By Alison Ballance
Bollons Island is a steep 50-hectare jellybean-shaped island lying off the northern tip of Antipodes Island. It’s believed to be mouse-free, which makes it one of the very few pristine islands in the subantarctic, but mouse eradication manager Steve Horn needs to confirm its status to be sure that it doesn’t need to be treated during the eradication, and that its pipits and parakeets will be a vital insurance population to those on the main island.
Bollons Island is seldom visited, due to both its pristine state, and the difficulty of the landing, but the sea state on Saturday was good enough, and Denise and Brian got ready to go ashore. They had to take some emergency equipment with them, just in case they couldn’t be picked up, along with a day pack each and two sets of long marker poles.
Steve and Hamish were driving the dinghy, and as they motored over to the only landing site on the western side of the island they were faced with a steep bull kelp-covered slope with waves washing 3-metres up it. Brian leapt ashore, and after getting wet legs from a large wave he began to wrangle the awkward fish bin containing some of the emergency gear up the rock face, searching for a safe place to stash it. Denise followed, clutching two dry bags – but a second, even larger, wave swept her off her feet and off the rock, to become the inaugural member of the Antipodes Island swim club. Brian looked behind expecting to have Denise hot on his tail, but glancing down saw several bright shapes in the water, with one of them being Denise in her flouro DoC jacket.
Wearing a lifejacket and holding tightly onto a buoyant dry bag Denise was quickly rescued by the dinghy crew, and as they pulled her aboard she brightly quipped “First swim of the summer!” Her other comment was that the water wasn’t as cold as she had expected.
Denise was whisked back to Evohe, where she changed out of her wet clothes and headed back for a second, more successful (and dry) landing attempt.
Bollons Island is very steep on all sides with a small plateau on the summit, and the route involves climbing up a sharply angled slope, following GPS co-ordinates marked by Hannah and Mitch from the winter expedition. Denise and Brain were pleased that despite the low thick mist the slope was dry, so there was some grip for their boots, and the mist also obscured the very exposed slope below them. With visibility no more than 30 metres, Denise says the experience was very ethereal, especially with pairs of light mantled sooty albatrosses appearing out of the mist on their signature synchronised courtship flights.
They had a number of tasks to complete, including checking tracking tunnels, which contained ink pads and paper that collected footprints from animals such as invertebrates and possibly mice, if there were any. They found 7 of the 8 tunnels, but unfortunately the strong winds that are a feature of subantarctic had had their effect and only 2 still had recognisable papers. They added stakes as markers and an additional set of permanent wooden tracking tunnels that should be more robust.
They found 5 out of 6 weta boxes, but no weta had taken advantage of the free homes. The weta from Bollons Island is known from just one specimen, and scientists need more specimens to confirm whether it’s a new species. As well, large soft-bodied insects such as weta are the first to disappear when rodents invade, so the presence of weta would be another sign that Bollons Island truly is mice free. Brian and Denise also put out some pitfall traps, that are small pottles set in the ground into which wandering invertebrates fall – these collections will be compared to the main island to see how rich the two invertebrate faunas are.
Brian recorded 26 species of plants, including a few of the megaherb Stilbocarpa, and he was struck by the large numbers of the endemic Senecio , especially on the large slip scar they had crossed on their way up. It’s still too early in the season for plants to be flowering, but some of the Senecio were in bud, the first flowers were appearing on the tussock Poa foliosa, and the Luzula or wood rush also had its first tiny flowers.
Denise and Brian were struck by the numbers of both snipe and Antipodes parakeets. They commented on how curious and chatty the parakeets were, approaching very close and then partially hiding themselves behind a piece of vegetation and peering out to see what was going on. The Reischek’s parakeets were more flighty, and flew away as people approached.
Up on the summit of the island, which is a thick fernland, and quite different from the grassy slopes, the pair got a fleeting glimpse of Archway Island, the smaller island next to Bollons, before the mist clagged in again, and they had to make their way back down for their pickup. To make sure the pair got aboard the dinghy quickly Hamish’s instructions to the pair were to ‘jump into my arms!’
On Sunday, the weather was fine, but the northwest wind was forecast to get strong, and Denise and Brian were given just an hour back on Bollons Island again, to gather up some of the lower pitfall traps and tracking tunnel papers, which revealed a few footprints. Both Denise and Brian said the experience of being on Bollons Island was a rare treat, albeit one made more challenging by their sea legs, which gave them a feeling of wobbliness that they could have done without on the island’s sheer sides!