Amsterdam Albatross (Diomedea amsterdamensis)
Justification This species qualifies as Critical because it has an extremely small population of mature individuals, confined to a tiny area on one island. Although numbers have been recently increasing, a continuing decline is projected owing to the impact of a disease which is probably already causing chick mortality.
Identification 110 cm. Huge albatross breeding in brownish plumage. Juvenile very similar to juvenile Wandering Albatross D. exulans. Adult has almost entirely chocolate-brown upperparts. White face mask and throat. Broad brown breast-band. White lower breast and belly with brown undertail-coverts. White underwing with dark tip. Similar spp. Dark leading edge to underwing possibly broader than in D. exulans. Dark tip and cutting edges to pink bill characteristic, and best identification feature if visible, compared to, for example, Antipodean Albatross D. antipodensis which lacks dark marks on bill.
Population estimate 80
Population trend decreasing
Range estimate 7 km2
Country endemic? yes
Range & Population Diomedea amsterdamensis breeds on the Plateau des Tourbion Amsterdam Island (French Southern Territories) in the southern Indian Ocean. It has a total population of c.130 birds including 80 mature individuals, with c.18-25 pairs breeding annually, showing an increase since 1984, when the first census was carried out The population was probably formerly larger when its range was more extensive over the slopes of the island8. During the breeding season, birds forage both around Amsterdam Island and up to 2,200 km away in subtropical waters, but non-breeding dispersal is unknown, although possible sightings have been reported from Australia and New Zealand.
Ecology Its exact diet is unknown, but probably consists of fish, squid and crustaceans. Breeding is biennial (when successful) and is restricted to the central plateau of the island at 500-600 m, where only one breeding group is known.
Threats Degradation of breeding sites by introduced cattle has decreased the species's range and population across the island. Human disturbance is presumably also to blame. Introduced predators are a major threat, particularly feral cats. Interactions with longline fisheries around the island, in the 1970s and early 1980s, could also have contributed to a decline in the population. Today the population is threatened primarly by the potential spread of diseases (Avian cholera and Erysipelothrix rhusiopathidae) that affect the Indian Yellow-nosed Albatross Thalassarche carteri population 3 km from the colony. Infection risks are very high and increased chick mortality over recent years suggest that the population is already affected.
Action All birds are banded and the population is censused and monitored every year. In 1987, the number of cattle was reduced and a fence erected to seal off part of the island. In 1992, a second fence was erected with the aim of providing complete protection for the high plateau from possible incursions by cattle.
