Barn owl evaluation
This document describes the Committee on the Status of Species at Risk in Ontario’s evaluation of the barn owl. This evaluation determines whether the species will receive protection under the Endangered Species Act.
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COSSARO Candidate Species at Risk Evaluation Form for Barn Owl (Tyto alba)
Committee on the Status of Species at Risk in Ontario (COSSARO)
Assessed June 2010 by COSSARO as Endangered
Part 1: COSSARO Candidate species at risk evaluation form – June 2010
Barn Owl (Tyto alba)
GRANK – G5
NRANK Canada – N3
COSEWIC – Eastern population: Endangered (May 2000)
SARA – Endangered (Schedule 1) General Status Canada – Sensitive ESA 2007 – Endangered
SRANK – S1
General status Ontario – At Risk
Distribution and status outside Ontario:
Distribution almost worldwide. Two designatable units in Canada, eastern and western.
- Yes. Native in Canada, occurrences in Quebec, Ontario and British Columbia
- Yes. Considered a valid species in all recent taxonomic treatments. No clear genetic answer to question about whether east and west populations are distinct.
One designatable unit in Ontario, two in Canada
- No. Long known as a native bird
Primary criteria (rarity and declines)
1. Global rank
- Not in any category. G5
2. Global decline
- Not in any category.
3. Northeastern North America ranks
THR. (Ranked S1, S2, SH, or SX in 13 of 19 (68%) of Northeastern North American jurisdictions in which it occurs and is ranked. The species is ranked S3 in an additional 6 jurisdictions.)
4. Northeastern north america decline
END. (The Barn Owl is a species of Special Concern in 5 (Vermont, Pennsylvania, New York, Maryland, and Massachusetts), Threatened in 4 (Rhode Island, Ohio, Connecticut, and Ontario), and Endangered in 2 (Michigan and Iowa) northeastern jurisdictions (Appendix 1; Blodget 1989). Based on the number of northeastern jurisdictions where the species is ranked S1 or S2, or is listed as Threatened or Endangered, it appears that Barn Owls are still in decline. Therefore, "Endangered" status is presumed for this criterion in the absence of information regarding population decline from Natural Heritage Programs.
5. Ontario occurrences
END. (Ontario population ≤ 20 mature birds (Badzinski 2007)).
6. Ontario decline
END (Virtually all sites checked in 2008 for which previous (1986 or 2001) population counts are estimates are available, have declined (Table 1 in COSEWIC 2010). Twelve of 25 (48%) Element Occurrence records in the NHIC database are considered extirpated and at least a couple of others have not been recently checked and may be extirpated.)
7. Ontario’s conservation responsibility
- Not in any category (Ontario makes up <5% of the species global range (COSEWIC 2010).)
Secondary criteria (threats and vulnerability)
1. Population sustainability
- Not in any category
2. Lack of regulatory protection for exploited wild populations
- Not in any category (Barn Owls are not migratory, and are protected in Ontario by FWCA and SARA.)
3. Human threats
END. (Loss of nesting habitats (old barns and silos), loss of foraging habitat and mortality along roads are important threats to the survival of Barn Owls in Ontario.)
4. Specialized life history or habitat-use characteristics
END. (The short adult life span, puts Barn Owls at risk, particularly in light of the loss of habitat for nesting and foraging. Although Barn Owls can be prolific breeders, they are not achieving high levels of reproduction in Ontario.)
COSSARO criteria met (primary/secondary)
Endangered – 3/2
Threatened – 1/0
Special concern – 1/0
Barn Owl (Tyto alba)
One of the two Canadian populations occurs in Ontario (consisting of ~20 adult birds), the other is in British Columbia. Although this species has high reproductive potential because they lay large clutches and may reproduce at any time of the year, adults live less than 3 years. Even though in British Columbia and elsewhere in their range these birds regularly use nest boxes, this has not happened in Ontario. In Ontario, birds have suffered from loss of nesting sites (old barns and silos) and foraging habitat (due to the spread of agriculture and succession). There has been no change in the population in Ontario since the last assessment. Changes in land use and farming practices are the main threats to the population in Ontario. This species is Endangered in Ontario.
Badzinski, D.S. 2007. Barn Owl. Pp. 288-289 in Cadman, M.D., D.A. Sutherland, G.G. Beck, D. Lepage, and A.R. Couturier, eds. Atlas of the Breeding Birds of Ontario, 2001-2005. Bird Studies Canada, Environment Canada, Ontario Field Ornithologists, Ontario Ministry of Natural Resources, and Ontario Nature, Toronto, xxii + 706 pp.
Blodget, B.G. 1989. Common Barn-owl. Pp. 81-87 in Proc. Northeast Raptor Management Symposium and Workshop (B. Giron Pendleton, ed.). National Wildlife Federation Scientific and Technical Series No. 13.
COSEWIC 2010. Update Status Report on Barn Owl (Tyto alba) – Eastern Population and Western Population. Committee on the Status of Endangered Wildlife in Canada. Ottawa.
Northeastern North America rank, status and decline
Occurs as a native species in 19 of 29 northeastern jurisdictions S-rank or equivalent information available for 19 of 19 jurisdictions = 100 % S1, S2, SH or SX in 13 of 19 = 68 %
Part 2: Ontario evaluation using COSEWIC criteria
Regional (Ontario) COSEWIC criteria assessment
Criterion A – Decline in total number of mature individuals
Not in any category: no evidence of decline over at least 10 years
Criterion B – Small distribution and decline or fluctuation
Not in any category
Criterion C – Small and declining number of mature individuals
Not in any category
Criterion D – Very small or restricted total population
Endangered (D1) [≤ 20 adults in the population]
Criterion E – Quantitative analysis
No data available
There remains the possibility that vagrant individuals from populations south of Lake Erie may end up in Ontario, but there is no evidence of this having happened in at least 10 years.