By Kate Hebblethwaite, Community Ranger
Retracing Captain Cook’s Dusky Sound voyage has resulted in some amazing discoveries.
In November last year, DOC staff joined a Te Papa team in Dusky Sound to retrace the voyage of Captain Cook.
Te Papa’s visit, linked to the 250th anniversary of Cook’s 1773 voyage, aimed to document changes in the biodiversity of Dusky Sound since Cook’s five-week sojourn there.
It included visiting sites described in the ship logs, surveying bird diversity and collecting invertebrates and plant samples.
Fish and marine invertebrates will be surveyed and sampled on a later visit in 2017.
Using the DOC boat Southern Winds, and with the able assistance of rangers Hannah Edmonds and Max Smart, the Te Papa team visited 59 islands in the greater Dusky Sound area.
The team was hugely impressed by the scale of DOC’s pest control work, and the conservation gains made here in the last 15 years.
Te Papa’s Curator of Vertebrates Colin Miskelly said the level of DOC’s island predator control in Dusky Sound would have been a significant factor in the remarkable discoveries made during the short visit by his team to each island. In many cases the work was undertaken with support from local organisations and funders.
Saddleback, returned to pest-free Anchor Island in 2002 and 2004, were discovered on an island 100 metres away from Anchor.
Meanwhile, the rare knobbled weevil and flax weevil were discovered, with the flax weevils found throughout Dusky Sound.
Breeding colonies of broad-billed prions were also found – the first breeding record in Dusky Sound since Cook’s visit in 1773.
The project findings are an important boost for the DOC Te Anau biodiversity team, filling a large information gap about seabird and invertebrate distribution, and indicating the area’s island predator control programme is achieving significant results.
A full report is currently in development; however, Te Papa have shared with us a summary of some of the most noteworthy findings of the trip.
Colin has blogged about the visit on behalf of Te Papa. Read his ‘Dusky Sound – rich in wildlife and history blog.
Burrow-nesting petrels were found on 44 islands, with sooty shearwater the most numerous and widespread species (35 sites, 21,425 burrows estimated).
Mottled petrel was the second most numerous and widespread species (12 sites, 5530 burrows).
Most significantly, the team confirmed that broad-billed prions are still breeding in Dusky Sound (2 sites, 560 burrows).
Grey-backed storm petrels were spot-lighted at night at two sites – 2+ birds off Oke Island, Wet Jacket Arm, and at least one bird off the Seal Islands.
These sightings, along with multiple records throughout Fiordland, add to the likelihood that this cryptic species breeds in low numbers somewhere within the national park.
Its nearest known breeding grounds are on the Chatham, Auckland and Antipodes Islands.
Two rare, flightless weevils are known from islands at the entrance to Breaksea Sound and elsewhere, but had not previously been recorded from Dusky Sound.
Flax weevils (Anagotus fairburni) have a relictual distribution on islands from the Three Kings south to Stewart Island, but had not previously been found in Dusky Sound.
The team found evidence of their presence on 28 islands, with live animals found on three islands, and parts of dead animals on another two islands.
The team was particularly surprised to find feeding sign on Indian Island, which has been recently re-invaded by rats.
The knobbled weevil (Hadramphus stilbocarpae) was originally known from the Snares Islands, some of the muttonbird islands south-west of Stewart Island, and Solander Island, where it feeds on two species of Stilbocarpa (punui).
Within Fiordland it feeds on Anisotome lyallii (Breaksea Sound Islands and Secretary Island).
Its feeding sign is not so obvious as for the flax weevil, and the team confirmed its presence on just the one islet within the Seal Islands.
The most notable land bird find was saddleback on an island 100 m from Anchor Island (an unnamed island 79 m high, between Seal Islands and Many Islands).
A pair was seen, and at least one other bird was calling.
The team also recorded South Island robin on 35 islands.
No lizards were seen, but the conditions were not the best for finding them.
The two most promising islands in terms of location, habitat and predator history are the northernmost islet in the Seal Islands, and the isolated island midway between Anchor Island and Parrot Island.