State of the world's birds

The Important Bird Area (IBA) programme is being extended to the oceans. This requires a number of refinements to the criteria by which IBAs are identified and delimited, in order to capture four aspects of seabird distribution:

1. Foraging areas around seabird breeding colonies. These include coastal foraging and maintenance areas and are contiguous with existing IBAs—identified for the breeding colonies themselves—and, as a result of extending boundaries seaward, are likely to be integrated with them. These seaward extensions are, where possible, colony- and/or species-specific, based on known or estimated foraging and maintenance ranges.
2. Coastal congregations of non-breeding seabirds. These include areas of shallow water used, for example, by foraging and/or moulting sea-ducks.
3. Migration bottlenecks. These include places through or around which more than threshold numbers of seabirds pass regularly, such as straits, headlands etc.
4. Pelagic concentrations. These cover foraging areas where pelagic species concentrate, such as over shelf-breaks areas and on eddies and upwellings; such areas are often remote from breeding colonies.

Analyses of existing datasets have shown that some 2,156 IBAs, across 159 countries and territories may be considered marine on the basis of the seabird breeding colonies they hold (Howgate and Lascelles 2007, analysis of data held in BirdLife’s World Bird Database). Data on foraging distances of seabirds are being compiled and, where possible, combined with data on habitat and topography, to provide guidance on establishing revised seaward boundaries for these sites, where appropriate. An example of how this approach is being developed is shown in the accompanying figure.