|
The concept of an extinct species is easy to understand, as it no longer exists. There are simply none left. Most people also understand the concept of a threatened species, but how do we know if a species is threatened or not? There are several different classifications into which a living threatened species or subspecies may be placed (Critically Endangered, Endangered or Vulnerable), and to determine which  classification is the correct one, the species or subspecies must fit at least one of several criteria:
- The population must have declined measurably
- The extent of occurrence must be restricted, with a small population or a fragmented distribution
- The population must be small and declining or with a fragmented distribution
- The population is considered likely to become extinct in the foreseeable future
If a species or subspecies fits any of these criteria, it can be classified as Critically Endangered, Endangered or Vulnerable, depending on certain parameters within each criterion.
Some species or subspecies that are poorly known are occasionally added to the Threatened Bird List as more information about them is discovered through research by organisations such as Birds Australia.
The following lists are derived from the Action Plan for Australian Birds 2000 by Stephen Garnett and Gabriel Crowley.The full texts are available at Environment Australia.
|
Resources 
