Which species are assessed
The committee assesses any Ontario species that may be experiencing declines, based on research by government staff or reports from other sources. It can also reassess any species already listed as at risk.
The committee must also put on their list for assessment any plant or animal native to Ontario that has been classified as at risk by its national counterpart, the Committee on the Status of Endangered Wildlife in Canada.
See the list of species that have been assessed and classified by COSSARO.
See what species COSSARO will consider next.
How species are classified
The committee uses the best available scientific information, including community knowledge or Indigenous Traditional Knowledge, to determine whether a plant or animal should be classified as at risk. The committee usually meets twice a year.
When a species is classified as at risk, the classification applies throughout Ontario, unless otherwise noted. In some cases, different geographic populations of the same species face different threats, and are classified separately.
See the document outlining the categories and criteria for status assessment used by the Committee on the Status of Species at Risk in Ontario (COSSARO).
Categories of at risk status
The committee classifies the species into categories based on the degree of risk they face.
Species at risk are classified in 1 of 4 categories:
Extirpated
Lives somewhere in the world, and at one time lived in the wild in Ontario, but no longer lives in the wild in Ontario.
Endangered
Lives in the wild in Ontario but is facing imminent extinction or extirpation.
Threatened
Lives in the wild in Ontario, is not endangered, but is likely to become endangered if steps are not taken to address factors threatening it.
Special concern
Lives in the wild in Ontario, is not endangered or threatened, but may become threatened or endangered due to a combination of biological characteristics and identified threats.
A species may also be designated by the committee as Not at Risk, if it does not meet the criteria for any of the above categories or, as Data Deficient if there is not enough information to make a decision as to its status.
What happens after a species is assessed
COSSARO submits a report on its work (including the classification of each species assessed) to the Minister between January 1 and 31 of each year. In addition to annual reporting, the committee may submit a report classifying a species to the Minister at any time as described in the Species Conservation Act, 2025 . The Lieutenant Governor in Council may then make a regulation listing the species classified as Extirpated, Endangered or Threatened on the Protected Species in Ontario (PSO) List regulation [ O. Reg. 60/26] Once the regulation has been changed, the species is protected based on its COSSARO classification. Please visit the Ontario government website for further information about how species at risk are classified
See complete list of protected species in Ontario
Species assessment reports
Species assessments reports are detailed technical documents that contain information such as the distribution, population size, and threats. Please note that species assessed prior to December 2013 were classified according to COSSARO’s previous criteria. For further information and/or access to species reports from before 2013 please contact us at COSSAROSecretariat@ontario.ca.
This searchable table includes the species assessed by COSSARO from 2013 – 2026, including current status, a link to COSSARO’s assessment report, and a link to the Ontario government species page (if applicable).
- END
- – Endangered
- THR
- – Threatened
- EXP
- – Extirpated
- SC
- – Special Concern
- NAR
- – Not at Risk
- DD
- – Data Deficient
- EXT
- – Extinct
Report a species sighting
If you observed a species and would like to report it, please visit the how to report a rare species sighting page on Ontario.ca.