 They were only briefly stocked with cattle in the 1960s and have good tussac coverage.The Passage Islands group has been identified by BirdLife International as an Important Bird Area (IBA).Birds for which the site is of conservation significance include Falkland steamer ducks, gentoo penguins (300 breeding pairs), southern rockhopper penguins (145 pairs), southern giant petrels, striated caracaras, white-bridled finches, blackish cinclodes and Cobb's wrens.