By Kath Walker, Science Advisor in Nelson.
Mice were introduced to the Antipodes Islands probably by accident from a shipwreck in 1893. They are the only mammal pest on the islands, predating birds, invertebrates and plants.
For Antipodes Island’s native species to thrive, the mice must go.
A stark contrast
On mouse-free Adams Island in the subantarctic Auckland Island group, snipe are so abundant you hear them all the time and literally trip over them. They are so common that once as I trudged back to camp carrying a butterfly net by my side I accidentally scooped a snipe up in it!
In stark contrast, mice are abundant on Antipodes Island and the endemic snipe are rare and quiet. Snipe eat insects and unfortunately mice do too. Lots of them.
By late summer on Antipodes, when the grasses covering the island have seeded, the mouse numbers explode. They are everywhere. Even the rain gauge fills daily with drowned mice.
The mice have decimated the insect populations on Antipodes. Unlike Adams Island where you see large leaf vein slugs, weevils and beetles on every giant megaherb, charismatic invertebrates on Antipodes Island seem to be simply… missing. By removing so much of the invertebrate biomass, mice must indirectly be having a big impact on the number of snipe the island can support.
DOC scientist Graeme Elliott and I have spent a lot of time on both Adams and Antipodes islands studying wandering albatrosses. To us, the contrast between the mouse-free and mouse-full islands is dramatic.
This video shows mice on Gough Island (in the south Atlantic Ocean) that are large enough to eat alive albatross chicks – a future I hope never comes to Antipodes Island.
It’s incredibly exciting, but also nerve-racking, to be so near to reaching that long-held dream of a mouse-free Antipodes Island.
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