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Location St Helena (to UK), Tristan da Cunha
Central coordinates 12o 41.00' West  37o 18.00' South
IBA criteria A1, A2, A4i, A4ii, A4iii
Area 1,400 ha
Altitude 0 - 511m
Year of IBA assessment 2001

Site description The site comprises the whole of Inaccessible Island as described in the ‘General introduction’.

Key Biodiversity See Box and Table 2 for key species. At least 33 bird taxa are known. Sixteen species of breeding seabirds and four of native landbirds occur. The seabirds include Eudyptes chrysocome moseleyi, Diomedea exulans dabbenena, D. chlororhynchos, Phoebetria fusca, Pterodroma brevirostris, P. mollis, Pachyptila vittata, Procellaria a. conspicillata, Puffinus gravis, P. assimilis, Pelagodroma marina, Fregetta grallaria, Pelecanoides urinatrix, Catharacta antarctica, Sterna vittata and Anous stolidus. It is possible that the three Tristan Island winter breeders, Pterodroma macroptera, P. incerta and Procellaria cinerea, also breed here.Procellaria aequinoctialis conspicillata is entirely restricted to Inaccessible Island when breeding; estimates in 1999 put the population as between 2,500–10,000 individuals and declining.The terrestrial species include Atlantisia rogersi, Nesocichla eremita gordoni (850 pairs, 1990 estimate) Nesospiza acunhae acunhae (2,500 pairs, 1983 estimate) and N. wilkinsi dunnei (200 pairs, 1983 estimate).Non-breeding visitors include Diomedea melanophris, Macronectes giganteus, M. halli, Fulmarus glacialoides, Daption capense, Pachyptila desolata, Puffinus griseus, Oceanites oceanicus, Porphyrula martinica, Calidris fuscicollis, Larus dominicanus, Sterna paradisaea and Hirundo rustica.

Non-bird biodiversity: The only breeding native mammal is Arctocephalus tropicalis. At least 39 species of native terrestrial invertebrates are known. The island is particularly rich in the listroderine weevils, endemic to the Tristan group as a whole.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Eudyptes chrysocome breeding  1990  17,000-27,000 breeding pairs  unknown  A1  Not Recognised 
Tristan Albatross Diomedea dabbenena breeding  1990  2-3 breeding pairs  good  A1  Critically Endangered 
Sooty Albatross Phoebetria fusca breeding  1987  200 breeding pairs  A1, A4ii  Endangered 
Atlantic Yellow-nosed Albatross Thalassarche chlororhynchos breeding  1983  1,100 breeding pairs  A1, A4ii  Endangered 
Puffinus assimilis breeding  1987  5,000-50,000 breeding pairs  A4ii  Not Recognised 
Broad-billed Prion Pachyptila vittata breeding  1987  50,000-500,000 breeding pairs  A4ii  Least Concern 
Soft-plumaged Petrel Pterodroma mollis breeding  1987  5,000-50,000 breeding pairs  A4ii  Least Concern 
Spectacled Petrel Procellaria conspicillata breeding  1999  2,500-9,999 individuals  unknown  A1, A4ii  Vulnerable 
Great Shearwater Ardenna gravis breeding  1987  1,500,000-2,000,000 breeding pairs  A4ii  Least Concern 
Inaccessible Rail Atlantisia rogersi resident  1989  2,500-5,000 breeding pairs  A1, A2, A4i  Vulnerable 
Antarctic Tern Sterna vittata breeding  1983  86 breeding pairs  A4i  Least Concern 
Tristan Thrush Nesocichla eremita resident  1998  present  A1, A2  Near Threatened 
Nesospiza acunhae resident  1998  present  A1, A2  Not Recognised 
Nesospiza wilkinsi resident  1998  present  A1, A2  Not Recognised 
A4iii Species group - seabirds breeding  1987-1990  5,000,000-9,999,999 individuals  unknown  A4iii   
White-faced Storm-petrel Pelagodroma marina breeding  1987  5,000-50,000 breeding pairs  A4ii  Least Concern 
White-bellied Storm-petrel Fregetta grallaria breeding  1987  5,000-50,000 breeding pairs  A4ii  Least Concern 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Gough and Inaccessible Islands World Heritage Site 397,900 protected area contains site 1,400  
Inaccessible Island Wildlife Reserve 1,400 is identical to site 1,400  

Land use

Land-use Extent (% of site)
nature conservation and research -

Further web sources of information 

Alliance for Zero Extinction (AZE) species/site profile. This site has been identified as an AZE due to it containing a Critically Endangered or Endangered species with a limited range.

References Cooper et al. (1995), Fraser (1983, 1989), Fraser and Briggs (1992), Fraser et al. (1983, 1988, 1992, 1994), Olson (1973), Richardson (1984), Rowan (1951), Rowan et al. (1951), Ryan (1998), Ryan and Moloney (in press), Ryan et al. (1990, 1994, 2001), Swales (1996), Wace and Holdgate (1976).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Inaccessible Island. Downloaded from on 24/10/2016

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