A team of Te Papa scientists recently visited Dusky Sound as the first stage in an investigation of changes in biodiversity since Cook’s visit in 1773. Cook named the area ‘Dusky Bay’ when he sailed past on his first voyage in March 1770, and explored the sound and its wildlife more thoroughly during a 6-week stay three years later. The Resolution and its crew were in Dusky Sound in March-May 1773, during which the naturalists on board prepared the first scientific descriptions and paintings of many New Zealand birds and fishes.
A highlight was our confirmation that broad-billed prions still breed in Dusky Sound, 243 years after Reinhold and Georg Forster described them there in 1773 (we are unaware of any breeding records in the intervening years).
Dusky Sound in southern Fiordland is one of the most remote parts of the New Zealand mainland. First impressions are that nothing has changed since early Māori or Captain Cook entered Tamatea/Dusky Bay. Dense rimu, rata and totara forest rises directly from the shore, and the calm waters support diverse and abundant marine life. But if you know where to look, there is evidence of landmark events, fortunes sought, and battles fought dating back a quarter of a millennium.
Te Papa in Dusky Sound
Our visit had a particular focus on seabirds, which have received little attention in Dusky Sound to date, despite a huge amount of conservation work there in the last 15 years (and previously in the 1890s). Most of this recent effort has been focused on stoat control, kakapo management, and translocation of other forest birds. As a result, many dozens of islands in Dusky Sound are now free of rats and stoats, and we hoped to find what species of seabirds had survived and recovered since being freed from predation pressure.
We were based on the Department of Conservation vessel Southern Winds. The experience and skill of the crew enabled us to safely land on and survey 59 different islands during our 10-day visit.
Early European history
Many of the place names in Dusky Sound were bestowed by Captain Cook, including Indian Island, where the Resolution crew first encountered a Māori family on 7 April 1773. Nearby Luncheon Cove on Anchor Island recalls a feast of crayfish, and it was here that sealers set up camp only 19 years after Cook named the site. Sealing was New Zealand’s first export industry, and Dusky Sound was the prime mainland site for harvesting fur seal skins from 1792 until the last open season in 1946. Luncheon Cove was the site of New Zealand’s first European house, and the site where the first European designed ship was built – the 16-metre Providence, launched in 1795.
Dusky Sound was also the site where pioneer conservationist Richard Henry lived from 1894 till 1908. Based on Pigeon Island, off the south coast of Resolution Island, Henry and his assistants moved more than 700 kakapo and kiwi from the Fiordland mainland to islands in Dusky Sound (mainly Resolution Island), in a valiant attempt to save them from stoats and weasels that had been introduced to New Zealand to control rabbits.
Richard Henry realised that his hard work had been in vain when he saw a “weasel” (probably a stoat) on the shore of Resolution Island in 1900. But his legacy continues. There are now more than 2,300 stoat traps on Resolution Island, with more on the adjacent mainland and on most of the islands that we visited. Kakapo were reintroduced to Anchor Island in 2005, and the island now holds 43% of the world population.
Major findings of the Te Papa visit – seabirds
We were astonished to find 49 petrel breeding colonies, only three of which had previously been reported in publications. The three species found were sooty shearwater (35 sites), mottled petrel (12 sites) and broad-billed prion (2 sites).
Dusky Sound is the type locality for the broad-billed prion (i.e. where they were first described). It was a thrill to find they were still breeding there 243 years after the Forsters reported them.
We also found tawaki/Fiordland crested penguins breeding on numerous islands, with large chicks nearly ready to depart to sea.
Landing on so many islands meant that we were able to gather valuable information on the distribution of land birds within Dusky Sound. This included finding that South Island saddlebacks had colonised an island lying 100 metres off the coast of Anchor Island (where they were reintroduced in 2002) – which must be right at the limits of flying ability for saddlebacks.
We were also surprised at how successfully South Island robins have recolonised islands in Dusky Sound. They were absent before the current stoat control programme started, but were reintroduced to Anchor Island in 2002, and Pigeon Island in 2007. We found robins on 35 different islands, almost all of which have stoat traps on them. This reveals that robins are capable of flying up to a kilometre to recolonise sites cleared of predators,
Perhaps the biggest surprise of our visit was the discovery that two threatened weevil species are not only present in Dusky Sound, but at least one of them is widespread and thriving. Both these flightless species (knobbled weevil and flax weevil) are among the few insects fully protected under the Wildlife Act, and are highly vulnerable to rodent predation. Both species were known from Breaksea Sound to the north of Resolution Island, but neither had been recorded from Dusky Sound. While we found only a single knobbled weevil (Hadramphus stilbocarpae), flax weevils were found on five islands, and their characteristic feeding sign noted on 28 islands – an astonishing testament to the scale of biodiversity recovery occurring in Dusky Sound.
With many thanks to the Department of Conservation for logistic support and permitting – plus the phenomenal effort they are putting into ridding Dusky Sound islands of predators.