Bird Island is located 3 miles (4.5 km) off the south-western coast of West Falkland and is roughly triangular in shape. The western half of the southern coast has sheer cliffs reaching at least 70 m and the plateau above slopes gently to the north and west. In the centre of the island there is a large seasonal pool, to the west of a small inlet. The eastern promontory has two domed peaks reaching to at least 110 m with sheer southern cliffs of 30 m and very steep slopes in the north. Access by boat is difficult, except at the small north-east-facing inlet between the northern and eastern promontories, and the terrain is difficult to cross, with dense growth of Tussac above thick, soft peat and Tussac overhanging deep gulches.
The total number of species recorded on Bird Island in November 1998 was 27, of which 25 bred or were probably breeding. Macaroni Penguins, Ruddy-headed Geese, Canary-winged/Black-throated Finches and Falkland Steamer Ducks are present but their status is uncertain or populations are too small to qualify. The congregation of seabirds on this island exceeds 10,000 breeding pairs, making the site classifiable under the A4iii criterion. Bird Island is one of the most important breeding sites for the Striated Caracara and it is considered that the population here is at least as dense as on any offshore island around the Falklands, possibly due to the very large population of Thin-billed Prions, an important prey species. Deep Tussac cover over most of Bird Island makes it comparable to Beauchêne Island for the density of burrowing petrels. Other species that should be investigated include the Sooty Shearwater, Grey-backed Storm-petrel, which is thought to be numerous, Rock Shag, Imperial Shag and the Dolphin Gull. Endemic races present include the Dark-faced Ground-tyrant, Falkland Thrush, Long-tailed Meadowlark and the Common Diving-petrel.
Non-bird biodiversity: There are two colonies of South American Fur Seals present on Bird Island, one of about 100 individuals on the northern coast, the second on the south-western coast, comprising approximately 10,000 individuals: the largest South American Fur Seal colony within the Falklands archipelago. The island also provides a haul-out for Southern Sea Lions, although they are not known to breed there. No endemic or introduced species were recorded in 1998; only 12 native flowering plants were found with Tussac predominant.
BirdLife International (2019) Important Bird Areas factsheet: Bird Island. Downloaded from http://www.birdlife.org on 06/12/2019.