This site covers several islands of varying size, located a short distance off the north-western coast of Grande Terre. The main islands of Croÿ, Roland and Ternay form the Îles Nuageuses, while the small Île Clugny is located a little to the south. The coastlines of the islands are mostly sheer cliffs. The islands are free of any introduced species and thus covered in typical subantarctic vegetation, dense up to about 200 m. The site is only rarely visited by man.
See Box for key species. At least 25 species breed. Inventories of the site are only partial; whereas Île de Croÿ has been studied in great detail, no information is available for Île Clugny, apart from observations made at sea. The following figures are therefore underestimates. This site is of major importance both for penguins, and for albatrosses with, in 1989, five pairs of Diomedea exulans, 1,815 pairs of D. melanophris, 7,860 pairs of D. chrysostoma (98% of the population on Kerguelen and 10% of the world’s population) and the only colony of D. chlororhynchos in the archipelago (50 pairs), as well as some 20 pairs of Macronectes halli. Phalacrocorax verrucosus, Anas eatoni, and Sterna virgata all occur in, it is thought, small numbers. It is possible that numbers of breeding Phoebetria palpebrata, Pterodroma brevirostris, Pachyptila desolata, Procellaria aequinoctialis, Oceanites oceanicus, Pelecanoides urinatrix and Chionis minor exceed thresholds for the A4ii criterion, but quantitative data are lacking.
Non-bird biodiversity: The flora is believed to be perfectly preserved. There is a large breeding colony of the fur seal Arctocephalus gazella (over 5,000 females). This population has probably never been exploited, which has enabled the recolonization of other sites from where it has been exterminated.
BirdLife International (2018) Important Bird Areas factsheet: Îles Nuageuses and Île Clugny. Downloaded from http://www.birdlife.org on 15/12/2018.