Roadless Areas
Home/Species/ Great Gray Owl

Strix nebulosa

Forster, 1772

Great Gray Owl

G5Secure Found in 91 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
Identity
Unique IDELEMENT_GLOBAL.2.100756
Element CodeABNSB12040
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
CITESAppendix II
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassAves
OrderStrigiformes
FamilyStrigidae
GenusStrix
Other Common Names
Chouette lapone (FR) Great Grey Owl (EN)
Concept Reference
American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Conservation Status
Rank MethodExpertise without calculation
Review Date2016-04-10
Change Date1996-11-27
Rank Reasons
Large circumboreal range; no decline is evident in the vast majority of the range, but few data are available for most areas.
Range Extent Comments
BREEDS: central Alaska to northern Ontario, south locally in mountains to California (vicinity of Yosemite), Idaho, Montana, Wyoming, central Saskatchewan, northern Minnesota, and south-central Ontario. WINTERS: generally throughout breeding range, wandering south irregularly to northern U.S. Also in Old World. Usually uncommon, but sometimes may be locally abundant.
Threat Impact Comments
In California, habitat loss through logging of mature forest and overgrazing of meadows has been the primary cause for decline (California Department of Fish and Game 1990).
Ecology & Habitat

Habitat

Dense coniferous and hardwood forest, especially pine, spruce, paper birch, poplar; also second growth, especially near water, foraging in wet meadows; boreal forest and spruce-tamarack bogs in far north, coniferous forest and meadows in mountains.

Nests in top of large broken-off tree trunks (especially in south), in old nests of other large birds (e.g., hawk nest) (especially in north), or in debris platforms from dwarf mistletoe; frequently near bogs or clearings. Nests frequently reused (Franklin 1988). Same pair often nests in same area in successive years.

Ecology

Some may remain on breeding territory all year; others may move irregularly in search of favorable foraging conditions. In Oregon, radio-tagged juveniles moved 9-31 km from nest over period of 1 year, adults moved 3-43 km during same period (see Johnsgard 1988). Predation by great horned owl was greatest known mortality factor in northern Minnesota and southeastern Manitoba (Duncan 1987).

Reproduction

Egg dates: late March-May in Alberta, late April-early June in Ontario, peak mid-April to late May in California, mean date of first egg 5 May in southern Idaho and northwestern Wyoming; eggs laying may be delayed in years with deep snow (Franklin 1988). Clutch size is 2-5 (usually 2-3 or 3-4). Incubation lasts 28-29 days, by female (male brings food). Young begin to leave nest at 3-4 weeks (4 weeks in Idaho/Wyoming), fly well at 5-6 weeks (6 weeks in Idaho/Wyoming), independent at about 4-5 months (Idaho/Wyoming: Franklin 1988). Usually first breeds at 3-4 years. Pair bond is not maintained outside breeding season, but bond may reform if both birds return to the same breeding territory. Some pairs may not breed in years of low prey abundance.
Terrestrial Habitats
Forest - HardwoodForest - ConiferForest - MixedWoodland - HardwoodWoodland - ConiferWoodland - MixedGrassland/herbaceous
Palustrine Habitats
Bog/fenRiparian
Other Nations (2)
United StatesN4
ProvinceRankNative
MichiganSNRNYes
MinnesotaSNRYes
IdahoS3Yes
WashingtonS2BYes
New YorkSNRNYes
WyomingS2Yes
MontanaS3Yes
CaliforniaS1Yes
OregonS3Yes
AlaskaS4Yes
MaineS1NYes
UtahS1NYes
CanadaN5
ProvinceRankNative
AlbertaS5Yes
QuebecS4Yes
SaskatchewanS3Yes
Northwest TerritoriesS4Yes
ManitobaS3Yes
British ColumbiaS4Yes
OntarioS4Yes
Yukon TerritoryS3Yes
Roadless Areas (91)
California (7)
AreaForestAcres
AgnewSequoia National Forest9,561
Devil GulchSierra National Forest30,490
Ferguson RidgeSierra National Forest6,104
Kings RiverSierra National Forest52,999
MosesSequoia National Forest22,077
North MountainStanislaus National Forest7,856
San JoaquinSierra National Forest22,474
Idaho (7)
AreaForestAcres
HoodooNez Perce-Clearwater National Forest153,868
Italian PeakCaribou-Targhee National Forest141,158
Lemhi RangeSalmon-Challis National Forest308,533
NeedlesPayette National Forest131,279
PalisadesCaribou-Targhee National Forest122,002
SeceshPayette National Forest248,088
West Meadow CreekNez Perce-Clearwater National Forest115,949
Michigan (1)
AreaForestAcres
DeliriumHiawatha National Forest190
Minnesota (3)
AreaForestAcres
Cabin CreekSuperior National Forest6,071
Phantom LakeSuperior National Forest6,521
Wood LakeSuperior National Forest596
Montana (33)
AreaForestAcres
Allan Mountain (01946)Bitterroot National Forest104,184
Anderson MountainBeaverhead-Deerlodge National Forest31,501
Bear - Marshall - Scapegoat - SwanHelena National Forest51,360
Bear - Marshall - Scapegoat - SwanLolo National Forest118,485
Bear - Marshall - Scapegoat - SwanLewis and Clark National Forest344,022
Beaver LakeBeaverhead-Deerlodge National Forest11,863
Big BaldyLewis and Clark National Forest43,135
Big Horn MountainBeaverhead-Deerlodge National Forest50,846
BridgerGallatin National Forest45,059
Continental Divide National Scenic TrailBitterroot National Forest312
Crazy MountainGallatin National Forest82,093
Deadhorse Ridge Ra 1128Flathead National Forest23,648
East PioneerBeaverhead-Deerlodge National Forest145,082
FleecerBeaverhead-Deerlodge National Forest31,585
Gallatin FringeGallatin National Forest51,571
Garfield MountainBeaverhead-Deerlodge National Forest41,891
Goat MountainBeaverhead-Deerlodge National Forest9,348
Hyalite - Porcupine - Buffalo Horn Wilderness Study AreaGallatin National Forest143,991
Italian PeakBeaverhead-Deerlodge National Forest90,401
LionheadGallatin National Forest33,549
MadisonGallatin National Forest127,859
Marston Face # 172Kootenai National Forest9,098
Mt. JeffersonBeaverhead-Deerlodge National Forest4,482
North AbsarokaGallatin National Forest159,075
North AbsarokaCuster National Forest21,063
North Big HoleBeaverhead-Deerlodge National Forest52,227
North Big HoleBitterroot National Forest3,483
Silver KingBeaverhead-Deerlodge National Forest64,289
Silver King - Falls CreekHelena National Forest6,811
Upper East ForkBeaverhead-Deerlodge National Forest8,905
VigilanteBeaverhead-Deerlodge National Forest15,893
West Big HoleBeaverhead-Deerlodge National Forest133,563
West PioneerBeaverhead-Deerlodge National Forest248,631
Oregon (20)
AreaForestAcres
AntlerFremont National Forest5,498
Bend WatershedDeschutes National Forest14,829
Brown Mt.Winema National Forest3,117
Buck CreekFremont National Forest9,887
BuckhornWallowa-Whitman National Forest17,180
Crane MountainFremont National Forest23,096
French Pete (a)Willamette National Forest1,668
Gold CreekWillamette National Forest1,364
Greenhorn MountainMalheur National Forest15,936
Greenhorn Mtn.Umatilla National Forest11,191
HellholeUmatilla National Forest65,679
Hurricane CreekWallowa-Whitman National Forest1,606
Lookout MountainOchoco National Forest14,115
Mclennon MountainWillamette National Forest8,085
Mill Creek Watershed (OR)Umatilla National Forest7,820
Mt. JeffersonDeschutes National Forest2,282
Sky Lakes AWinema National Forest3,940
Snake RiverWallowa-Whitman National Forest31,229
Tope CreekWallowa-Whitman National Forest9,237
W. BoundaryWinema National Forest2,345
Utah (1)
AreaForestAcres
Stump CreekCaribou National Forest355
Washington (4)
AreaForestAcres
Mill Creek Watershed (WA)Umatilla National Forest16,747
Mt. Baker MaMt Baker-Snoqualmie National Forest24,847
ProfanityColville National Forest28,944
SpanglerUmatilla National Forest5,936
Wyoming (15)
AreaForestAcres
Dunoir Special Management UnitShoshone National Forest29,719
Grayback RidgeBridger-Teton National Forest295,113
Gros Ventre MountainsBridger-Teton National Forest106,418
Lake Alice - Commissary RidgeBridger-Teton National Forest166,707
Middle ForkShoshone National Forest51,772
Pacific Creek - Blackrock CreekBridger-Teton National Forest24,658
PalisadesTarghee National Forest1,121
Phillips RidgeBridger-Teton National Forest10,108
Salt River RangeBridger-Teton National Forest235,661
Sheridan PassShoshone National Forest8,394
Spread Creek - Gros Ventre RiverBridger-Teton National Forest166,097
Teton Corridor TrailheadsBridger-Teton National Forest286
West Slope TetonsTarghee National Forest47,448
West Slope WindsBridger-Teton National Forest143,252
Wilderness Study AreaTarghee National Forest51,961
References (41)
  1. American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.
  2. American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in <i>The Auk</i>]. Also available online: http://www.aou.org/.
  3. Baekken, B. T., J. O. Nybo, and G. A. Sonerud. 1987. Home range size of Hawk Owls: dependence on calculation method, number of tracking days, and number of plotted perches. Pp. 145-148 IN Nero, R.W., R. J. Clark, R. J. Knapton, and H. Hamre, eds. Biology and conservation of northern forest owls. USDA For. Serv. Gen. Tech. Rep. RM-142, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO.
  4. Bent, A. C. 1938. Life histories of North American birds of prey. Part 2. U.S. Nat. Mus. Bull. 170. 482 pp., 92 pls.
  5. Bull, E.L. 1987. Capture techniques for owls. Pages 291-293 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.
  6. Bull, E. L., et al. 1987. Nest platforms for great gray owls. Pp. 87-90 in Nero, R. W., et al., eds. Biology and conservation of northern forest owls. USDA Forest Service, Gen.Tech. Rep. RM-142.
  7. Byrd, C. L. 1982. Home range, habitat and prey utilization of the barn owl in south Texas. Texas A and I University, Kingsville, Texas. M.S. thesis. 64 pp.
  8. Byrd, M. A., and D. W. Johnston. 1991. Birds. Pages 477-537 in K. Terwilliger, coordinator. Virginia's endangered species: proceedings of a symposium. McDonald and Woodward Publ. Co., Blacksburg, Virginia.
  9. California Department of Fish and Game (CDF&G). 1990. 1989 annual report on the status of California's state listed threatened and endangered plants and animals. 188 pp.
  10. 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.
  11. Colvin, B. A. 1984. Barn owl foraging behavior and secondary poisoning hazard from rodenticide use on farms. Bowling Green State University, Bowling Green, Ohio. 326 pp. Ph.D. dissertation.
  12. Craighead, J. J., and F. C. Craighead, Jr. 1956. Hawks, Owls and Wildlife. The Stackpole Company, Harrisburg, Pennsylvania, and the Wildlife Management Institute, Washington, D.C.
  13. Duncan, J., and P. Duncan. 1994/95. Nocturnal owl surveys. Bird Trends (Canadian Wildlife Service) (4):24-25.
  14. Duncan, J. R. 1987. Movement strategies, mortality, and behavior of radio-marked great gray owls. Pp. 101-107 IN Nero, R.W., R. J. Clark, R. J. Knapton, and H. Hamre, eds. Biology and conservation of northern forest owls. USDA For. Serv. Gen. Tech. Rep. RM-142, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO.
  15. Eckert, Allan W. 1978. The Owls of North America. Weather-vane Books, New York. 278 pp.
  16. 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.
  17. 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.
  18. Franklin, A. B. 1988. Breeding biology of the great gray owl in southeastern Idaho and northwestern Wyoming. Condor 90:689-696.
  19. Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.
  20. Hayward, G. D., and J. Verner, editors. 1994. Flammulated, boreal, and great gray owls in the United States: a technical conservation assessment. USDA Forest Service, General Technical Report RM-253. Fort Collins, Colorado.
  21. Hegdal, P. L., and R. W. Blaskiewicz. 1984. Evaluation of the potential hazard to barn owl of Talon (<i>Brodifacoum</i> bait) used to control rats and house mice. Environmental Toxicology and Chemistry 3:167-79.
  22. Johnsgard, P. 1988. North American owls: biology and natural history. Smithsonian Inst. Press. 336 pp.
  23. Kirk, D. A., D. Hussell, and E. Dunn. 1995. Raptor population status and trends in Canada. Bird Trends (Canadian Wildlife Service) 4:2-9.
  24. 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.
  25. National Geographic Society (NGS). 1983. Field guide to the birds of North America. National Geographic Society, Washington, DC.
  26. Nero, R. W. 1980. The great gray owl: phantom of the northern forest. Smithsonian Institution Press, Blue Ridge Summit, PA. 168 pp.
  27. 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.
  28. 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.
  29. Quinton, M. S. 1988. Ghost of the forest: the great gray owl. Northland. 99 pp.
  30. Rohner, C. 1997. Non-territorial 'floaters' in Great Horned Owls: space use during a cyclic peak of snowshoe hares. Animal Behaviour 53:901-912.
  31. Rosenburg, C. P. 1986. Barn owl habitat and prey use in agricultural eastern Virginia. College of William and Mary, Williamsburg, Virginia. M.S. thesis. 114 pp.
  32. Servos, M. C. 1987. Summer habitat use by great gray owls in southeastern Manitoba. Pp. 108-114 in Nero, R. W., et al., eds. Biology and conservation of northern forest owls. USDA For. Serv., Gen. Tech. Rep. RM-142.
  33. Smith, D. G. 1969. Nesting ecology of the Great Horned Owl, <i>Bubo virginianus</i>. Brigham Young University Science Bulletin Biol. Series 10(4):16-25.
  34. 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.
  35. Spahr, R., L. Armstrong, D. Atwood, and M. Rath. 1991. Threatened, endangered, and sensitive species of the Intermountain Region. U.S. Forest Service, Ogden, Utah.
  36. Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.
  37. Thomas, J. W., Ward, J., Raphael, M.G., Anthony, R.G., Forsman, E.D., Gunderson, A.G., Holthausen, R.S., Marcot, B.G., Reeves, G.H., Sedell, J.R. and Solis, D.M. 1993. Viability assessments and management considerations for species associated with late-successional and old-growth forests of the Pacific Northwest. The report of the Scientific Analysis Team. USDA Forest Service, Spotted Owl EIS Team, Portland Oregon. 530 pp.
  38. U.S. Forest Service (USFS), et al. 1993. Draft supplemental environmental impact statement on management of habitat for late-successional and old-growth forest related species within the range of the northern spotted owl. Published separately is Appendix A: Forest Ecosystem Management Assessment Team. 1993. Forest ecosystem management: an ecological, economic, and social assessment (FEMAT Report).
  39. Voous, K. H., and A. Cameron. 1989. Owls of the Northern Hemisphere. MIT Press, Cambridge, Massachusetts. 320 pp.
  40. Walker, L.W. 1974. The book of owls. Alfred A. Knopf, Inc. New York. 255 pp.
  41. Winter, J. 1982. Further investigations on the ecology of the great gray owl in the central Sierra Nevada. U.S. Department of Agriculture, Forest Service, Stanislaus National Forest, Sonora, CA. Final Report. Contract No. 43-2348. 35pp.