Ardery Island and Odbert Island are situated in the southern part of the Windmill Island group, Vincennes Bay, Budd Coast, Wilkes Land. The islands are located between Sparkes Bay and Hiegel Passage. Odbert Island, the larger of the two, has a steep rocky coast rising to ~100 m and is ~2.5 km long by ~0.8 km wide. Ardery Island is ~1 km long by ~0.5 km wide and rises to ~113 m. Both islands are of granitic composition, are rocky with very little soil material, and are mainly ice-free in the summer. The climate is like to be similar to nearby Casey Station, where the mean annual temperature is around –9.3°C, with mean temperatures for the warmest and coldest months of the year being 0.3°C and -14.9°C respectively, and maxima and minima ranging from 9.2°C to -41°C.
Ardery Island and Odbert Island were specially protected in 1966 primarily for values related to resident breeding fulmarine petrel species, including Antarctic Petrel (Thalassoica antarctica), Southern Fulmar (Fulmarus glacialoides), Cape Petrel (Daption capense) and Snow Petrel (Pagodroma nivea). Ardery Island is the only place where the two subspecies of Snow Petrels (P. n. nivea and P.n. confusa) have been observed together (ASPA No. 103 Management Plan 2010).
The IBA qualifies on the basis of the number of seabirds present and coincides with the boundary of ASPA No. 103.
The nearest permanent station is Casey (AUS), ~10 km to the north on Bailey Peninsula.
Tables 145.1 and 145.2 summarise data on the numbers of pairs for species breeding on Ardery and Odbert islands.
An Adélie Penguin ( Pygoscelis adeliae ) breeding colony is located on the southeastern coast of Odbert Island, and although this species is regularly observed on Ardery Island, they do not breed at this site.
Southern Fulmars nest along the northern and southwestern cliffs and at the eastern extremity of Ardery Island, and nest along the northern and southeastern coastal cliffs of Odbert Island. Antarctic Petrels breed on the northern coast of Ardery Island and in a small group of ~30 pairs near the central northern cliffs of Odbert Island. Cape Petrels breed on the northern and northeastern coasts of Ardery Island and on the northern and southeastern coasts of Odbert Island. Snow Petrels breed mostly on the higher slopes throughout both islands. Wilson's Storm-petrels ( Oceanites oceanicus ) also breed across both islands, and are present in rocky areas with niches suitable for nest-building. South Polar Skuas ( Catharacta maccormicki) breed close to petrel colonies on Ardery Island, whereas on Odbert Island they breed close to the Adélie Penguin colony (ASPA No. 103 Management Plan 2010).
The Southern Giant Petrel ( Macronectes giganteus ) has been recorded at the islands, although does not breed (ASPA No. 103 Management Plan 2010). More detailed descriptions of the environment and breeding sites on Ardery and Odbert islands may be found in the management plan for ASPA No.103.
Non-bird biodiversity: Weddell Seals (Leptonychotes weddellii) are reported on the sea ice that forms around Ardery Island and Odbert Island (ASPA No. 103 Management Plan 2010).
BirdLife International (2019) Important Bird Areas factsheet: Ardery Island / Odbert Island. Downloaded from http://www.birdlife.org on 20/04/2019.