Map_thumbnail_large_font

Strix nebulosa 

Scope: Global
Language: English
Status_ne_offStatus_dd_offStatus_lc_onStatus_nt_offStatus_vu_offStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

Translate page into:

Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Strigiformes Strigidae

Scientific Name: Strix nebulosa Forster, 1772
Regional Assessments:
Common Name(s):
English Great Grey Owl, Great Gray Owl
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Butchart, S., Ekstrom, J. & Ashpole, J
Justification:
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be fluctuating, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Previously published Red List assessments:

Geographic Range [top]

Countries occurrence:
Native:
Belarus; Canada; China; Finland; Kazakhstan; Lithuania; Mongolia; Norway; Russian Federation (Central Asian Russia, Eastern Asian Russia, European Russia); Sweden; Ukraine; United States
Regionally extinct:
Latvia
Vagrant:
Germany; Poland
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:44700000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):3200
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The global population is estimated to number approximately 190,000 individuals which equates to 127,000 mature individuals (Partners in Flight Science Committee 2013). The North American population is estimated at 90,000 individuals or 60,000 mature individuals (Partners in Flight Science Committee 2013). The European population is estimated at 1,900-7,500 pairs, which equates to 3,900-15,000 mature individuals (BirdLife International 2015). Europe forms approximately 13% of the global range, so a very preliminary estimate of the global population size is 30,000-115,000 mature individuals, although further validation of this estimate is needed. The population is precautionarily placed in the band 50,000-99,999 mature individuals but the actual population could be considerably larger.

Trend Justification:  The overall trend is likely to be increasing. This species has undergone a large and statistically significant increase over the last 40 years in North America (4900% increase over 40 years, equating to a 166% increase per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). Note, however, that these surveys cover less than 50% of the species's range in North America. In Europe the population size is also estimated to be increasing (BirdLife International 2015).
Current Population Trend:Increasing
Additional data:
Number of mature individuals:50000-99999Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Threats [top]

Major Threat(s): The species is affected by global warming, which if it persists will continue to move the species’s range northwards (Hagemeijer and Blair 1997). Populations fluctuate in line with vole numbers (Cornulier et al. 2013). Locally, hunting may still be a threat (König 2008). It is also vulnerable to road traffic collisions and loss of habitat from forestry (Holt et al. 1999). Collisions with power lines and cables are also a threat. In North America timber harvesting, collisions with vehicles, strychnine poisoning of pocket gophers, disturbance at foraging habitats due to development of campsites, grazing, peat extraction and agriculture have all been identified as potential threats (Holt et al. 1999). The species is known to be vulnerable to West Nile Virus (Lopes et al. 2007).

Classifications [top]

1. Forest -> 1.1. Forest - Boreal
suitability:Suitable season:resident major importance:Yes
3. Shrubland -> 3.3. Shrubland - Boreal
suitability:Suitable season:resident major importance:No
4. Grassland -> 4.2. Grassland - Subarctic
suitability:Suitable season:resident major importance:No
5. Wetlands (inland) -> 5.4. Wetlands (inland) - Bogs, Marshes, Swamps, Fens, Peatlands
suitability:Suitable season:resident major importance:No
14. Artificial/Terrestrial -> 14.2. Artificial/Terrestrial - Pastureland
suitability:Marginal season:non-breeding 

In-Place Research, Monitoring and Planning
  Action Recovery plan:No
  Systematic monitoring scheme:No
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over entire range
  Occur in at least one PA:Yes
  Invasive species control or prevention:No
In-Place Species Management
  Successfully reintroduced or introduced beningly:No
  Subject to ex-situ conservation:No
In-Place Education
  Subject to recent education and awareness programmes:No
  Included in international legislation:Yes
  Subject to any international management/trade controls:Yes
1. Residential & commercial development -> 1.3. Tourism & recreation areas
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Low Impact: 5 
→ Stresses
  • 2. Species Stresses -> 2.2. Species disturbance

11. Climate change & severe weather -> 11.1. Habitat shifting & alteration
♦ timing:Ongoing ♦ scope:Whole (>90%) ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation
  • 1. Ecosystem stresses -> 1.3. Indirect ecosystem effects

2. Agriculture & aquaculture -> 2.2. Wood & pulp plantations -> 2.2.2. Agro-industry plantations
♦ timing:Ongoing ♦ scope:Majority (50-90%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Medium Impact: 6 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

2. Agriculture & aquaculture -> 2.3. Livestock farming & ranching -> 2.3.4. Scale Unknown/Unrecorded
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Low Impact: 5 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation
  • 2. Species Stresses -> 2.2. Species disturbance

4. Transportation & service corridors -> 4.1. Roads & railroads
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Negligible declines ⇒ Impact score:Low Impact: 4 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

4. Transportation & service corridors -> 4.2. Utility & service lines
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Negligible declines ⇒ Impact score:Low Impact: 4 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.1. Hunting & trapping terrestrial animals -> 5.1.1. Intentional use (species is the target)
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Negligible declines ⇒ Impact score:Low Impact: 4 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.2. Gathering terrestrial plants -> 5.2.2. Unintentional effects (species is not the target)
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Low Impact: 5 
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

8. Invasive and other problematic species, genes & diseases -> 8.5. Viral/prion-induced diseases -> 8.5.2. Named species
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Low Impact: 5 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

9. Pollution -> 9.3. Agricultural & forestry effluents -> 9.3.3. Herbicides and pesticides
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Negligible declines ⇒ Impact score:Low Impact: 4 
→ Stresses
  • 1. Ecosystem stresses -> 1.3. Indirect ecosystem effects

Bibliography [top]

BirdLife International. 2015. European Red List of Birds. Office for Official Publications of the European Communities, Luxembourg.

Cornulier, T., Yoccoz, N.G., Bretagnolle, V., Brommer, J.E., Butet, A., Ecke, F., Elston, D.A., Framstad, E., Henttonen, H., Hörnfeldt, B., Huitu, O., Imholt, C., Ims, R.A., Jacob, J., Jędrzejewska, B., Millon, A., Petty, S.J., Pietiäinen, H., Tkaadlec, E., Zub, K. and Lambin, X. 2013. Europe-wide dampening of population cycles in keystone herbivores. Science 340(6128): 63-66.

Hagemeijer, E.J.M. and Blair, M.J. 1997. The EBCC atlas of European breeding birds: their distribution and abundance. T. and A. D. Poyser, London.

Holt, D.W., Berkley, R., Deppe, C., Enríquez Rocha, P., Petersen, J.L., Rangel Salazar, J.L., Segars, K.P. and Wood, K.L. 1999. Great Grey Owl (Strix nebulosa). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. and de Juana, E. (eds), Handbook of the Birds of the World Alive, Lynx Edicions, Barcelona.

IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-3. Available at: www.iucnredlist.org. (Accessed: 07 December 2016).

König, C. and Weick, F. 2008. Owls of the World. Christopher Helm, London.

Lopes, H., Redig, P., Glaser, A., Armien, A. and Wünschmann, A. 2007. Clinical Findings, Lesions, and Viral Antigen Distribution in Great Gray Owls (Strix nebulosa) and Barred Owls (Strix varia) with Spontaneous West Nile Virus Infection. Avian Diseases 51(1): 140-145.

Partners in Flight Science Committee. 2013. Population Estimates Database, version 2013. Available at: http://rmbo.org/pifpopestimates. (Accessed: 09/07/2015).


Citation: BirdLife International. 2016. Strix nebulosa. The IUCN Red List of Threatened Species 2016: e.T22689118A93218931. . Downloaded on 18 November 2017.
Disclaimer: To make use of this information, please check the <Terms of Use>.
Feedback: If you see any errors or have any questions or suggestions on what is shown on this page, please provide us with feedback so that we can correct or extend the information provided