Part of the UK Overseas Territory of Tristan da Cunha, Gough Island is home to more than eight million breeding birds from at least 24 different species, including highly threatened species such as the Endangered Atlantic yellow-nosed albatross, Atlantic petrel and MacGillivray’s prion, and the Critically Endangered Gough bunting and Tristan albatross.
Mice were accidentally introduced by sailors to the remote Gough Island during the 19th century. These rodents colonised this World Heritage Site and learnt to exploit all available food sources on the island – including seabirds. Video cameras reveal how the mice eat the flesh of live seabird chicks – and, more recently, live adult birds too. Tristan albatross chicks weigh up to 10kg but the open wounds inflicted by the mice – who are a fraction of their size – frequently lead to chick deaths.
The situation was so severe that just 21% of Tristan albatross chicks survived to fledge during the 2017/18 breeding season. And for endangered burrow-nesting species breeding success has been recorded as low as 0%.
The RSPB and Tristan da Cunha developed an ambitious programme to save the Tristan albatross and other highly threatened species on Gough, such as MacGillivray’s prion and Atlantic petrel by removing the island’s mouse population. We attempted this in 2021 but, sadly, in early 2022 we learned that mice were still present on the island.
We know that the restoration attempt will provide a window of opportunity for Gough’s birds and some respite from heavy mouse predation pressure. With a breeding success of 63%, Atlantic petrels appear to have raised more than twice as many chicks in 2021 as in previous years in the near-absence of mice.
The RSPB remains resolute in its commitment to see Gough Island restored but it will be vital to understand why this first attempt was unsuccessful before any other attempt at removing the mice is made. This is likely to take some time.