The Critically Endangered Tristan Albatross Diomedea dabbenena, has suffered its worst breeding season ever, according to research by the RSPB (BirdLife in the UK). The number of chicks making it through to fledging has decreased rapidly and it is now five times lower than it should be because introduced predatory mice are eating the chicks alive on Gough island - the bird’s only home and a South Atlantic territory of the United Kingdom.
The mice are also affecting Gough Island’s other Critically Endangered endemic species, Gough Bunting Rowettia goughensis. A recent survey of the bunting’s population revealed that the population has halved within the last two decades. Now there are only an estimated 400-500 pairs left.
“We’ve known for a long time that the mice were killing albatross chicks in huge numbers. However, we now know that the albatrosses have suffered their worst year on record”, said Richard Cuthbert, an RSPB scientist who has been researching the mice problem on Gough Island since 2000. “We also know that the mice are predators on the eggs and chicks of the Gough bunting and mice predation is the main factor behind their recent decline.”
Despite the grave situation for both species on Gough Island, UK government funding to plan for and take forward the eradication of mice is still lacking. This is despite recognition from two prominent UK House of Common's Committees that the "biodiversity found in the UK Overseas Territories is equally valuable and at a greater risk of loss" (than the UK) and that current levels of funding are "grossly inadequate". Eradicating mice is the single action that would solve the primary conservation threat facing both species.
A complete survey of the Tristan Albatross on Gough Island in January showed there were 1764 adult albatrosses incubating eggs. A later survey revealed that only 246 chicks had survived to fledging.
“Tristan Albatross is being hit by a double whammy. The chicks are predated by mice and the adults and juveniles are being killed by longline fishing vessels”, said John Croxall, Chair of BirdLife’s Global Seabird Programme. “Unsustainable numbers are being killed on land and at sea. Without major conservation efforts, the Tristan Albatross will become extinct”.
The RSPB has been involved in a feasibility study to test whether it’s possible to remove the mice. So far, the trials look promising, giving both species a more optimistic future. Funding of this year's work on Gough has come from the Overseas Territory Environment Programme (OTEP).
“Tackling alien invasives species in UK Overseas Territories is one of 10 Key Actions to prevent extinctions that BirdLife has highlighted in a new publication, Critically Endangered Birds: a global audit”, said Richard Grimmett, BirdLife’s Head of Conservation. “It is also attainable, the removal of rats from seabird islands has been conducted at many other sites across the world with great success.”
Alistair Gammell, the RSPB’s International Director continued “It is essential that the UK Government commits adequate funding for the protection of the many threatened species found on the UK’s Overseas Territories. We are challenging the Government to prove its commitment to conservation by properly funding conservation initiatives in these territories, and most urgently to commit to funding the removal of mice from Gough.”