Kath Walker talks about her experiences on the subantarctic islands…
“Antipodes Islands free of mice – what a dream! On mouse-free Adams Island in the subantarctic Auckland Island group, the snipe are so abundant you hear them all the time and literally trip over them. Once on Adams Island as I trudged back to camp carrying a butterfly net by my side, I accidentally scooped a snipe up in it; they are that common. In stark contrast, on Antipodes Island where mice are abundant, 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 which cover the whole island have seeded, the mouse numbers explode. They are everywhere. Even the rain gauge fills daily with drowned mice. The high numbers of 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.
Graeme Elliott and I have spent a lot of time on both Adams and Antipodes Islands studying the wandering albatrosses there. To us, the contrast between the former mouse-free and latter mouse-full island seems stark. The video of mice on Gough Island in the south Atlantic Ocean, growing large enough to eat alive the wandering albatross chicks there, show a future I hope never comes to Antipodes Island. Its incredibly exciting, but also nerve wracking, to be so near to reaching that long-held dream of a mouse-free Antipodes Island.”