Vesper sparrow (Pooecetes gramineus affinis) COSEWIC assessment and status report: chapter 11
Technical Summary
Pooecetes gramineus affinis
Vesper Sparrow affinis subspecies – Bruant vespéral de la sous-espèce affinis
Extent and Area information
Population information
generations, whichever is greater (or specify if for shorter time
period):
(> 1 order of magnitude)?
(>1 order of magnitude)?
Threats (actual or imminent threats to populations or habitats)
- Habitat loss and fragmentation from human development
- Habitat loss from spread of invasive plants
- Increased human disturbance at remaining habitat
- Increased predation pressure associated with increasing urbanization
Quantitative Analysis
Not done
Current Status
COSEWIC: Endangered (2006)
British Columbia CDC: Blue-listed
Status and Reasons for Designation
Status:
Endangered
Alpha-numeric code:
- B1ab(i, ii, iii) +2ab(i, ii, iii);
- C2a(i, ii);
- D1
Reasons for Designation: This songbird, a subspecies of the Vesper Sparrow, is found in Canada only in coastal grasslands in the extreme southwestern corner of British Columbia, where it now breeds only at one site with a population of about 5 pairs. The taxon is declining in the United States as well, where it has a restricted distribution in western Washington and Oregon. Habitat loss is the greatest threat, both through direct destruction of habitat for urban development and through invasion by alien plant species.
Applicability of Criteria
Criterion A: (Declining Total Population): Rate of decline unknown.
Criterion B: (Small Distribution, and Decline or Fluctuation): Met Endangered B1ab(i,ii,iii)+2ab(i,ii,iii) because of its very small extent of occurrence and area of occupancy - only one breeding site - and decline in the number of sites occupied and quality of habitat.
Criterion C: (Small Total Population Size and Decline): Met Endangered C2a(i,ii) because of its low breeding population (< 20 birds) and continuing decline of that population. All the birds occur in this one population.
Criterion D: (Very Small Population or Restricted Distribution): Endangered D1 (<250 individuals)
Criterion E: (Quantitative Analysis): Not done.
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