The site comprises a section of south east coastline including Gill Point and the offshore islands of George Island and Shore Island. Shore Island is a large, steep basaltic stack; whereas George Island, also basaltic, is shoe-shaped, less steep, its 'toe' pointing into the south-easterly swell. The site habitat comprises of arid volcanic steep high cliffs (rising mainly to between 300 m and 570 m) leading into incised semi-desert habitat (Prater, 2012).
See table for key species. There are 10 breeding species of seabirds in St Helena: Bulweria bulwerii, Pelagodroma marina, Oceanodroma castro, Phaethon aethereus, Sula dactylatra, Sula leucogaster, Onychoprion fuscatus, Anous stolidus, Anous minutes and Gygis alba. St Helena supports the most southerly breeding colonies of Phaethon aethereus in the Atlantic, with this site supporting the second largest breeding colony with 130 adults present in 2014 (George & Beard, 2014). Sula dactylatra were first recorded breeding in the mid 1980s (Rowlands et al., 1998) and c.200 adults were seen around George and Shore Islands in the 1990s with a limited number of breeding pairs. From 2009 a number have bred on the top ridges on the mainland near Lot’s Wife’s Ponds and by 2011 over 150 adults were present with 40 pairs breeding successfully (Bolton et al., 2011; EMD data). A juvenile and adult Bulwer’s petrel Bulweria bulwerii was found dead in a cat lair at Gill Point in 1995 (Ashmole et al., 1995).
Non-bird biodiversity: The seas around St Helena support a small number of Whale Sharks Rhincodon typus from January to May along with resident Pantropical Soptted Dolphins Stenella attenuata and a few bottlenose dolphins Tursiops truncatus (Prater, 2012). Humpback Whales Megaptera novaeangliae calve off the coast from June to December. The waters are regularly used by Hawksbill Eretmochelys imbricata and Green turtles Chelonia mydas.
BirdLife International (2019) Important Bird Areas factsheet: Great Stone Top and Shore Island. Downloaded from http://www.birdlife.org on 22/09/2019.