Île de l’Est is, as its name suggests, the easternmost island of the Crozet archipelago. It is also the most mountainous, reaching 1,090 m, with a coastline of high cliffs. Several steep-sided valleys of glacial origin cut across the island, in three of which rabbits occur, the only introduced animal species. Otherwise, the landscape is mainly mountainous bare rock. There is no human presence or infrastructure on the island, which is only rarely visited by research scientists.
See Box for key species. In addition, numbers of Pterodroma lessonii, Anas eatoni and Chionis minor are believed to exceed thresholds, but no quantitative data are available. This island holds the most diverse community of seabirds in the world: 32 species, of which 19 are hole-nesting petrels. Many are believed to number tens of thousands of pairs. Three taxa are particularly abundant, Pelecanoides georgicus, P. urinatrix and Pachyptila salvini salvini. Estimates of the population sizes of each are of several million pairs which, in the case of P. s. salvini, represents 80% of its global population. The site is also home to 350 pairs of Diomedea melanophris.
Non-bird biodiversity: The island is home to the largest population of the mammal Mirounga leonina in the archipelago. Orcinus orca (LR/cd) occur in coastal waters. There is no information on fur seals Arctocephalus spp. Three endemic plant and 59 endemic arthropod species occur.
BirdLife International (2021) Important Bird Areas factsheet: Île de l'Est. Downloaded from http://www.birdlife.org on 13/04/2021.