The AZE used three basic criteria to identify critical sites in need of immediate protection, endangerement, irreplaceability, and discreteness.
They defined these criteria as follows:
- endangerment: Site contains at least one endangered or critically endangered species (as designated by the IUCN Red List of Threatened Species.
- irreplaceability: Site is the sole area where an endangered or critically endangered species occurs and a significant portion of the population resides there or relies on the site for breeding or wintering.
- discreteness: Site has a definable boundary within which its habitats, biological communities, or management issues are discrete or distinguishable from the surrounding areas.
There are 794 endangered species that live within the sites identified by the AZE's study including species such as the Maui parrotbill (Pseudonestor xanthophrys), whooping crane (Grus americana), golden-crowned sifaka (Propithecus tattersalli), Rodrigues flying fox (Pteropus rodricensis), Worthen's sparrow (Spizella wortheni), and the indigo-winged parrot (Hapalopsittaca fuertesi).
The AZE is made up of conservation organizations from around the world and includes some of the most active participants in species protection today:
- American Bird Conservancy
- BirdLife International
- Conservation International
- Island Conservation and Ecology Group
- National Audubon Society
- Wildlife Conservation Society
Photo © Fundación ProAves