Great Grey Owl

Strix nebulosa

General Status Rank: 
Secure
ELCODE: 
ABNSB12040
Common Name: 
Great Grey Owl
Scientific Name: 
Strix nebulosa
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Taxonomy
Group: 
Bird
Kingdom: 
Animalia
Phylum: 
Chordata
Class: 
Aves
Order: 
Strigiformes
Family: 
Strigidae
References: 
B004
General Biology

Female Age at Maturity

Rarely breeds at 1 yr, occasionally at 2 yr, more commonly at 3 yr (ELB, JRD).
References: 
B140

Longevity

9-13 yr
References: 
B140
Habitat
extensive boreal forest interspersed with Sphagnum bogs, muskegs, and other open spaces (B004); natural openings in dense northern forest, such as bogs or montane meadows, where it preys on small mammals (W027)
References: 
B004
H126
R061
W027
Distribution

Ecozones

Taiga Cordillera, Taiga Plains, Taiga Shield, Boreal Cordillera, Boreal Plains
References: 
B004

Distribution

0.597; Uncommon permanent resident in forests below the treeline on the mainland, northwards up the Mackenzie Valley to Colville Lake and Fort Good Hope. Rarely further north as far as Reindeer Station. Some birds likely move south out of the Territory during winter.(NWT Bird checklist project)
Score: 
G
References: 
B004
Winter Distribution Description: 
in breeding range and southward

Number of Occurrences

Prob. More than 100 in NWt; widespread
Score: 
D
References: 
H126

Area of Occupancy

dispersion to southern parts during vole crashes; overall dist. Prob. Stable
Score: 
-
References: 
H126
LWR01
R061
W027
Population

Population Size

10,000 - 25,000 breeding pairs (in Canada); based on distribution about 1/6 in NWT = 3000 to 8000, More than 1000, may be less than 10 000
Score: 
DE
References: 
H126
R061

Density

from 4.2 pairs per square kilometer in high vole years to 0 in crash years (R061); 1.88 pairs/km2 in Manitoba (B140)
Trends

Trends

small term fluctuations coinciding with vole/mice populations; trend unknown in NWT but assumed stable; National trend 3 (stable)
References: 
H126
LWR01
R061
W027
Threats

Threats

unknown - prob. Limited
Score: 
C
References: 
H126
R061
B140

Intrinsic Vulnerability

forestry - creation of homogenous stands; threats limited in NWt
Score: 
-
References: 
H126
R061
B140
General Status Rank
Rank: 
Secure
Status Rank Description: 
threats appear limited in NWT
S Rank: 
S4
Decision Process Description: 
Drafted by Suzanne Carriere based on printed references. Reviewed in 2005, no change in status; Reviewed in 2010;no change; Reviewed in 2015, no change; Reviewed in 2020, no change
Last Updated: 
June 30, 2020
Status Designations

Canada – Assessment by Committee on the Status of Endangered Wildlife in Canada

COSEWIC Status: 
Not At Risk
References: 
R061

References

Age Of Maturity

  • Bull, E. L. and J. R. Duncan. (1993) Great Gray Owl (Strix nebulosa).. Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists’ Union. In The Birds of North America, No. 41 (A. Poole and F. Gill, Eds.). - B140 Return

Area of Occupancy

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Downes, C.M., E.H. Dunn and C.M Francis (2000) Canadian Landbird Monitoring Strategy: monitoring needs and priorities into the new millenium.. Partners in Flight - Canada A 9-15 EC-CWS, Yellowknife (L. Wakelyn) - or communicate with Erica H. Dunn, CWS in Hull, QC, at erica.dunn@ec,gc,ca - LWR01 Return
  • Kirk DA, and Duncan JR (1996) Updated status report on the great grey owl Strix Nebulosa in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R061 Return
  • Dunn, E.H (2005) National action needs for Canadian Landbird Conservation,. Canadian Wildlife Service Landbird Committee, Version 1. [http://www.cws-scf.ec.gc.ca/birds/action/index_e.cfm]. - W027 Return
COSEWIC Status
  • Kirk DA, and Duncan JR (1996) Updated status report on the great grey owl Strix Nebulosa in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R061 Return

Ecozones

  • Godfrey WE (1986) The Birds of Canada. National Museums of Canada Revised Edition RWED Library Call #QL685.G6 - B004 Return

Habitat

  • Godfrey WE (1986) The Birds of Canada. National Museums of Canada Revised Edition RWED Library Call #QL685.G6 - B004 Return
  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Kirk DA, and Duncan JR (1996) Updated status report on the great grey owl Strix Nebulosa in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R061 Return
  • Dunn, E.H (2005) National action needs for Canadian Landbird Conservation,. Canadian Wildlife Service Landbird Committee, Version 1. [http://www.cws-scf.ec.gc.ca/birds/action/index_e.cfm]. - W027 Return

Intrinsic Vulnerability

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Kirk DA, and Duncan JR (1996) Updated status report on the great grey owl Strix Nebulosa in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R061 Return
  • Bull, E. L. and J. R. Duncan. (1993) Great Gray Owl (Strix nebulosa).. Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists’ Union. In The Birds of North America, No. 41 (A. Poole and F. Gill, Eds.). - B140 Return

Longevity

  • Bull, E. L. and J. R. Duncan. (1993) Great Gray Owl (Strix nebulosa).. Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists’ Union. In The Birds of North America, No. 41 (A. Poole and F. Gill, Eds.). - B140 Return

NWT Known Subspecies

Godfrey WE (1986) The Birds of Canada. National Museums of Canada Revised Edition RWED Library Call #QL685.G6 - B004 Return

Number of Occurrences

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return

Population Size

Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
,
Kirk DA, and Duncan JR (1996) Updated status report on the great grey owl Strix Nebulosa in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R061 Return

Range Extent

  • Godfrey WE (1986) The Birds of Canada. National Museums of Canada Revised Edition RWED Library Call #QL685.G6 - B004 Return

Short Term Trends

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Downes, C.M., E.H. Dunn and C.M Francis (2000) Canadian Landbird Monitoring Strategy: monitoring needs and priorities into the new millenium.. Partners in Flight - Canada A 9-15 EC-CWS, Yellowknife (L. Wakelyn) - or communicate with Erica H. Dunn, CWS in Hull, QC, at erica.dunn@ec,gc,ca - LWR01 Return
  • Kirk DA, and Duncan JR (1996) Updated status report on the great grey owl Strix Nebulosa in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R061 Return
  • Dunn, E.H (2005) National action needs for Canadian Landbird Conservation,. Canadian Wildlife Service Landbird Committee, Version 1. [http://www.cws-scf.ec.gc.ca/birds/action/index_e.cfm]. - W027 Return

Taxonomy

  • Godfrey WE (1986) The Birds of Canada. National Museums of Canada Revised Edition RWED Library Call #QL685.G6 - B004 Return

Threats

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Kirk DA, and Duncan JR (1996) Updated status report on the great grey owl Strix Nebulosa in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R061 Return
  • Bull, E. L. and J. R. Duncan. (1993) Great Gray Owl (Strix nebulosa).. Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists’ Union. In The Birds of North America, No. 41 (A. Poole and F. Gill, Eds.). - B140 Return