An Important Bird and Biodiversity Area (IBA) is an area identified using an internationally agreed set of criteria as being globally important for the conservation of bird populations.
IBA was developed and sites are identified by BirdLife International. There are over 13,000 IBAs worldwide. These sites are small enough to be entirely conserved and differ in their character, habitat or ornithological importance from the surrounding habitat. In the United States the Program is administered by the National Audubon Society.
Often IBAs form part of a country’s existing protected area network, and so are protected under national legislation. Legal recognition and protection of IBAs that are not within existing protected areas varies within different countries. Some countries have a National IBA Conservation Strategy, whereas in others protection is completely lacking.
In 1985, following a specific request from the European Economic Community, Birdlife International drew up a list of sites to be protected as a matter of priority. In 1989, a repertoire of IBAs of Europe was released.
At first the official name of this type of site was Important Bird Area, hence the acronym IBA, then at the BirdLife World Congress held in Canada in 2014 it was decided to adopt the name Important Bird and Biodiversity Area, without changing the acronym.
Why apply criteria (IBAs)
The selection of Important Bird and Biodiversity Areas (IBAs) is achieved through the application of quantitative ornithological criteria, grounded in up-to-date knowledge of the sizes and trends of bird populations. The criteria ensure that the sites selected as IBAs have true significance for the international conservation of bird populations, and provide a common currency that all IBAs adhere to, thus creating consistency among, and enabling comparability between, sites at national, continental and global levels.
It is crucial to understand why a site is important, and to do this it is necessary to evaluate its international significance in terms of the presence and abundance of species that occur there, year round or seasonally. Historically, IBA site selection criteria were developed at the global level and for some regions at sub-global levels, including region (Europe and Middle East) and sub-region (European Union, South Africa and the Caribbean). These criteria were recently revised in consultation with our Regional Coordinators, and adopted in 2020. The following pages provide a summary of these revised IBA criteria.
A main aim of the IBA Program of BirdLife International is to secure the long-term conservation of sites that are of significant importance for birds and biodiversity.
The provision of robust bird data and the application of scientific criteria to identify IBA trigger species are essential for the identification of IBAs. Ongoing and regular up-dates permit not only the assessment of changes in species’ numbers but also an examination of how these changes impact on the overall importance of the site.
Together with the implementation of the IBA Monitoring Protocol that assesses the state, the extent of pressures and the responses implemented (arising actions, management etc.), help to interpret these changes and to guide the management and conservation of the area.
There are more than 13,000 IBAs identified so far through the application of the IBA criteria and this information is stored in the World Database of Key Biodiversity Areas (WDKBA) and is available on the BirdLife Data Zone and on the Key Biodiversity Areas Website. The more specific, quantitative and comprehensive is the information available on IBAs, with links showing the fulfilment of obligations laid out in various international conventions, the stronger is the case for protection.
To this end, the criteria build upon existing international legal instruments such as the EC Birds Directive, which obliges the designation of Special Protection Areas in the European Union, and the Ramsar Convention under which contracting parties must designate at least one Ramsar Site (wetland of international importance) in their territory. IBAs form a subset of Key Biodiversity Areas (KBAs) that have been embedded in various international agreements and safeguard mechanisms and serve as indicators for the biodiversity policy framework of the Convention on Biological Diversity (CBD) and the Sustainable Development Goals (SDGs).
Click on any of the pages below to review the more detailed descriptions of the relevant IBA criteria. Detailed guidelines can be downloaded here.
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 (www.birdlife.org/datazone/species).
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.
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).
Regional IBA criteria
B1: Species of conservation concern
B1a: Globally Near Threatened species
Criterion: The site regularly holds significant numbers of a Near Threatened species (NT).
Notes: Near Threatened species were included in the previous version of criterion A1, but they no longer trigger sites of global importance. This criterion is applicable globally.
B1b: Species with an unfavourable conservation status in the region
Criterion: The site is one of the ‘n’ most important in a country for a species with an unfavourable conservation status in the region, and for which the site-protection approach is thought to be appropriate
Notes: Formerly criterion B2. This criterion is only applicable in Europe and the Middle East.
B2: Species with most of their range restricted to a region
B2a: Species with a favourable conservation status but concentrated in the region
Criterion: The site is one of the ‘n’ most important in a country for a species with a favourable conservation status in a region, but with its global range concentrated in that region, and for which the site-protection approach is thought to be appropriate.
Notes: Formerly criterion B3. This criterion is only applicable in Europe and the Middle East.
B3: Regionally important congregations
B3a: Regionally important congregations – biogeographical populations
Criterion: The site is known or thought to hold, on a regular basis, >= 1% of a biogeographic or other distinct population of a congregatory waterbird, breeding seabird or other species.
Notes: This criterion is a unification of former criteria A4i, B1i, B1ii & B1iii (Europe), B1i & B1ii (Middle East)
B3b: Regionally important congregations – multi-species aggregations
Criterion: The site is known or thought to hold, on a regular basis, >= 20,000 waterbirds or >= 6,700 pairs of seabirds of one or more species.
Notes: Formerly part of criterion A4 (A4iii).
B3c: Regionally important congregations – bottleneck sites
Criterion: Site known or thought to exceed thresholds set for migratory species at bottleneck sites.
Notes: This criterion is a unification of former criteria A4iv & B1iv (Europe) and B1iv (Middle East).
Sub-regional IBA Criteria
C: European Union
C1. Species of global conservation concern
Criterion: The site regularly holds significant numbers of a globally threatened species, or other species of global conservation concern.
C2. Concentrations of a species threatened at the European Union level
Criterion: The site is known to regularly hold at least 1% of a flyway population or of the EU population of a species threatened at the EU level (listed on Annex I and referred to in Article 4.1 of the EC Birds Directive).
C3. Congregations of migratory species not threatened at the EU level
Criterion: The site is known to regularly hold at least 1% of a flyway population of a migratory species not considered threatened at the EU level (as referred to in Article 4.2 of the EC Birds Directive) (not listed on Annex I).
C4. Large congregations- multi-species aggregations
Criterion: The site is known to regularly hold at least 20,000 migratory waterbirds and/or 10,000 pairs of migratory seabirds of one or more species.
C5. Large congregations – bottleneck sites
Criterion: The site is a ‘bottleneck’ site where at least 5,000 storks (Ciconiidae) and/or at least 3,000 raptors (Accipitriformes and Falconiformes) and/or 3,000 cranes (Gruidae) regularly pass on spring or autumn migration.
C6. Species threatened at the European Union level
Criterion: The site is one of the five most important in the European region (NUTS region) in question for a species or subspecies considered threatened in the European Union (i.e. listed in Annex I of the EC Birds Directive).