Greater sage-grouse (Centrocercus urophasianus) COSEWIC assessment and status report: chapter 12
Technical Summary : Greater Sage-Grouse urophasianus subspecies
Centrocercus urophasianus urophasianus
Greater Sage-Grouse urophasianus subspecies – Tétras des armoises de la sous-espèce urophasianus
Range of Occurrence in Canada:
Alberta, Saskatchewan
Extent and Area Information
Extent of occurrence (EO) (km²) [Aldridge and Brigham (2003) based on radio-telemetry and lek locations] :
6,000 km²
Specify trend in EO :
Declining (6% of former range)
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km²) [extrapolated from Aldridge and Boyce 2007] :
1, 800 km²
Specify trend in AO :
Declining
Are there extreme fluctuations in AO?
No
Number of known or inferred current locations :
15
Specify trend in # :
Declining; 50% loss of leks in last 10 years
Are there extreme fluctuations in number of locations?
No
Specify trend in area, extent or quality of habitat :
Declining
Population Information
Generation time (average age of parents in the population) :
Ca. 3 years
Number of mature individuals :
450-667
Total population trend:
Declining
% decline over the last/next 10 years or 3 generations.
- 42% (1996-2006)
- 83-88% (1988-2006)
Are there extreme fluctuations in number of mature individuals?
No
Is the total population severely fragmented?
No
Specify trend in number of populations :
Not applicable
Are there extreme fluctuations in number of populations?
No
List populations with number of mature individuals in each:
Threats (actual or imminent threats to populations or habitats)
- Habitat loss and fragmentation through conversion of rangeland to crops and oil and gas development
- Habitat degradation from livestock overgrazing
- Direct disturbance to lekking and nesting birds
- Alteration in hydrology through construction of dugouts, dams and reservoirs
- Disease (West Nile Virus)
- Loss of genetic variability
Rescue Effect (immigration from an outside source)
Status of outside population(s)?
USA: [Montana] Populations north of the Milk River are declining; stable south of the Milk River
Is immigration known or possible?
Yes
Would immigrants be adapted to survive in Canada?
Yes
Is there sufficient habitat for immigrants in Canada?
Declining
Is rescue from outside populations likely?No; declining populations and habitat in northern Montana
Quantitative Analysis
Not done
Current Status
COSEWIC: Endangered (2000 and 2008)
Status and Reasons for Designation
Status: Endangered
Alpha-numeric code: A2b, C1
Reasons for Designation: This large grouse is restricted to sagebrush grasslands in southern Alberta and Saskatchewan and has suffered significant population declines (42% over the last 10 years, 88% since 1988). The number of leks (male display sites) has decreased by 50% in the last 10 years and there are now less than a thousand breeding birds in the population. Causes for the decline are largely due to the loss, fragmentation and degradation of its native grassland habitats through oil and gas exploration, overgrazing and conversion to crops.
Applicability of Criteria
- Criterion A (Declining Total Population): Meets Endangered A2b based on estimated population trend and declining number of leks.
- Criterion B (Small Distribution, and Decline or Fluctuation): Has small distribution, but is not severely fragmented and number of locations 15.
- Criterion C (Small Total Population Size and Decline): Meets Endangered C1 if present population decline continues.
- Criterion D (Very Small Population or Restricted Distribution): Meets Threatened D1
- Criterion E (Quantitative Analysis): Not done.