Island restoration: Saving native species one island at a time

Joker, a trained rabbit-detection dog on Macquarie Island during the programme to remove all invasive mammals, becomes a point of interest for a passing King Penguin. Photo/Karen Andrews

The speaker for next week’s Nature Talks is Keith Springer, operations manager for the Mouse-Free Marion Island Project, BirdLife South Africa.

His talk, titled Island restoration: Saving native species one island at a time, will be given on Tuesday, September 3, 7.30pm, in the Davis Lecture Theatre, Whanganui Regional Museum. Entry is free.

Seabirds are among the most threatened groups of birds globally. They face numerous threats from, among others, unnatural mortality through interactions with fisheries, both as bycatch and from declining fish stocks, compounded by rising sea-surface temperatures and climate change globally; plastic and oil pollution; disease; and, on land, predation by introduced mammals, in particular cats, rats and mice.

For nearly three decades, Keith has been working to eradicate non-native mammals on islands with large and vulnerable seabird colonies. He and his colleagues have developed and refined the means of doing so efficiently and cost-effectively on islands as diverse as Macquarie, South Georgia, Gough, Antipodes and Lord Howe.

In his current position as operations manager for the Mouse-Free Marion Project (https://mousefreemarion.org/) he is primarily responsible for developing, updating and implementing the project’s operational plan to eradicate mice from Marion Island, in South Africa’s sub-Antarctic Prince Edward Islands territory. This project, initiated by BirdLife South Africa and the South African Department of Forestry, Fisheries and the Environment, arose because of rising concerns over many years of the adverse effects that mice are having on nesting seabirds.

Five domestic cats were introduced to the island in 1948 in a misplaced attempt to control the mouse population at the small meteorological station on the island, but the cats spread and became feral, feeding primarily on seabirds, and not controlling mouse numbers at all. By the mid-1970s, cats were estimated to be killing just under half a million seabirds annually. Cats were eradicated by 1991, after a 19-year-long campaign to remove them.

As the recorded climate on Marion Island changed in recent decades, becoming warmer and drier, mouse populations have expanded, as conditions favoured their breeding capacity. Higher summer densities of mice have driven populations of their invertebrate prey to very low levels. Mice now pose an extremely serious threat to nesting seabirds, even attacking birds as large as albatrosses. Left unchecked, mice could cause the local extinction of up to two-thirds of the 28 species of seabirds breeding on the island, some within the next 30 years.

It is in this context that the Mouse-Free Marion Island Project has arisen. Keith, with his wide experience of working on eradicating invasive mammals from sub-Antarctic islands, was appointed operations manager for the project in mid-2021. In this talk, Keith will draw on these experiences to illustrate what can be achieved when invasive predators are removed. His talk is particularly relevant to the Department of Conservation’s Conservation Week (September 2-8) with its theme of Take Action for Nature.

■ Nature Talks is a series of bi-monthly talks offered by three local environmental groups - the Wanganui Botanical Group, the Whanganui branch of Forest & Bird and Birds New Zealand (Whanganui Region) - in conjunction with the Whanganui Regional Museum. The talks are normally given on the third Tuesday, of every second month, on topics that relate to New Zealand’s environment, natural history, and its conservation. For more information contact Peter Frost birds.wanganui@xtra.co.nz.