Endangered seabirds including MacGillivray’s Prion, are inching closer to extinction on Gough Island, and removing invasive mice will be a saving grace for these birds.

Gough Island in the South Atlantic is a UNESCO World Heritage Site home to around 8 million seabirds including the Tristan albatross (Diomedea dabbenena), Atlantic Petrel (Pterodroma incerta), and Atlantic yellow-nosed Albatross (Thalassarche chlororhynchos).

Accidentally introduced to the island in the 19^th century, invasive mice have flourished on Gough, adapting to feed on eggs and seabird chicks. Two species, in particular, the MacGillivray Prion (Pachyptila macgillivrayi) and Tristan Albatross are highly endangered due to high rates of breeding failure resulting from predation by mice. Researchers have also observed mice attacking adult seabirds, often leaving fatal wounds.

The Royal Society for the Protection of Birds, or RSPB, and Tristan da Cunha in partnership with the UK Government, Island Conservation, and others plan to restore the Gough’s ecosystem by removing invasive mice.

MacGillivray’s Prions typically breed in Prion Cave on Gough Island from November through April. In 2014, RSPB began monitoring the Prions breeding site, using survival rate as an indicator of how well the birds were doing on Gough Island. Since then, only 21 chicks out of around 370 monitored nests have successfully fledged or taken flight. During the 2021 breeding season, only one chick survived, reinforcing fears that the MacGillivray’s Prions may be edging closer to extinction. Unless the mice are removed, extinction is almost certain.

Recently, a paper published in the journal Animal Conservation, predicts that the birds will continue to decline by 9 percent each year if mice remain on Gough, with a 31% chance they will go extinct by 2057. However, there is hope that the population will be able to stabilize and recover if mice are successfully removed.

The project to begin the restoration process, originally set to begin in 2020 was delayed due to the coronavirus until summer 2021. Kim Stevens, RSPB’s Senior Field Assistant is looking forward to a mouse-free Gough Island, saying:

With the restoration project so close at hand, I have every hope that we will soon be able to make the island a global haven for seabirds once more.”

Feature Photo: A MacGillivray’s Prion chick. Credit: RSPB