Adult weights may fluctuate during the year, especially during the breeding season when food is prioritized for newly hatched young.

Adults are dark brown with a barred tail, white spots on the head and breast and facial disks. The eyes are dark brown. Juvenile and sub-adult owls look very similar to adults once downy feathers are dropped, but can still be distinguished by tail feathers: on young owls the tail feathers are pointed with white tips, while on adults they are rounded and mottled (COSEWIC 2008).

Spotted Owls are often confused with Barred Owls (Strix varia), and the two occasionally hybridize (Gutierrez 1996).



Nesting habitat for the Spotted Owl is typically old-growth forests with coarse woody debris, snags and a high canopy cover. Spotted Owls do not build their own nests but rely on naturally formed platforms (e.g., mistletoe infestations, snag tops, large stick nests constructed by other species), or cavities within large trees (Spotted Owl Best Management Practices Working Group 2009). Some sites are used by different owls over multiple generations (S. Hilton, pers. obs.).

Spotted Owls may not breed every year (Chutter et al. 2004); although there is observed high nest-site fidelity where territorial owls revisit annually, regardless if breeding occurs. When breeding does occur only one brood is produced, which typically comes from one or two eggs laid. The number of eggs laid and young fledged is likely linked to prey availability (Gutierrez 1996).


The Spotted Owl is considered a prey specialist, although preferred prey species may vary geographically. Analysis of pellets from Spotted Owls in the Chilliwack and Squamish Forest Districts showed that northern flying squirrels (Glaucomys sabrinus) comprised 43% of the diet, bushy-tailed woodrats (Neotoma cinerea) made up 13.4% of diet, and deer mice (Peromyscus maniculatus) made up 12.9% of the diet (composition by number; Horoupian et al., unpublished report, 1998). Analysis of pellets from two sites in the Lillooet Forest District (one nest site, one roost site) showed that bushy-tailed woodrats were the most common prey item (67.4% of diet by number), with deer mice the second-most common prey item (11.6% of diet by number); remains of flying squirrels were not found in any pellets (n = 35 pellets; Hilton & Hilton 2002). In the United States, an analysis of Spotted Owl diets showed that flying squirrels were a big component of diet in owls occurring from Washington to central Oregon, and shifted towards dusky-footed woodrats (Neotoma fucipes) and voles in southwestern Oregon and northwestern California (Thomas et al. 1990).


The Northern Spotted Owl is strongly associated with old growth forest structure throughout its entire range in North America (Forsman et al. 1984; Carey 1989; Ganey & Balda 1989; Carey et al. 1990, 1992; Solis & Gutierrez 1990; Bart & Forsman 1992; Mills et al. 1993). Spotted Owls appear to show preference for forests with Douglas-fir as the leading tree species, high canopy closure; complex vertical canopy layering; presence of many large wildlife trees; and volumes of coarse woody debris that can be in excess of 268 m3 per hectare (Solis & Gutierrez 1990; Mills et al. 1993; Spotted Owl Management Plan 1999). These habitat characteristics provide thermal cover, protection from predators, forage for prey species, nesting trees, and roosting areas for Spotted Owls (Spotted Owl Management Plan 1999).

In B.C., Spotted Owls are located in coastal, interior, and transitional (coastal-interior) ecosystems, and it is possible that habitat preferences vary slightly between the three areas. Spotted Owl habitat in B.C. has been divided into different categories and differ by biogeoclimatic subzone. As stated in the Spotted Owl Management Plan (1999):

"Superior habitat type for wetter, maritime ecotypes (CWHdm, CWHvm1, CWHvm2, and MHmm1) entails: 1) canopy closure in the range of 60-85% with 3 or more canopy layers; 2) a multi-species canopy (with preference for Douglas-fir and western hemlock) dominated by trees >50 cm dbh (with half of the stand >75 cm dbh); 3) a stand density of 150-250 stems per hectare; 4) 10 or more large trees (>75cm dbh) per ha with deformities; 5). >250 m3 per ha Coarse Woody Debris (CWD), most of which should be longer than 5 m and have a diameter of greater than 50 cm, and 6) at least 25% of the patchy understory should be shrubs."

Spotted Owl pairs have high site fidelity (Forsman et al. 1984). Home range sizes vary throughout the Pacific Northwest, from 606 +/- 302 ha (Carey et al. 1990) to 11,052 ha (Lehmkuhl & Raphael 1993) for a single Spotted Owl pair. In BC, radio-telemetry on 3 Spotted Owl pairs in the Squamish Forest District (1999 – 2001) revealed pair home ranges of 1700 to 4600 ha (mean = 3100 ha; Blackburn and Godwin 2003). Management of Spotted Owls in B.C. is based on an annual pair home range size of 3200 hectares, which is incorporated into land management objectives (Spotted Owl Management Plan 1999).

Global Distribution

The Spotted Owl is found from southwestern British Columbia through to Mexico.

British Columbia Distribution

The Northern Spotted Owl population in B.C. is at the periphery of the species’ range, and is sparsely distributed throughout old growth forests in southwestern British Columbia. The species occurs throughout the Chilliwack, Squamish and Cascades Forest Districts. There have been historical sightings in the Sunshine Coast Forest District (Campbell & Campbell 1984) but few surveys have been conducted in the District to confirm continued presence. Spotted Owls in British Columbia have been found to reside primarily from sea level up to an elevation of 1400 m.


From 1992 to 2002 there was a decline of up to 67% in the BC Spotted Owl population (Chutter et al. 2004). There are estimated to be fewer than 25 Spotted Owls left in BC (Spotted Owl Population Enhancement Team (SOPET) 2007).


There are three recognized subspecies of Spotted Owl in North America.

1) Mexican Spotted Owl (Strix occidentalis lucida) is east of the Cascade ranges in the Midwest
2) California Spotted Owl (Strix. occidentalis occidentalis) is only in California, from south of San Francisco Bay through to almost the Mexican border
3) Northern Spotted Owl (Strix occidentalis caurina) is found from southwestern British Columbia through to San Francisco Bay (COSEWIC 2008).

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
NativeS1RedE (Mar 2008)
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Range and Status Information Links

Additional Photo Sources

Species References

Bart, J., and E. D. Forsman. 1992. Dependence of northern spotted owls Strix occidentalis caurina on old-growth forests in the western USA. Biological Conservation 62:95–100.

Blackburn, I. And S. Godwin. 2003. The Status of the Northern Spotted Owl (Strix occidentalis caurina) in British Columbia. Draft report for BC Ministry of Water, Land and Air Protection. Surrey, BC.

Campbell, E. C., and R. W. Campbell. 1984. Status report on the Spotted Owl in Canada. 1983. COSEWIC, Ottawa.

Carey, A. B. 1989. Wildlife associated with old-growth forests in the Pacific Northwest. Natural Areas Journal 9:151–162.

Carey, A. B., S. P. Horton, and B. L. Biswell. 1992. Northern Spotted Owls: influence of prey base and landscape character. Ecological Monographs 62:223–250.

Carey, A. B., J. A. Reid, and S. P. Horton. 1990. Spotted Owl home range and habitat use in southern Oregon Coast Ranges. Journal of Wildlife Management 54:11–17.

Chutter, M. J., I. Blackburn, D. Bonin, J. Buchanan, B. Costanzo, D. Cunnington, A. Harestad, D. Heppner, L. Kiss, J. Surgenor, W. Wall, L. Waterhouse, and L. Williams. 2004. Recovery Strategy for the Northern Spotted Owl Strix occidentalis caurina in British Columbia. Page 74. Prep for BC Ministry of Environment. Retrieved from http://www.sararegistry.gc.ca/virtual_sara/files/plans/rs_spotted_owl_caurina_1006_e.pdf.

COSEWIC. 2008. COSEWIC Assessment and Update Status Report on the Spotted Owl Strix occidentalis caurina Caurina subspecies, in Canada.Committee on the Status of Endangered Wildlife in Canada, Ottawa, ON. Page vii + 48.

Forsman, E. D., C. E. Meslow, and H. M. Wight. 1984. Distribution and biology of the Spotted Owl in Oregon. Journal of Wildlife Management 48:3–64.

Ganey, J. L., and R. P. Balda. 1989. Home-range characteristics of Spotted Owls in northern Arizona. Journal of Wildlife Management53:1159–1165.

Gutierrez, R. J. 1996. Biology and distribution of the Northern Spotted Owl. Studies in Avian Biology 17:2–5.

Hilton, A., and S. Hilton. 2002. Inventory of Northern Spotted Owls: Lillooet Forest District. Page 109. Ministry of Water, Land and Air Protection, Kamloops, BC.

Horoupian, N., C.B. Lenihan, A. Harestad and I.R. Blackburn. 2000. Diet of Northern Spotted Owls in British Columbia. Unpublished report. Simon Fraser University, B.C.

Lehmkuhl, J. F., and M. G. Raphael. 1993. Habitat pattern around Northern Spotted Owl locations on the Olympic Peninsula, Washington. Journal of Wildlife Management 57:302–315.

Mills, L. S., R. J. Fredrickson, and B. B. Moorehead. 1993. Characteristics of old-growth forests associated with northern Spotted Owls in Olympic National Park. Journal of Wildlife Management 57:315–321.

Solis, D. M., and R. J. Gutierrez. 1990. Summer habitat ecology of Northern Spotted Owls in northwestern California. Condor 92:739–748.

Spotted Owl Best Management Practices Working Group. 2009. Best Management Practices for Managing Spotted Owl Habitat. Ministry of Environment and Ministry of Forests and Range.

Spotted Owl Management Plan. May 1999. Ministry of Environment Lands and Parks.

Spotted Owl Population Enhancement Team (SOPET). 2007. Northern Spotted Owl Population Enhancement and Recovery in British Columbia. Prepared for Government of BC, . Retrieved from http://www.env.gov.bc.ca/wld/speciesconservation/so/files/SOPET_Proposed_5year_Action_Plan_20070330.pdf.

Thomas, J. W., E. D. Forsman, J. B. Lint, E. C. Meslow, B. R. Noon, and J. Verner. 1990. A Conservation Strategy for the Northern Spotted Owl. U.S. Department of Agriculture, Forest Service, and U.S. Department of Interior, Bureau of Land Management, Fish and Wildlife Service, and National Parks Service, Portland Oregon. 427 pages.

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2023-10-02 2:03:08 PM]
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