Seabird Populations of the Chagos Archipelago, Indian Ocean: An Evaluation of IBA Sites

Indian Ocean seabirds are subject to numerous threats, and populations are thought to be at a fraction of historical levels. We carried out a rapid assessment of the seabird breeding populations of the Chagos Archipelago, a UK Overseas Territory, during early March 2006. We surveyed 26 islands covering the four island groups of the Archipelago. A total of 17 species of breeding seabird were recorded. Since the last survey in 1996, nine species showed reductions in the number of breeding pairs, with brown noddy Anous stolidus and lesser noddy Anous tenuirostris showing reductions of c. 22,000 and c. 27,000 pairs, re- spectively. These reductions, coupled with apparent sooty tern Sterna fuscata colony relocations, are central to our suggested changes to the Important Bird Areas (IBAs) criteria in the Archipelago and we propose two new sites for IBA status. We discuss our findings within a regional conservation context and provide recommendations for the implementa- tion of an annual monitoring scheme of Chagos seabird populations to allow appropriate conservation management.

DOI: 10.1017/S0030605308007217