Storm petrel breeding near Auckland

Researchers were elated to find the sparrow-sized New Zealand storm petrel, thought extinct until 2003, breeding on Little Barrier Island (Hauturu) in the Hauraki Gulf Marine Park.

Dr Steffi Ismar in February  with the first New Zealand storm petrel captured on  land. Photo Martin Berg

Dr Steffi Ismar in February with the first New Zealand storm petrel captured on land. Photo Martin Berg

The team of researchers, led by Chris Gaskin, Important Bird Area (IBA) programme co-ordinator for Forest & Bird and Dr Matt Rayner from the University of Auckland, found the breeding site 50 kilometres from Auckland city during an expedition last summer.

The seabird is listed as critically endangered by the International Union for Conservation of Nature (IUCN), and finding breeding sites is vital for their conservation. Three specimens of the diminutive 35-gram seabirds were collected off New Zealand in the 1800s and are in museums overseas. Since its rediscovery in 2003 there has been speculation about where the storm petrel breeds. 

The team camped on the Poor Knights Islands, Mokohinau Islands and receivers to zero in on the breeding site. “It’s like looking for a needle in the haystack,” says Chris. 

A critical breakthrough came last year when the project team found brood (incubation) patches on birds caught at sea. This showed when New Zealand storm petrels incubate their eggs and the best time to find breeding birds on land.

 This year 24 birds were caught at sea using specially designed net guns and small one-gram radio transmitters were fitted to each bird. Automated receivers narrowed down the search. Team members at a remote camp on the north coast of Little Barrier Island and from boats used handheld receivers and spotlights. They confirmed that birds were coming ashore under the cover of darkness and moving inland. Birds were also detected from other parts of the island, including the summit ridges, and the search area was moved. 

The prospect of looking all over the island for the birds was daunting. Team members Forest & Bird Otago/Southland Field Officer Sue Maturin and partner Graeme Loh picked up a signal of a bird in the forest and others were able to get a clear fix on the site. 

“That site is being monitored. It is very fragile,” says Matt. “We are using automated equipment for the most part and maintaining a hands-off approach, although team members visiting the vicinity have also been keeping watch.” 

Chris says other birds have been discovered on the ground. “Team members have seen these small pelagic seabirds flying in kauri and hard beech forest at night,” he says. The island’s DOC ranger, Richard Walle, found a second breeding site further up the same valley during daytime searches using telemetry. 

Aerial surveys tried to establish the distribution and size of the population but turned up nothing new. Members of the research team will spend time on the rugged, forestclad island until late May when chicks leave the island at the end of their breeding season.

“Finding these breeding sites is a brilliant result for our dedicated and enthusiastic team,” says Chris. “It’s been hard going back to our day jobs – team members volunteered their time. There will be more to discover about these birds. This season’s work is far from finished; and we’re already looking ahead to future research work.” 

Locating the breeding ground is internationally significant and further highlights the importance of the Hauraki Gulf Marine Park as a globally significant biodiversity hotspot.

The project was funded this year by grants from BirdLife International Community Conservation Fund, Forest & Bird Central Auckland Branch, Mohammed bin Zayed Species Conservation Fund, The Little Barrier Island Hauturu Supporters Trust and ASB Trust, Auckland Council and Peter Harrison/Zegrahm Expeditions, with further support from the Department of Conservation, Hauraki Gulf Forum and Landcare Research.