The Ascension Frigatebird Fregata aquila is the only extant endemic bird on Ascension. Its population currently numbers some 6,000 individuals and the species is classed as "vulnerable" (BirdLife International 2000). Breeding is restricted to the summit of predator-free Boatswainbird Island, but it is hoped that, with the removal of feral cats, frigatebirds will recolonise their old nesting areas on the main island. The majority of the population appears to remain within Ascension waters outside the breeding season but some have been known to wander to the West African coast and there is even a record from the British Isles!
Ascension contains two Important Bird Areas (IBAs) Ascension island: mainland and stacks and Boatswainbird Island - see reference (Rowlands 2001). The mainland and minor stacks include the major Sooty Tern Sterna fuscata colonies south of the airfield and cliff sites for nesting seabirds, particularly Red-billed Phaethon aethereus and White-tailed Tropicbirds P. lepturus, Black Noddies Anous minutus and Fairy Terns Gygis alba. The most important cliff colonies are located along the south-eastern coast and around Letterbox and Cocoanut Bay. Offshore stacks support a population of around 500 pairs of Brown Noddies Anous stolidus. The mainland IBA also covers several former seabird nesting sites on the lava plains, which may be re-occupied in the absence of cats.
The current major seabird colony is Boatswainbird Island. In addition to being the only breeding site for the Ascension Frigatebird Fregata aquila, the island supports a small (around ten pairs in recent times) population of Red-footed Boobies Sula sula. Eight of Ascension’s other nine seabird species also nest on Boatswainbird Island, the exception being Brown Noddy Anous stolidus. Boatswainbird holds the majority of Ascension’s Madeiran Storm-petrel Oceanodroma castro population.
Ascension Island is listed as a secondary Endemic Bird Area as it falls short of the minimum criterion of two endemic species for full citation.
For further details, download the country IBAs from BirdLife International.