Bird Island is a sandy cay rising only a few metres high, situated on the northern edge of Seychelles Bank about c.100 km north-west of Mahé. It is very young, perhaps having emerged no more than 4,000 years ago. The island was sparsely vegetated and supported large numbers of seabirds until the end of the nineteenth century. Coconut-palms Cocos nucifera were then planted over most of the island, but were partly cleared after 1967 to encourage the breeding of Sterna fuscata. About 70% of the island is now covered with mixed woodland. This includes the remaining coconut plantation, areas planted with Casuarina equisetifolia and Pisonia grandis forest that has been allowed to regenerate in the centre of the island. Main human activities are tourism (there is a small hotel served by plane from Mahé), small-scale fisheries and aquaculture.
See Box for key species. The island supports a huge and increasing breeding colony of Sterna fuscata. More than one million are present during the breeding season between April and October; the species is rare or absent the rest of the year. There is also a large colony of Anous stolidus. Other breeding species include Puffinus pacificus (uncommon), Gygis alba (720 pairs), Anous tenuirostris (300 pairs, increasing) and Phaethon lepturus (10–20 pairs). A population of Streptopelia picturata (30–60 individuals) is also present, with many individuals showing characteristics of rostrata. Non-breeding visitors include more than 250 Sterna saundersi and 5,000 S. anaethetus.
Non-bird biodiversity: The island hosts one species of skink and one species of gecko endemic to Seychelles. Green turtles Chelonia mydas (EN) nest in larger numbers than elsewhere in the granitic islands and hawksbill turtles Eretmochelys imbricata (CR) also breed; numbers of both are monitored. A small number of the giant tortoise Dipsochelys dussumieri have been introduced.
BirdLife International (2019) Important Bird Areas factsheet: Bird Island (Ile aux Vaches). Downloaded from http://www.birdlife.org on 16/10/2019.