as a whole and for all of its species in each range state. A4. Congregations i. This applies to 'waterbird' species as defined by Delaney and Scott and is modelled on criterion 6 of the Ramsar Convention for identifying wetlands of international importance. Depending upon how species are distributed, the 1% thresholds for the biogeographic populations may be taken directly from Delaney & Scott, they may be generated by combining flyway populations within a biogeographic region or, for those for which no quantitative thresholds are given, they are determined regionally or inter-regionally, as appropriate, using the best available information. ii. This includes those seabird species not covered by Delaney and Scott (2002). Quantitative data are taken from a variety of published and unpublished sources. iii. This is modeled on criterion 5 of the Ramsar Convention for identifying wetlands of international importance. The use of this criterion is discouraged where quantitative data are good enough to permit the application of A4i and A4ii. iv. The site is known or thought to exceed thresholds set for migratory species at bottleneck sites. The assessment by expert individuals is however not entirely reliable and a study in South America found that the coverage needed for at-risk bird conservation as chosen by computational algorithms rarely overlapped with IBAs and suggested that such methods should be used to complement expert driven IBA site choices. See also Biodiversity Biodiversity hotspot Important Plant Areas Key Biodiversity Areas Protected areas References Bird conservation BirdLife International