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COSEWIC assessment and update status report on the Burrowing Owl in Canada

Technical Summary

Athene cunicularia

Burrowing Owl

Chevêche des terriers

Range of Occurrence in Canada: AB, BC, SK, MB (essentially extirpated in BC and MB)


Extent and Area Information

Extent of occurrence (EO) (km2)ca. 160 000 km2
specify trend (decline, stable, increasing, unknown)Decline
are there extreme fluctuations in EO (> 1 order of magnitude)?No
area of occupancy (AO) (km2)ca. 5 000 to 10 000 km2
specify trend (decline, stable, increasing, unknown)Decline
are there extreme fluctuations in AO (> 1 order magnitude)?No
number of extant locationsNot applicable
specify trend in # locations (decline, stable, increasing, unknown) 
are there extreme fluctuations in # locations (>1 order of magnitude)? 
habitat trend: specify declining, stable, increasing or unknown trend in area, extent or quality of habitatDeclining


Population Information

generation time (average age of parents in the population) (indicate years, months, days, etc.)2-3 years
number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values)ca. 800-1600
total population trend: specify declining, stable, increasing or unknown trend in number of mature individualsDeclining
if decline, % decline over the last/next 10 years or 3 generations, whichever is greater (or specify if for shorter time period)

combined data from Alberta, Saskatchewan and Manitoba.
ca. 90% through 1990s;
ca. 57% 1994-2004
are there extreme fluctuations in number of mature individuals (> 1 order of magnitude)?No
is the total population severely fragmented (most individuals found within small and relatively isolated (geographically or otherwise) populations between which there is little exchange, i.e., < 1 successful migrant / year)?No
list each population and the number of mature individuals in each 
specify trend in number of populations (decline, stable, increasing, unknown) 
are there extreme fluctuations in number of populations (>1 order of magnitude)? 


Threats (actual or imminent threats to populations or habitats) [add rows as needed]

- Loss, fragmentation, and degradation of breeding, migration and wintering habitat
- Reduced immigration from neighbouring U.S. populations
- Increased predation on adults and young
- Poor reproductive success in most years, preceding population decreases in the next year


Rescue Effect (immigration from an outside source): Very low; habitat loss is major source of decline

does species exist elsewhere (in Canada or outside)?Yes
status of the outside population(s)?Declining
is immigration known or possible?Yes
would immigrants be adapted to survive here?Yes
is there sufficient habitat for immigrants here?Declining


Quantitative Analysis

 


Current Status

COSEWIC: Endangered (2001, 2006)


Status and Reasons for Designation

Status:
Endangered
Alpha-numeric code:
A2bc; C1
Reasons for Designation:
This grassland owl has suffered significant declines across its North America range; Canadian populations declined 90% in the 1990s and the species is essentially extirpated from British Columbia and Manitoba. This population decline slowed somewhat between 1994 and 2004, but remained at approximately 57%. The true cause or causes of this widespread decline remain unknown.


Applicability of Criteria

Criterion A (Declining Total Population):
Endangered A2bc; population has declined by about 57% in last three generations.
Criterion B (Small Distribution, and Decline or Fluctuation):
population not fragmented or fluctuating
Criterion C (Small Total Population Size and Decline):
Met Endangered C1; population less than 2000 and decline likely to continue.
Criterion D (Very Small Population or Restricted Distribution):
Not applicable; population and AO/EO too large
Criterion E (Quantitative Analysis):
Not done.