Tag Archives: Codfish Island

Whenua Hou / Codfish Island – 1934 and 2011 – In the footsteps of Edgar Stead (Part 4)

As part of a project to publish the wildlife diaries of Edgar Stead, I am revisiting some of the islands that Stead camped on during the period 1929-1947. The main focus is describing how the ecology of the islands has changed since Stead’s time. The visits also provide an opportunity to take photographs to illustrate the diaries.

Stead and his companions Major Robert Wilson and Percy Elworthy were the first naturalists to visit 1400 ha Codfish Island, north-west of Stewart Island. They camped at the western end of Sealers Bay 20 Dec 1934 to 7 Jan 1935, and used a small boat to explore the island and its offshore islets.

Edgar Stead's 1934-35 camp on Codfish Island. Photo: Edgar Stead. Macmillan collection, 2001.59.116, Canterbury Museum. Permission of Canterbury Museum, Christchurch, New Zealand must be obtained before any re-use of this image.

Location of Edgar Stead's 1934-35 campsite on Codfish Island (the end of Sealers Bay is visible at lower right). Photo: Colin Miskelly, Te Papa, December 2011

The major discovery of their expedition was that Codfish Island was a breeding site for Cook’s petrel, otherwise known only from Little Barrier Island 1200 km to the north. Stead estimated 30,000 to 40,000 Cook’s petrels to be on the island, and noted that they were being killed by weka (a predatory rail native to mainland New Zealand, but introduced to Codfish Island). By the late 1970s, Cook’s petrels were approaching extinction on Codfish Island, prompting the Wildlife Service to eradicate weka, along with brush-tailed possums which had been introduced from Australia for fur-trapping.

Cook's petrel at burrow entrance at night, Codfish Island. Photo: Colin Miskelly, Te Papa, December 2011

Edgar Stead also noticed that the fernbirds on Codfish Island were darker than those on other islands off Stewart Island. In 1936 he named the Codfish Island fernbird Bowdleria punctata wilsoni in honour of his friend and companion.

Codfish Island fernbird exiting nest among cocksfoot, Sealers Bay, Codfish Island. Photo: Colin Miskelly, Te Papa, December 2011

Codfish Island is famous as the most important site for the kakapo recovery programme. It is a strictly controlled nature reserve, and I am grateful to the Department of Conservation (DOC) and the Whenua Hou Advisory Committee for granting me the privilege to visit. My five companions on the island were all DOC staff or volunteers working with kakapo. These critically endangered flightless parrots were transferred from Stewart Island (where they were being killed by feral cats) to Codfish Island from 1987 onwards.

Kakapo at night on Codfish Island. Photo: Colin Miskelly, Te Papa, December 2011

Further information on the wildlife of Codfish Island is posted on 
http://www.birdingnz.net/forum/viewtopic.php?f=3&t=1516
and
http://blog.tepapa.govt.nz/2011/12/13/riders-of-the-storm-the-severely-depleted-next-generation/

Other posts on this topic:
Taranga / Hen Island – 1933 and 2010 – In the footsteps of Edgar Stead (Part 1)
Nukuwaiata / Inner Chetwode Island – 1936 and 2011 – In the footsteps of Edgar Stead (Part 2)
KundyIsland – 1929 and 2011 – In the footsteps of Edgar Stead (Part 3)
Rerewhakaupoko / Solomon Island – 1931 and 2012 – In the footsteps of Edgar Stead (Part 5)
Taukihepa / Big South Cape Island – 1931 and 2012 – In the footsteps of Edgar Stead (Part 6)
Pukeokaoka / Jacky Lee Island – 1932 and 2012 – In the footsteps of Edgar Stead (Part 7)
Green Island – 1941 and 2012 – In the footsteps of Edgar Stead (Part 8)
Ruapuke Island – 1941 and 2012 – In the footsteps of Edgar Stead (Part 9)

By Colin Miskelly, Curator Terrestrial Vertebrates

Riders of the storm – the severely depleted next generation

2011 was a terrible year for New Zealand seabirds. The Rena oil spill in October received the most media coverage and provided dramatic images (see Rena oil spill blogs). More insidious were the impacts of the Japanese earthquake and ensuing tsunami in March. A plume of radioactive fallout from the crippled Fukushima Daiichi nuclear power plant contaminated the North Pacific feeding grounds of several New Zealand-breeding species, including flesh-footed shearwater, sooty shearwater (muttonbird), Buller’s shearwater and mottled petrel.

Fluttering shearwaters killed by the Rena oil spill. Photo: Colin Miskelly, Te Papa

However, the most extreme mortality event for any single species was a severe July storm estimated to have killed several hundred thousand broad-billed prions (see Riders of the storm – thousands of seabirds perish on New Zealand shores). The broad-billed prion is a poorly studied species. There are no well-monitored populations, and so there are few opportunities to determine the impact of the storm at a population level.

Prions killed during the July 2011 storm event. Photo: Alan Tennyson, Te Papa

In the New Zealand region, broad-billed prions breed on small islands in the Chatham Islands, Fiordland, and around Stewart Island, and on the Snares Islands. A few breed on islets and stacks off Whenua Hou/Codfish Island, north-west of Stewart Island. I visited tiny Trig Island (a known broad-billed prion breeding site) there on 8 December, and found a ghost town.

Trig Island, off the east coast of Codfish Island. Photo: Colin Miskelly, Te Papa, December 2011

The peaty soil was honeycombed with an estimated 500 burrows, but 90% looked like they had not been visited at all this season. In early December, most burrows should contain large chicks, but I found only four in about 50 active burrows inspected, and estimated only about ten chicks to be present on the island (i.e. about 2% of burrows contained chicks).

Broad-billed prion chick, Trig Island, Codfish Island, December 2011. Photo: Colin Miskelly, Te Papa

The storm that killed so many broad-billed prions hit 6 weeks before broad-billed prions begin to lay. The large number of active burrows on Trig Island that did not contain chicks may be due to an imbalance in the sex ratio of birds that survived the storm, or those that lost a mate may not have had time to find a new one before it was time to breed.

Feather samples taken from the four chicks handled, along with older skeletal remains found on the island, will be used as part of a Te Papa genetic study seeking to determine where the vast numbers of birds killed in July came from. Efforts will be made to collect genetic samples from other breeding sites as part of this study.

Additional information on the wildlife of Codfish Island can be found on
http://blog.tepapa.govt.nz/2011/12/13/codfish-island-1934-and-2011-in-the-footsteps-of-edgar-stead-part-4/
 and
http://www.birdingnz.net/forum/viewtopic.php?f=3&t=1516

By Colin Miskelly, Curator Terrestrial Vertebrates

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