Beaufort Island is located in the southern Ross Sea, ~22 km north of Ross Island, and is ~6 km long and ~2.8 km wide. The island is covered by a permanent ice field on the western and northwestern slopes, with ice cliffs of up to ~20 m lining the northwestern coast. The steep eastern and southern slopes are mostly ice free.
Beaufort Island is of volcanic origin and is part of an extinct caldera that extends to the east as a group of submerged peaks. The formation creates a natural barrier for pack ice and grounding icebergs, which favours winter fast ice development that is important to the viability of the resident Emperor Penguin (Aptenodytes forsteri) colony.
A broad, flat depositional feature in the southwest, called Cadwalader Beach, provides an extensive area of habitat suitable for the large breeding colony of Adélie Penguins (Pygoscelis adeliae). The IBA qualifies on the basis of the Adélie Penguin colony and the boundary is coincident with that of ASPA No. 105: Beaufort Island.
The nearest scientific stations are Scott Base (NZL) and McMurdo (USA), located ~100 km to the south on Hut Point Peninsula, Ross Island.
The main Adélie Penguin colony is located at Cadwalader Beach, and comprised an average of 39 391 breeding pairs from 1981-2012 (Lyver et al. 2014). A smaller sub-colony of a few breeding pairs was first observed on the northern coast in 1995 (C. Harris pers. comm. 2014), and by 2008/09 this had grown to 677 breeding pairs (ASPA No. 105 Management Plan 2010).
An Emperor Penguin colony breeds on fast ice that forms in winter near the northeastern coast of the island. The population ranged from ~100 – ~2000 pairs in the period 1983 – 2005 (Barber-Meyer et al . 2008). Analysis of a satellite image acquired 12 Oct 2009 (Fretwell et al. 2012) indicated that approximately 1641 Emperor Penguins were present, although image quality was rated as Poor.
South Polar Skuas ( Catharacta maccormicki ) nest below cliffs that rise behind the Adélie Penguin colony at Cadwalader Beach. Approximately 150 pairs of South Polar Skuas were estimated breeding at this locality, with a further 50 pairs breeding on the northern coast (ASPA No. 105 Management Plan 2010). Snow Petrels ( Pagodroma nivea ) are confirmed to nest in cliffs along the southern coast of the island (ASPA No. 105 Management Plan 2010).
Non-bird biodiversity: Weddell Seals (Leptonychotes weddellii) have been observed on fast ice near the coast. Leopard Seals (Hydrurga leptonyx), Killer Whales (Orcinus orca), Minke Whales (Balaenoptera acutorostrata) and Arnoux's Beaked Whales (Berardius arnuxii) occur in the vicinity (ASPA No. 105 Management Plan 2010).
BirdLife International (2020) Important Bird Areas factsheet: Beaufort Island. Downloaded from http://www.birdlife.org on 03/12/2020.