There is a large amount of information on birds in Antarctica but this has never previously been assembled and analysed to determine exactly where the most significant breeding sites for the avifauna as a whole are.  Such information is essential in order to inform the conservation actions needed to protect them against the range of threats identified in Antarctica.  These include direct disturbance by visitors, disturbance by aircraft or vehicles, exposure to pollutants, ingestion of or fouling by marine debris, competition for prey from fisheries, accidental by-catch on fishing lines or in nets, introduction of disease from other parts of the world and climate change. Recent analyses have identified 204 Important Bird Areas (IBAs) in Antarctica, for all of which detailed site accounts have been compiled. Sites were identified using internationally agreed criteria that have been applied in 200 countries over the past 35 years. The compiled list of IBAs provides a baseline against which change can be measured and conservation actions considered.

The Important Bird Area (IBA) programme was originally established by BirdLife International more than 35 years ago to provide a means of identifying sites of international conservation significance for the world’s birds. To date more than 12,000 IBAs covering over 200 countries have been documented and delineated globally. The current study has, for the first time, assembled and analysed available data on the avifauna of Antarctica (excluding the sub-Antarctic islands) according to the standard IBA criteria to identify and describe those sites that possess characteristics that indicate they are of particular importance to species conservation.

Identifying those areas of Antarctica that are most important for birds has its roots in efforts to compile data on the distribution and abundance of Antarctic bird species undertaken by the Scientific Committee on Antarctic Research (SCAR) Bird Biology Sub-Committee as early as the 1980s. Criteria for selection appropriate to Antarctica were agreed in 2000 in Tokyo, Japan, based on IBA designation criteria established by BirdLife and used elsewhere in the world. SCAR and BirdLife International then held workshops and an initial list of IBAs was identified.

Global site selection categories used were as follows:

• A1: Globally threatened species.
• A2: Restricted range species.
• A3: Biome-restricted assemblages.
• A4: Globally important congregations (with four subcategories).
  - A4i: The site is known or thought to hold, on a regular basis, 1% or more of a biogeographic population of a congregatory waterbird species.
  - A4ii: The site is known or thought to hold, on a regular basis, 1% or more of the global population of a congregatory seabird or terrestrial species.
  - A4iii: The site is known or thought to hold, on a regular basis, at least 20 000 waterbirds, or at least 10 000 pairs of seabirds, of one or more species.
  - A4iv: The site is known or thought to be a bottleneck site where at least 20 000 pelicans and / or storks and / or raptors and/ or cranes pass regularly during spring and / or autumn migration.

In this study, it was clear that categories A2, A3 and A4iv were not applicable.  The sites were evaluated on the basis of whether individual colonies (as identified in source data) met the thresholds for IBA listing. In applying the criteria and recognising the sites, the project undertook consultation with scientists world-wide over a period of several years.

The count for each site is based on totals given in source data for individual colonies. These colonies are represented within the database as points with an associated count. In some cases individual colonies are well-known and defined within a specific location, while in others both the numbers and the spatial delineation of the colony are only poorly defined. In some cases the spatial extent of the colony is unknown. Occasionally populations have been estimated over a number of colonies which may be widely separated (e.g. by up to tens of kilometres), although only a total for the area is given in the source data. In this report the most reliable and recent counts available have been used for the purposes of determining whether a site meets IBA criteria. Where several recent counts were available, for example from both a ground count and from satellite image analysis, both are presented.

Determining the boundaries of the sites proved to be difficult. Particular rules were defined for IBAs that coincide with existing Antarctic Specially Protected Areas or Antarctic Specially Managed Areas because these are distinct, legally agreed areas that have management plans to regulate activities within their boundaries. Where the IBAs lie outside these areas seven different scenarios were used to determine boundaries. For example, where birds triggering an IBA are known or thought to breed on distinct islands within an island group and the island group covers a land area of ≤5 km², the IBA boundary is drawn using the shortest perimeter such that all islands within the group are incorporated into the IBA, adjusting the perimeter where appropriate so that it follows the island coastline.  If new evidence emerges that suggests that IBAs should be grouped into larger units based on alternative criteria, then the analysis could be re-run.

It should be noted that for Emperor Penguins breeding areas are dependent on sea-ice conditions in a given season so that it is recognised that these sites will vary in both size and position from year to year and within any given season.

The list of IBAs presented identifies 204 breeding sites that meet the global IBA criteria in Antarctica (Figure 1). The Site Accounts provided in the full report (Harris et al. 2015) describe for each IBA the bird species present and their numbers, key features of the local environment, other wildlife present, potential conservation issues, and provides references to further data and descriptions. The Site Accounts include maps showing the IBA boundaries in their local context, including prominent physical features, nearby research stations, and protected areas in the vicinity, as well as referencing relevant literature.

Figure 1. 204 Important Bird (breeding) Areas identified across the Antarctic continent and offshore islands.

At this stage the IBA assessment has been made for breeding sites only, and the wider marine foraging areas of birds remain to be addressed.

Of the IBAs that coincide with Antarctic Specially Protected Areas (ASPAs) (Table 1), 27 lie within those ASPAs that have been designated for values mainly or at least in part related to avifauna, three encompass or coincide with ASPAs protected for reasons other than avifauna, such as historic or terrestrial values, while a further three lie on the boundary of a marine ASPA. Two sites that no longer qualify as IBAs are designated ASPAs. Nine IBAs lie within three Antarctic Specially Managed Areas (ASMAs).

The full list of 204 Antarctic IBAs was acknowledged by the Antarctic Treaty Consultative Meeting at its 2015 meeting.  The meeting adopted Resolution 5 (2015) which recommended that governments take account of the recognised IBAs in the planning and conduct of their activities in Antarctica including in the preparation of environmental impact assessments, and requested the Committee for Environmental Protection to provide an update on the extent to which the IBAs are, or should be, represented within the series of Antarctic Specially Protected Areas, in particular those areas that might qualify as “major colonies of breeding native birds”.

Table 1. The location of IBAs that are within ASMAs and ASPAs.