The status codes used in GRIN are based largely on the categories proposed by the IUCN (1986) and adopted by BirdLife International in their Threatened birds of the world (2000), where fuller details are provided on the criteria used to define them. The categories are as follows:

Extinct: It is known for certain that the last individual died.

Extinct in wild: Species surviving only in captivity.

Critically endangered: Species facing imminent extinction. Species placed in this category here may be represented by less than 10 living individuals.

Endangered: Species facing a high risk of extinction in the near future without human intervention.

Vulnerable: Species facing a high risk of extinction the mid-term future, given present trends in population declines and threats. This term is generally equivalent to "threatened," a category used in many other classifications.

Near Threatened: Species not in trouble at the moment, but which require some level of management to maintain healthy populations. Equivalent to "Conservation Dependent" in other classifications..

Lower risk: Species which are not at risk at the species level, although they may include subpopulations that are experiencing problems at regional or local levels.

Data deficient: Species for which too few data are available to adequately assess their status. Following further study, many of these may prove to be Conservation Dependent or Vulnerable.