Kidney Island is roughly kidney-shaped, as its name suggests, and lies about 0.3 miles (0.5 km) off the coast of East Falkland, at the southern entrance to Berkeley Sound. It is largely low lying, with the highest point at 18 m above sea level, and is almost covered with mature Tussac. There are boulder beaches on eastern and western coasts, a large sand bay facing south-west and near-vertical cliffs along much of the northern coastline. Cochon Island is a small island lying adjacent to Kidney Island, formed from steeply dipping rocks, which rise to over 30 m at the island’s highest point. The soil is generally thin and vegetation is limited to Tussac, Wild Celery and Stonecrop, which vary in density throughout the rocky ridges.
At least 34 species have been recorded breeding on Kidney Island since 1960. The most numerous is the Sooty Shearwater, which was apparently confined to the western headland and steep north-western slopes in the 1930s, but now burrows around the coast and well inland. Kidney Island has one of only three known Falkland breeding colonies of White-chinned Petrels. It is also the only definite breeding site for Great Shearwaters outside the Tristan da Cunha and Gough Island group in the South Atlantic. Grey-backed Storm-petrels breed, but are very difficult to count. Common Diving Petrels traditionally bred but have not been found nesting in recent years. One or two pairs of Macaroni Penguins breed regularly with the Rockhoppers on Kidney, and small numbers of Rock Shags and Imperial Shags are present, but populations have not been counted recently. Canary-winged/Black-throated Finches formerly bred on Kidney but are now rarely seen, and one or two pairs of Ruddy-headed Geese have bred there since 1983. These small numbers, however, do not qualify the site. Other endemic sub-species recorded are the Black-crowned Night-heron, Upland Goose, Short-eared Owl, Dark-faced Ground-tyrant, Falkland Pipit, Falkland Grass Wren, Falkland Thrush and the Long-tailed Meadowlark.
Non-bird biodiversity: Both islands are used by Southern Sea Lions for hauling out, and they can often be found resting in Tussac, sometimes well inland and at the top of long slopes, but apparently they do not now breed there. At least 26 species of flowering plants have been recorded in recent years on Kidney Island, including the two endemic ragworts, Woolly Falkland Ragwort Senecio littoralis and Smooth Falkland Ragwort Senecio vaginatus. The Swordgrass (sedge) Carex trifida grows well with shorter Tussac. Preliminary collections and surveys of the invertebrate fauna and flora have been made because Kidney is an accessible, mature Tussac island.
BirdLife International (2021) Important Bird Areas factsheet: Kidney Island Group. Downloaded from http://www.birdlife.org on 13/04/2021.