|Central coordinates||45o 37.68' West 60o 42.59' South|
|IBA criteria||A4i, A4ii, A4iii|
|Altitude||0 - 278m|
|Year of IBA assessment||2011|
Site description Signy Island lies 1.6 km southwest of Cape Hansen on the south coast of Coronation Island. The IBA comprises all of Signy Island and several offshore islands including Confusion Island, Oliphant Islands, Spindrift Rocks and Shagnasty Island.
Almost half of Signy Island is covered by a permanent ice cap, with the highest point on the island being Tioga Hill (278 m). The coastline is dominated by exposed crags,and rocky headlands, with intervening bouldery slopes and sizeable moss banks (Tickell 1962). There are 16 lakes on the island and several glaciers, the largest of which is McLeod Glacier which terminates on the southern coast.
Extensive Chorisodontium – Polytrichum moss turfs occur particularly on the northwest coast of Signy Island, forming primary breeding habitat for burrowing petrels (R. Fijn, pers. comm. 2011). Other flora on Signy Island includes the Antarctic hairgrass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus quitensis), ~50 moss species, ~12 liverworts and ~120 lichen species (BAS, Signy Island Research Station, accessed 02/09/2010). Algae and cyanobacteria have also been observed in wetter sites on the island (Broady 1979).
Signy Research Station (UK) is located midway along the eastern shoreline of Signy Island, on the southern side of Borge Bay. The facility supports mainly biological research, including for long-term ecosystem monitoring and climate studies. The station accommodates ~8 people (COMNAP, Antarctic Facilities, accessed 31/08/2010).
The winter climate on Signy Island is influenced by pack ice which extends to surround the island from the Weddell Sea. Over the summer the pack ice retreats and Signy Island has a typically maritime climate. Mean summer air temperatures are between –2°C to 3°C, whilst during winter the mean monthy air temperature ranges from –2°C to –17° C (ASPA No. 114 Management Plan, 2003). Meteorological records for Signy Station show strong winds are frequent, prevailing from the west (BAS, Signy Island Research Station, accessed: 02/09/2010). The minimum winter temperature on record is –39.3°C whilst in summer, temperatures range from – 7°C to 19.8°C.
Key Biodiversity An exceptionally diverse range of seabirds and waterbirds breed on Signy Island, including three species of penguin, four petrel species, two storm petrel species, shags, sheathbills, two species of skua, gulls and terns.
Approximately 19,530 breeding pairs of Chinstrap Penguins (Pygoscelis antarctica) breed on Signy Island (BAS unpublished data, 2010), with the most concentrated breeding sites on Gourlay Peninsula, an ice-free gently sloping peninsula on the southeast side of Signy Island; Pandomonium Point, on the southwest coast of Signy Island; Confusion Island, 100 m off the south of the island; and North Point (Croxall & Kirkwood 1979). This recent count is likely to be an under-estimate of typical Chinstrap breeding numbers, since this season was reportedly a poor one for this species (M. Dunn, pers. comm. 2011). Approximately 16,900 pairs of Adélie Penguins (Pygoscelis adeliae) also breed at Gourlay Peninsula and North Point (Dunn et al. 2010), and 753 pairs of Gentoo Penguin were recorded breeding for all Signy Island in 2010 (BAS unpublished data, 2010). Macaroni Penguins have not been recorded breeding on Signy Island or its offshore islands for many years, and were last observed breeding in low numbers (11 pairs) in 1979 (Woehler 1993).
Imperial Shags (Phalacrocorax atriceps) breed on ledges of low cliffs on the north coast of Signy Island and constituted 280 pairs in 2006-07 (R. Fijn pers. comm. 2011). Three larger groups of Imperial Shag may breed on flat or shallow-sloping areas on two islets near Shagnasty Island, as Rootes (1988) reported a total of 729 pairs in this area in the mid 1980s, although more recent data on these colonies is not available.
The latest survey in 2005-06 revealed 2351 pairs of Southern Giant Petrel (Macronectes giganteusi) breeding on Signy Island, predominantly on the western coast. Approximately 1093 breeding pairs were recorded at North Point, G.P. Ridge and Borge Bay in 1984 (Patterson et al. 2008).
High numbers of Wilson’s Storm-petrel (Oceanites oceanicus) breed on Signy Island in crevices and between boulders in ice-free areas, and it has been estimated that up to 200,000 breeding pairs were present on the island in 1966-68 (Beck & Brown 1972). It was also estimated that approximately 50,000 pairs of Antarctic Prion (Pachyptila desolata) breed on Signy Island, concentrated at Borge Bay on the eastern coastline close to Signy Station (Tickell 1962). However, accurate counts of these species are difficult and numbers are approximate.
Approximately 100 pairs of Brown Skua (Catharacta lonnbergi) and a small number of South Polar Skua (Catharacta maccormicki) breed on Signy Island (Ritz et al. 2005). In addition, 195 pairs of Snow Petrel (Pagodroma nivea) were recorded breeding on Signy Island in 1985 (Croxall et al. 1995).Other birds breeding on Signy Island include the Cape Petrel (Daption capense), Greater Sheathbill (Chionis alba), Kelp Gull (Larus dominicanus), Antarctic Tern (Sterna vittata) and Black-bellied Storm-petrel (Fregetta tropica) (BAS: Signy Island Research Station, 2010).
Non-bird biodiversity: Antarctic Fur Seals (Arctocephalus gazella) haul out in large groups around the coast of Signy Island, concentrated on the eastern and southern coastline, with an estimated 12,245 individuals present in February 2009 (BAS unpublished data, 2009), although numbers vary and reached over 21,000 individuals in 1994 (Waluda et al. 2009). Weddell Seals breed on the sea-ice around Signy Island over the winter months, and Southern Elephant Seals (Mirounga leonina) have been observed pupping in spring (BAS, Signy Island Research Station, accessed 22/09/2010). In 2009, 309 Southern Elephant Seals and 5 Weddell Seals (Leptonychotes weddellii) were observed hauled out on Signy Island (BAS unpublished data, 2010).
|Species||Season||Period||Population estimate||Quality of estimate||IBA Criteria||IUCN Category|
|Southern Giant Petrel Macronectes giganteus||breeding||2005-2006||2,351 breeding pairs||-||A4ii||Least Concern|
|Phalacrocorax atriceps||breeding||1988||801 breeding pairs||-||A4i||Not Recognised|
|Catharacta lonnbergi||breeding||2003-2005||100 breeding pairs||-||A4ii||Not Recognised|
|A4iii Species group - seabirds||breeding||1968-2006||207,152 breeding pairs||-||A4iii|
|Wilson's Storm-petrel Oceanites oceanicus||breeding||1968||200,000 breeding pairs||-||A4ii||Least Concern|
Protection status None
References British Antarctic Survey, Signy Island Research Station. URL:http://www.Antarctica.ac.uk/living_and_working/research_stations/signy/. Accessed: 02/09/2010.
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Recommended citation BirdLife International (2015) Important Bird and Biodiversity Area factsheet: Signy Island. Downloaded from http://www.birdlife.org on 29/11/2015
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