Mouse-Free Marion - a project that will save seabirds by eradicating Albatross-killing mice from this globally important Sub-Antarctic Island.

Aiming High: in 2024 South Africa will commence Operation Mouse-Free Marion to eradicate Albatross-killing mice on Marion Island. Located in the Southern Ocean, this will be the largest seabird island on which this has ever attempted.

In an ambitious undertaking, the Mouse-Free Marion Project aims to remove introduced House Mice which are endangering the long-term survival of seabirds and other native species on South Africa’s sub-Antarctic Marion Island. Thought to have been accidentally brought to Marion by sealers in the early 19th century, the mice have had a devastating impact on the ecology of the island by attacking and literally eating alive the chicks - and even adults - of both surface-nesting and burrowing seabirds.

***The Mouse-Free Marion Project aims for a better future for this Wandering Albatross chick on Marion Island. Photograph ©Sean Evans***

Birds on the Brink co-Founder and Trustee, Andrew Cleave MBE commented: ‘At Birds on the Brink we are all-too aware of the havoc wreaked when terrestrial mammals are introduced to seabird islands that should otherwise be free of terrestrial mammals. We have seen first hand the impact all around the globe, including on Bermuda, where cats and rats were among the factors that brought the Cahow (Bermuda Petrel) perilously close to the brink of extinction; and New Zealand’s Chatham Islands where Chatham and Magenta Petrels narrowly escaped extinction at the jaws of mammalian threats ranging from cats, rat species, pigs and Possums. Closer to home, there’s the UK island of Lundy from which two species of rat have been eradicated, and seabird numbers have rebounded almost exponentially. Marion Island is on a much grander scale, and is one of the most important seabird islands on the planet. But what projects large and small have in common is a committed band of dedicated enthusiasts and a need for funding. Birds on the Brink is thrilled to help with a donation. In the grand scheme of things our contribution may just be a drop in the ocean, but in financial terms every little helps. And we hope that by spreading the message others will dig into their pockets and help too. We wish the Mouse-Free Marion Project every success.’

***These Grey-headed Albatross chicks will not survive their gruesome overnight ‘scalping’ by Marion Island’s House Mice. Photograph ©Ben Dilley***

Marion Island is home to globally important populations of seabirds, including a quarter of the world’s entire population of Wandering Albatrosses, an iconic species both famous in rhyme and for having the largest wingspan of any living bird. Three other albatross species breed on the island, along with many species of burrowing petrels, some still in huge numbers, as well as four species of penguins.

***A Wandering Albatross displays its impressive three-metre wingspan on Marion Island. Photograph ©John Dickens***

Without immediate action, Marion Island’s seabirds face local extinction. Left unchecked, the mice are predicted to cause the disappearance of 18 of the 28 species of breeding seabirds currently found on the island.

***A House Mouse feeds on the exposed head of a living Wandering Albatross chick at night. The birds have evolved no protection against this alien invader. Photograph ©Stefan Schoombie***

Ongoing warming due to climate change is providing more favourable conditions for mice and intensifying their impacts on Marion’s seabirds. Removing the mice will help secure the ecological integrity of this important sub-Antarctic island and a favourable future for its globally important seabirds. The project will also build capacity within South Africa’s conservation community for ongoing restoration efforts.

***A satellite view of Marion Island on a rare cloudless day in the Southern Ocean: with the mice eradicated, its ecology and its native inhabitants will start to recover.***

In the southern hemisphere winter of 2024 helicopters brought by sea across the ‘Roaring Forties’ from South Africa will spread rodenticide bait from underslung bait buckets in overlapping swathes across the entire island - this is the only method that has so far proven successful in eradicating rodents from large islands. At 30, 000 hectares, Marion will be substantially larger than all previous rodent eradication efforts undertaken on islands in a single operation.