Global IBA Criteria

A1. Globally threatened species

Criterion: The site is known or thought regularly to hold significant numbers of a globally threatened species.

Notes: The site qualifies if it is known, estimated or thought to hold a population of a species categorized by the IUCN Red List as Critically Endangered, Endangered or Vulnerable. Specific thresholds are set for species within each of the threat categories that need to be exceeded at a particular IBA. The list of globally threatened species is maintained and updated annually for IUCN by BirdLife International (

A2. Restricted-range species

Criterion: The site is known or thought to hold a significant population of at least two range-restricted species.

Notes: Restricted-range bird species are those having a global range size less than or equal to 50,000 km2. 'Significant population': it is recommended that site-level populations of at least two restricted-range species should be equal to or exceed 1% of their global population. This criterion can be applied to species both within their breeding and non-breeding ranges.

A3. Biome-restricted species

Criterion: The site is known or thought to hold a significant component of the group of species whose distributions are largely or wholly confined to one biome-realm

Notes: Bioregion-restricted assemblages are groups of species with largely shared distributions which occur (breed) mostly or entirely within all or part of a particular bioregion. Bioregions are defined by the WWF classification of biome-realms. Many biome-realms hold large numbers of species restricted to them, often across a variety of different habitat types; networks of sites must be chosen to ensure, as far as possible, adequate representation of all relevant species. In data-poor areas, knowledge of the quality and representativeness of the habitat types within sites alongside incomplete knowledge of the presence of bioregion-restricted species can be used to inform site selection. Many biome-realms cross political boundaries; where this is so, national networks of sites are selected to ensure that all relevant species in each country are adequately represented in IBAs. Thus biome-realms require that the networks of sites take account of both the geographical spread of the biome-realm and the political boundaries that cross them, as appropriate. Under 'significant component' it is recommended to use 30% of the number of bioregion-restricted species within a biome-realm within a country or five bioregion-restricted species, whichever is greatest.

A4. Congregations

Criterion: The site is known or thought to hold congregations of ≥1% of the global population of one or more species on a regular or predictable basis.

Notes: Sites can qualify whether thresholds are exceeded simultaneously or cumulatively, within a limited period. In this way, the criterion covers situations where a rapid turnover of birds takes place (including, for example, for migratory land birds).