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BC Conservation Data Centre: Species Summary


Strix varia
Barred Owl


 
Scientific Name: Strix varia Barton, 1799
English Name: Barred Owl
 
Classification / Taxonomy
Scientific Name - Concept Reference: American Ornithological Society (AOS). Chesser, R. T., S. M. Billerman, K. J. Burns, C. Cicero, J. L. Dunn, B. E. Hernández-Baños, A. W. Kratter, I. J. Lovette, N. A. Mason, P. C. Rasmussen, J. V. Remsen, Jr., D. F. Stotz, and K. Winker. 2021. Sixty-second Supplement to the American Ornithological Society?s Check-list of North American Birds. Ornithology 138:1-18.
Classification Level: Species
Species Group: Vertebrate Animal
Species Code: B-BDOW
Kingdom Phylum Class Order Family
Animalia Craniata Aves Strigiformes Strigidae
   
Conservation Status / Legal Designation
Global Status: G5 (Apr 2016)
Provincial Status: S5 (Mar 2015)
BC List: Yellow
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status:
SARA Schedule:
General Status Canada: 4 - Secure (2005)
Migratory Bird Convention Act:
   
Ecology & Life History
General Description:
Global Reproduction Comments: Egg dates: late March-May in southern New England, late February-April in New Jersey, Illinois, and Iowa, January-March in Florida. Nesting peaks from early March to early May in Maryland (see Bushman and Therres 1988). Clutch size usually is 2-3. Incubation lasts 28-33 days. Young may leave nest at 4-5 weeks, fly at 6 weeks, may still receive some food from parents at 4 months.
Global Ecology Comments: Home range usually is less than 400 ha (but up to 760 ha) over 2-7 months in Minnesota, average 273 hectares; usually no overlap except in mated pair; boundaries generally are constant from year to year (Nicholls and Warner 1972). Annual home range averaged 282 hectares in Michigan (Elody and Sloan 1985) and 971 hectares in Saskatchewan (Mazur et al. 1998). Reported density: 0.03-1.0 pairs/sq km.

Expanding populations in Pacific Northwest could threaten spotted owl through competiton and/or hybridization (see Hamer et al. 1994).
Migration Characteristics:
(Global / Provincial)
 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant:
Y /
Y /
N /
na /
Global Migration Comments: Northernmost populations partially migratory. None of 158 band recoveries in North America occurred more than 10 km from banding location (Johnson 1987).
Habitats:
(Type / Subtype / Dependence)
Agriculture / Cultivated Field / Unknown
Agriculture / Hedgerow / Unknown
Agriculture / Pasture/Old Field / Unknown
Alpine/Tundra / Krummholtz / Unknown
Anthropogenic / Urban/Suburban / Unknown
Forest / Conifer Forest - Dry / Unknown
Forest / Conifer Forest - Mesic (average) / Unknown
Forest / Conifer Forest - Moist/wet / Unknown
Riparian / Riparian Forest / Unknown
Wetland / Bog / Unknown
Wetland / Fen / Unknown
Wetland / Marsh / Unknown
Wetland / Swamp / Unknown
Global Habitat Comments: Dense woodland and forest (coniferous or hardwood), swamps, wooded river valleys, cabbage palm-live oak hammocks; often in areas bordering streams, marshes, and meadows (AOU 1983), but also commonly in upland areas; habitat use reflects vegetation characteristics rather than proximity of water per se. Generally in expansive forested area with large mature and decadent trees that provide cavities suitable for security and nesting (Allen 1987). Appears to prefer older stands but uses earlier stages of forest succession if enough large trees or snags (or nest boxes) are present (Allen 1987). Often in forests with relatively open understory. Prefers canopy closure of 60% or greater. Often replaced by the great horned owl in fragmented open forests.

Nests in tree cavity, in abandoned nest of squirrel, crow, or hawk, or in top of hollow tree stub, usually at least 7-8 m above ground. Uses both living and dead trees. Trees with cavity suitable for nesting generally at least 51 cm DBH; habitat suitability index model assumes that a density of at least 2 stems of this diameter per 0.4 ha represents high quality habitat for reproduction; high quality reproductive habitat also indicated by canopy cover of overstory trees of 60% or more (Allen 1987). Nest sites typically used in successive years.
Food Habits: Carnivore: Adult, Immature
Invertivore: Adult, Immature
Global Food Habits Comments: Eats mostly mice but also wide variety of other mammals, birds, reptiles, amphibians, and invertebrates (Terres 1980). Small mammals such as MICROTUS, PEROMYSCUS, and BLARINA often comprise bulk of diet. In Mississippi, invertebrates (especially crayfishes) may be more important than small mammals (see Allen 1987). Little used habitats such as marshes and old fields may nevertheless be important as sources of prey organisms that immigrate into cover types favored by the owls (Allen 1987).
Global Phenology: Crepuscular: Adult, Immature
Nocturnal: Adult, Immature
Global Phenology Comments: Birds feeding young may also forage diurnally. Opportunistic foraging may occur at any time.
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: N
Length(cm)/width(cm)/Weight(g): 53/ / 801
Elevation (m) (min / max): Global: 
Provincial: 
   
 
Distribution
Endemic: N
Global Range Comment: RESIDENT from southeastern Alaska (possibly), British Columbia (Dunbar et al. 1991), western Washington, eastern Oregon (probably), and northeastern California east through northern Idaho, northwestern Montana, central Alberta, and central Saskatchewan, and from southern Manitoba east to southern Quebec and Nova Scotia, and south to southern Texas, Gulf Coast and southern Florida, west to eastern Great Plains woodlands. Map in Allen (1987) shows range extending north to extreme southeastern Yukon and extreme southwestern Northwest Territories, and does not include southeastern Alaska. Range has expanded into Pacific Northwest in last few decades (e.g., see Sharp 1989); now common in forested areas in southwestern British Columbia and northern Washington and rapidly increasing in Oregon and northern California (see Hamer et al. 1994). Range expansion apparently associated with conversion of pure coniferous forest to mixed deciduous-coniferous forest as a result of lumbering (see Allen 1987).
 
Authors / Contributors
Global Information Author: HAMMERSON, G., MINOR REVISIONS BY S. CANNINGS
Last Updated: Mar 08, 1995
Provincial Information Author:
Last Updated:
   
References and Related Literature
Allen, A. W. 1987. Habitat suitability index models: barred owl. U.S. Fish Wildl. Serv. Biol. Rep. 82(10.143). 17 pp.
American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.
Bell, R. E. 1964. A sound triangulation method for counting barred owls. Wilson Bull. 76:292-294.
Bent, A. C. 1938. Life histories of North American birds of prey. Part 2. U.S. Nat. Mus. Bull. 170. 482 pp., 92 pls.
Bosakowski, T. 1987. Census of barred owls and spotted owls. Pages 307-308 in Nero, R. W., et al., eds. Biology and conservation of northern forest owls. USDA For. Serv., Gen. Tech. Rep. RM-142.
Bosakowski, T., et al. 1987. Distribution, density, and habitat relationships of the barred owl.... Pp. 135-143 in Nero, R. W., et al., eds. Biology and conserv. of northern forest owls. USDA For. Serv., Gen. Tech Rep. RM-142.
Bushman, E. S., and G. D. Therres. 1988. Habitat management guidelines for forest interior breeding birds of coastal Maryland. Maryland Dept. Natural Resources, Wildlife Tech. Publ. 88-1. 50 pp.
Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, J.M. Cooper, G.W. Kaiser, and M.C.E. McNall. 1990b. The Birds of British Columbia Vol. 2: Nonpasserines: Diurnal Birds of Prey through Woodpeckers. Royal British Columbia Museum, Victoria, BC.
Clark, R. J., D. G. Smith, and L. H. Kelso. 1978. Working bibliography of owls of the world. National Wildlife Federation, Sci. & Tech. Ser. No. 1. 336 pp.
Demarchi, M.W. and M.D. Bently. 2005. Best Management Practices for Raptor Conservation during Urban and Rural Land Development in British Columbia. B.C. Minist. of Environ., Victoria, B.C. MoE BMP Series.
Dunbar, D. L., et al. 1991. Status of the spotted owl, STRIX OCCIDENTALIS, and barred owl, STRIX VARIA, in southwestern British Columbia. Canadian Field-Naturalist 106:464-468.
Eckert, Allan W. 1978. The Owls of North America. Weather-vane Books, New York. 278 pp.
Elody, B. I., and N. F. Sloan. 1985. Movements and habitat use of Barred Owls in the Huron Mountains of Marquette County, Michigan, as determined by radiotelemetry. Jack Pine Warbler 63:3-8.
Fisher, A.K. 1893. The hawks and owls of the United States in their relation to agriculture. Washington U.S. Dept. of Agriculture Bull. no. 6. 210 pp.
Fuller, M. R., and J. A. Mosher. 1987. Raptor survey techniques. Pages 37-65 in B. A. Giron Pendleton, et al., eds. Raptor management techniques manual. National Wildlife Federation, Washington, D.C.
Hamer, T. E., et al. 1994. Hybridization between barred and spotted owls. Auk 111:487-492.
Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.
Harrison, H. H. 1979. A field guide to western birds' nests. Houghton Mifflin Company, Boston. 279 pp.
Johnsgard, P. 1988. North American owls: biology and natural history. Smithsonian Inst. Press. 336 pp.
Johnson, D. H. 1987. Barred owls and nest boxes--results of a five-year study in Minnesota. Pages 129-134 in Nero, R. W., et al., eds. Biology and conservation of northern forest owls. USDA For. Serv., Gen. Tech. Rep. RM-142.
Mazur, K. M., S. D. Frith, and P. C. James. 1998. Barred Owl home range and habitat selection in the boreal forest of central Saskatchewan. Auk 115:746-754.
McGarigal, K., and J. D. Fraser. 1985. Barred owl responses to recorded vocalizations. Condor 87:552-553.
Nicholls, T. H. and D. W. Warner. 1972. Barred owl habitat use as determined by radiotelemetry. J. Wildl. Manage. 36: 213-224.
Nicholls, T. H., and M. R. Fuller. 1987. Owl telemetry techniques. Pages 294-301 IN R.W. Nero, R.J. Clark, R.J. Knapton, and R.H. Hamre, editors. Biology and conservation of northern forest owls. USDA Forest Service, Gen. Tech. Rep. RM-142.
Pendleton, B. A. G., B. A. Millsap, K. W. Cline, and D. M. Bird. 1987. Raptor management techniques manual. National Wildlife Federation, Sci. and Tech. Ser. No. 10. 420 pp.
Sharp, D. U. 1989. Range extension of the barred owl in western Washington and first breeding record on the Olympic Peninsula. J. Raptor Res. 23:179-180.
Sibley, C.G., and B.L. Monroe, Jr. 1990. Distribution and Taxonomy of Birds of the World. Yale University Press, New Haven, CT. xxiv + 1111 pp.
Smith, D.G. 1987b. Owl census techniques. Pages 304-307 in R.W. Nero, R.J. Clark, R.J. Knapton, and R.H. Hamre, editors. Biology and conservation of northern forest owls. USDA Forest Service, Gen. Tech. Rep. RM-142.
Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.
Voous, K. H., and A. Cameron. 1989. Owls of the Northern Hemisphere. MIT Press, Cambridge, Massachusetts. 320 pp.
Walker, L.W. 1974. The book of owls. Alfred A. Knopf, Inc. New York. 255 pp.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 1995. Species Summary: Strix varia. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Aug 11, 2022).