By Alison Ballance
The Bounty Islands, according to the Department of Conservation ‘are a bare and wind swept group of 22 slippery granite rocks 700km east-south-east of New Zealand. They’re the most remote and least visited of New Zealand's subantarctic islands, having no safe anchorage or easy landing sites.’
During October-November 2014 I was part of a Department of Conservation team that visited Antipodes Island and the Bounty Islands to count seabirds. At the Bounty Islands we were counting Salvin’s albatrosses and erect-crested penguins under the watchful eye of Bounty Island seabird expert Jacinda Aimy, from the Department of Conservation. We carried out counts of birds in study areas on Funnel and Depot islands, and all the birds on Proclamation Island.
According to the most recent risk assessment of the impact of fishing-related mortalities on 70 species of seabirds that breed in New Zealand, Salvin’s albatrosses have the second highest risk. More than 400 of them are estimated to die each year, mainly by getting caught in the small vessel bottom longline fisheries. Counting breeding birds on the ground is an important way of seeing if these fishery-related deaths are affecting the population.
This was Jacinda’s fourth trip to the Bounties. She had counted Salvin’s albatrosses and erect-crested penguins there before - in 1997, 2004 and 2011. In 1997 she joined the late Gerry Clark on his 11-metre (including bowsprit!) yacht the Totorore to reach the islands, and camped ashore on Proclamation Island for several weeks, a feat she repeated in 2004.
There was a 14% decline in the number of nesting albatrosses counted between 1997 and 2004 (about 3000 nesting pairs in 2004), while the erect-crested penguin counts were almost identical (2775 nesting pairs in 1997 compared to 2766 in 2004). Salvin’s albatross numbers decreased by a further 14% between 2004 and 2011, and erect-crested penguin numbers declined by 7% for the same period. By comparison, the 2014 count revealed that albatross numbers on Depot Island had increased by 18%, and on Proclamation Island by 22%. Erect-crested penguins had increased by 1% between 2011 and 2014.
Salvin’s albatrosses breed every year, but very little is known about the details of their breeding – for example, the exact length of incubation is not known, nor is time to fledging, as no one has ever spent a whole breeding season observing the birds. Some variation is expected in counts between years, and although two successive declines were of concern, the recent increase in numbers is a positive sign.
The 2014 Antipodes Island expedition included counts of erect-crested penguins following large peat slips on the island in January 2014.
In 2012 I joined an expedition to the Auckland islands to count yellow-eyed penguins, which showed a decline of about 30% in penguin numbers from the only previous count in the late 1980s.