Site description (2015 baseline)
Half Moon Island is a rocky island lying in Moon Bay, 2 km north of Livingston Island, South Shetland Islands. Raised cobble beaches line the south and central shorelines, while steep scree slopes lead to a low summit at the north of the island. East-facing slopes are typically snow-covered. The IBA qualifies on the basis of the South Polar Skua (Catharacta maccormicki) colony present and comprises the entire island.
Several moss and lichen species and the native Antarctic Hairgrass (Deschampsia antarctica) are found on Half Moon Island (ATS Visitor Site Guidelines, Half Moon Island).
Cámara Station (ARG) (summer-only) is located in the southern part of Half Moon Island and has capacity for ~36 people (COMNAP, Antarctic Facilities, accessed 24/08/2010).
South Polar Skua breed at several locations on Half Moon Island, mostly in the north, with 103 pairs recorded in the 1995-96 (Garcia Esponda et al. 2000). Approximately 2094 pairs of Chinstrap Penguin (Pygoscelis antarctica) were breeding on the island in December 2012 (Lynch et al. 2013). Antarctic Terns (Sterna vittata) nest in rocky outcrops and 125 breeding pairs were recorded in 1995/96, along with 39 pairs of Kelp Gull (Larus dominicanus) (Garcia Esponda et al. 2000). Wilson's Storm-petrel (Oceanites oceanicus) also breed, with 377 pairs in 1995/96. Other birds breeding in low numbers include the Imperial Shag (Phalacrocorax [atriceps] bransfieldensis), Snowy Sheathbill (Chionis albus), Cape Petrel (Daption capense), Brown Skua (Catharacta antarctica) and Black-bellied Storm-petrel (Fregetta tropica) (Garcia Esponda et al. 2000).
Non-bird biodiversity: Weddell Seals (Leptonychotes weddellii) and Antarctic Fur Seals (Arctocephalus gazella) are regularly observed at local beaches (ATS Visitor Site Guidelines Half Moon Island; Naveen & Lynch 2011).
BirdLife International (2023) Important Bird Area factsheet: Half Moon Island. Downloaded from http://datazone.birdlife.org/site/factsheet/half-moon-island-iba-antarctica on 04/12/2023.