Alone in the Atlantic: at least one pair of Tristan Albatrosses continues to breed on mouse-free Inaccessible Island

 The Critically Endangered Tristan Albatross Diomedea dabbenena breeds only on Gough and Inaccessible islands in the United Kingdom’s Tristan da Cunha group, with the population on the main island of Tristan long extinct.

The bulk of the species’ population breeds on Gough, where many of the downy chicks die every winter following attacks by introduced House Mice Mus musculus - as has been regularly reported in ACAP Latest News (click here to read of this year’s very poor breeding season on Gough).

In recent years the population on mouse-free Inaccessible has varied from none to one pairs attempting breeding annually – way down from an estimate of some 200 pairs in the 1870s.  It is considered that no more than three pairs now breed on the island, given that the species is normally a biennial breeder when successful.  This will make it the smallest island population of any great albatross.  The next smallest population is thought to be the seven pairs of Wandering Albatrosses D. exulans that are breeding on Australia's Macquarie Island this year (click here).

The last recorded breeding attempt by a Tristan Albatross on Inaccessible Island was in 2012 when an incubating bird was photographed in March on the island’s plateau (click here).  No further visits were made that year so the outcome of the breeding attempt is not known.  It seems the plateau was not visited during the course of 2013.

Bruce Dyer (South African Department of Environmental Affairs) along with island guides Riaan Repetto and Damian Swain from the Tristan Conservation Department visited Inaccessible last month, when a single Tristan Albatross chick was located and photographed on Gony Ridge on the island's plateau on the 17th.  The large downy chick had commenced feathering and in the absence of rodents on the island it is thought likely it will fledge around year end.  No adults were present during the visit.

The 2104 Tristan Albatross chick on Inaccessible (with Tristan in the background)

Photograph by Bruce Dyer

Click here to read of breeding by a single pair of Tristan Albatrosses on Inaccessible Island in 2011.

The 2011 chick on Inaccessible, photograph by Peter Ryan

With thanks to Bruce Dyer and Peter Ryan for information and photographs.

John Cooper, ACAP Information Officer, 16 October 2014