Original criteria and definitions used in species status assessments 1999 to 2001

The revised criteria that are currently in use by Committee on the Status of Endangered Wildlife in Canada (COSEWIC) (since November 2001) are available here.

A. Declining Total Population
  Endangered Threatened
Population decline rate of: ≥ 50% ≥ 20%

using either


(1) population reduction observed, estimated, inferred, or suspected in the past 10 years or 3 generations, whichever is longer, based on any combination of a-e below.
(2) population decline projected or suspected within in the next 10 years or 3 generations, whichever is longer, based on any combination of b-e below.
a. direct observation
b. an index of abundance appropriate for the taxon
c. a decline in area of occupancy, extent of occurrenceand/or quality of habitat
d. actual or potential levels of exploitation
e. the effects of introduced taxa, hybridisation, pathogens, pollutants, competitors or parasites
B. Small Distribution and Decline or Fluctuation
  Endangered Threatened
Either extent of occurrence < 5,000 km2 < 20,000 km2
or area of occupancy < 500 km2 < 2,000 km2
and any 2 of the following 3:
(1) either severely fragmented: or known to exist at # locations (isolated populations with a reduced probability of recolonization, if once extinct)
≤ 5 ≤ 10
(2) continuing decline in any of the following: any rate any rate
a. extent of occurrence
b. area of occupancy
c. area, extent and/or quality of habitat
d. number of locations or populations
e. number of mature individuals
(3) fluctuating in any of the following: > 1 order of magnitude > 1 order of magnitude
a. extent of occurrence  
b. area of occupancy  
c. number of locations or populations
d. number of mature individuals
C. Small Total Population Size and Decline
  Endangered Threatened
Number of mature individuals < 2,500 < 10,000
and 1 of the following 2:    
(1) rapid decline rate of at least 20% in 5 years or 2 generations 10% in 10 years or 3 generations
(2) continuing decline and any rate any rate
either (a) fragmentation all populations ≤ 250 all populations ≤ 1,000
or (b) all individuals in a single population    
D. Very Small or Restricted
Either: Endangered Threatened
(1) # of mature individuals < 250 < 1,000
or (2) population is susceptible (not applicable) area of occupancy <100 km²
or # of locations <5
E. Quantitative Analysis
  Endangered Threatened
Indicating the probability of extinction in the wild to be at least: 20% in 20 years or 5 generations 10% in 100 years

Special Concern:

  • Those species that are particularly sensitive to human activities or natural events but are not endangered or threatened species.

Examples of reasons why a species may qualify for "Special Concern":

  • A species that is particularly susceptible to a catastrophic event (e.g., a large seabird population near oil tanker route)
  • A conservation dependent species that would likely become at risk if not for active protection and management (e.g., a fish or mammal species protected from over-harvest)
  • A recovering species, no longer qualifying for risk categories but not yet clearly secure, or subject to resumption of threat in future

Examples of reasons why a species may not qualify for "Special Concern":

  • Rarity alone in the absence of recognized threat
  • Threat with little possibility of serious harm (e.g., large, fecund population subject to harvest)

Definitions and abbreviations

Alien species: any species that does not qualify as a Canadian native (indigenous) species, including exotic, non-native, non-indigenous, and invasive species.

Area of occupancy: the area (expressed in km2) within a species’ extent of occurrence which is occupied by the species, excluding cases of vagrancy. The measure reflects the fact that a species will not usually occur throughout the area of its extent of occurrence, which may, for example, contain unsuitable habitats. The area of occupancy is the smallest area essential at any stage to the survival of the existing total population of a species. The size of the area of occupancy will be a function of the scale at which it is measured and should be at a scale appropriate to relevant biological aspects of the species. It should be measured on grid squares (or equivalents) which are sufficiently small.

Assessment Categories: designations of the status of species, including: Extinct (X), Extirpated (XT), Endangered (E), Threatened (T), Special Concern (SC), Data Deficient (DD), Not At Risk (NAR).

Best Available Information: information from all sources that are pertinent to the status of the species’ life history and the conservation status of the species including scientific, local and/or traditional information.

CESCC: Canadian Endangered Species Conservation Council

CITES: Convention on International Trade in Endangered Species

COSEWIC: Committee on the Status of Endangered Wildlife in Canada

CDC: Conservation Data Centre (in some provinces also referred to as Natural Heritage Information Centre)

CWDC: Canadian Wildlife Directors Committee

CWS: Canadian Wildlife Service of Environment and Climate Change Canada

Data Deficient (DD): a species for which there is insufficient scientific information to support status designation.

DFO: the federal Department of Fisheries and Oceans

Endangered (E): a species facing imminent extirpation or extinction.

Endangered Species List (Canadian Endangered Species List): includes those species (including subspecies and nationally significant populations) designated "endangered" or "threatened" by COSEWIC to date.

Extent of occurrence: the area (expressed in km2) contained within the shortest continuous imaginary boundary which can be drawn to encompass all the known, inferred or projected sites of present occurrence of a taxon, excluding cases of vagrancy. It can often be measured by the minimum convex polygon that contains all the sites of occurrence. The measure may exclude discontinuities or disjunctions within the overall distribution of a species (e.g., large areas of obviously unsuitable habitat), in which case the extent of occurrence may be composed of two (or more) convex polygons.

Extinct (X): a species that no longer exists.

Extirpated (XT): a species no longer existing in the wild in Canada, but occurring elsewhere.

Federal Biosystematics Partnership: a collaborative endeavour of Agriculture and Agri-food Canada, the Canadian Museum of Nature, Fisheries and Oceans Canada, Environment and Climate Change Canada and Natural Resources Canada to ensure that the importance of biosystematics is recognized, emphasized and supported and that biosystematics is used effectively in Canada.

Fragmentation: most individuals found within small and relatively isolated (geographically or otherwise) populations between which there is little exchange (i.e., < one successful migrant per year).

Generation time: the average age of parents in the population. This is greater than the age at sexual maturity or first breeding, except in species where individuals breed only once.

IUCN: World Conservation Union (formerly known as the International Union for the Conservation of Nature).

Location: a geographically distinct area where a group of individuals of a species is (or has been) found. The total population or a population may comprise a number of sites.

Mature individuals (number of): individuals known, estimated or inferred to be capable of reproduction. In fluctuating populations, use the minimum number. Where possible, estimate the effective total population size. Exclude individuals that are sexually mature but unable to reproduce because of lack of mates, etc. Reproducing units within a clone should be counted as individuals except where such units are unable to survive on their own (e.g., corals). In the case of species that lose all or part of their mature individuals at some point in their life cycle (e.g., annuals, fish that die off after spawning), the estimate should be made at the time when mature individuals are available for breeding.

Nationally significant population: any group within a biological species or subspecies that is recognized as a distinct entity for separate status designation by COSEWIC. Refer to the Guidelines for Listing Nationally Significant Populations for more information.

Native species: an indigenous species that occurs in Canada naturally, or a species that occurred in North America naturally and expanded its range into Canada on its own, has produced viable populations, and persisted in Canada for at least 50 years. Species recently discovered in Canada will be considered native if there is convincing evidence that they were historically native (even if there is no record of their presence for at least 50 years or if there is no data showing they produced viable populations).

Non-government scientific expert: an expert in wildlife conservation who is not a federal, provincial or territorial government employee.

Not at Risk (NAR): a species that has been evaluated and found to be not at risk.

Observer: a person who asks and receives permission to be present at, or who has been invited to, all or part of COSEWIC’s deliberations.

Population (as per technical summary): a geographically or otherwise distinct group (a portion of the total population) of interbreeding individuals which has little exchange of individuals with other such groups (populations) - typically one successful migrant individual or gamete per year or less. (see also Nationally Significant Population and Total Population).

Range jurisdictions: provincial/territorial governments, Wildlife Management Boards, and federal government departments (Environment, Heritage (Parks Canada), Fisheries and Oceans, Biosystematics Partnership) responsible for the conservation and management of species.

Special Concern (SC): a species of special concern because of characteristics that make it particularly sensitive to human activities or natural events.

Species (Biological): a group of organisms of common ancestry that normally are able to reproduce only among themselves and that are usually geographically distinct. A species is the highest rank in the taxonomic hierarchy wherein member individuals may be able to interbreed and share a common evolutionary origin. (see also Species (COSEWIC)).

Species (COSEWIC): an indigenous species, subspecies, variety or geographically defined population (as per "COSEWIC Population Guidelines") of wild fauna and flora. (see also Species (Biological)).

Species at Risk List: all COSEWIC designations to date of species (including subspecies and nationally significant populations) in all COSEWIC categories.

Species expert (COSEWIC): a species expert is a person who has a high level of scientific, traditional or local knowledge of a taxonomic group or geographical area and meets the requirements specified in the Qualifications for COSEWIC Membership.

Status assessment: the act of assessing the risk of extinction or extirpation from Canada, and assigning the species to a risk category, if appropriate.

Status report: a comprehensive technical report that compiles and analyzes the best available information on a species’ status in Canada and indicates the threats to that species. (See also Updated status report).

SSG: Species Specialist Group

Threatened (T): a species likely to become endangered if limiting factors are not reversed.

TNC: The Nature Conservancy (US)

Total population (as per technical summary): the total number of mature individuals of the taxon in Canada. For plants that form clonal colonies, the number of these should be estimated if possible; otherwise, the total population (can be composed of several populations) should be given as the number of stems and clearly indicated as such to avoid all possible confusion with the number of individuals (see also Population and Nationally Significant Population).

Update status report: a comprehensive technical report that updates the best available information on a species’ status, focusing on changes in populations and habitats.

Wildlife: wildlife should mean all wild life: wild mammals, birds, reptiles, amphibians, fishes, invertebrates, plants, fungi, algae, bacteria and other wild organisms.

About us

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) is an independent advisory panel to the Minister of Environment and Climate Change Canada that meets twice a year to assess the status of wildlife species at risk of extinction. Members are wildlife biology experts from academia, government, non-governmental organizations and the private sector responsible for designating wildlife species in danger of disappearing from Canada.

COSEWIC secretariat

Canadian Wildlife Service
Environment and Climate Change Canada
351 St. Joseph Blvd, 16th floor
Gatineau QC K1A 0H3

Email: ec.cosepac-cosewic.ec@canada.ca