Biology Department

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IUCN Red List Categories

The International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species provides taxonomic, conservation status and distribution information on taxa that have been globally evaluated using the IUCN Red List Categories and Criteria. The IUCN Red List Categories and Criteria are an objective and widely accepted system for classifying species at high risk of extinction. BirdLife International coordinates the assessment of the status of the world's birds using these categories and criteria and, as the official Red Listing Authority for birds for the IUCN Red List, submits this information to be included on the IUCN Red List along with that of other animals and plants. The categories, including the three globally threatened categories (Critically Endangered, Endangered and Vulnerable) are outlined below.

EXTINCT (EX)

A species is Extinct when there is no reasonable doubt that the last individual has died. A species is presumed Extinct when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the species's life history.

EXTINCT IN THE WILD (EW)

A species is Extinct in the Wild when it is known only to survive in captivity or as a naturalized population (or populations) well outside the past range. A species is presumed Extinct in the Wild when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the species's life history.

CRITICALLY ENDANGERED (POSSIBLY EXTINCT) CR (PE)

This is not an official category of the IUCN Red List, but a tag applied by BirdLife (and under review by the IUCN Red List) to identify those Critically Endangered species (see definition below) 'that are likely to be extinct, but for which there is a small chance that they may still be extant, and hence they should not be listed as Extinct until local or unconfirmed reports have been discounted, and adequate surveys have failed to find any individuals' (see below for further details).

CRITICALLY ENDANGERED (CR)

A species is Critically Endangered when the best available evidence indicates that it meets any of the criteria A to E for Critically Endangered (see IUCN Red List Criteria) and it is therefore considered to be facing an extremely high risk of extinction in the wild.

ENDANGERED (EN)

A species is Endangered when the best available evidence indicates that it meets any of the criteria A to E for Endangered (see IUCN Red List Criteria), and it is therefore considered to be facing a very high risk of extinction in the wild.

VULNERABLE (VU)

A species is Vulnerable when the best available evidence indicates that it meets any of the criteria A to E for Vulnerable (see IUCN Red List Criteria), and it is therefore considered to be facing a high risk of extinction in the wild.

NEAR THREATENED (NT)

A species is Near Threatened when it has been evaluated against the criteria but does not qualify for Critically Endangered, Endangered or Vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category in the near future.

LEAST CONCERN (LC)

A species is Least Concern when it has been evaluated against the criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened. Widespread and abundant species are included in this category.

DATA DEFICIENT (DD)

A species is Data Deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status. A species in this category may be well studied, and its biology well known, but appropriate data on abundance and/or distribution are lacking. Data Deficient is therefore not a category of threat.

?- Not listed by IUCN

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