Nests to boost critically endangered tara iti/fairy tern at Waipu north of Auckland

There are just 35 to 39 tara iti/fairy terns in existence. Photo / File

One of the world's rarest birds the tara iti (fairy tern) is being given a helping hand with three new constructed nesting areas north of Auckland.

There are only about 35 to 39 tara iti remaining, all on the beaches north of Auckland and south of Whangārei.

While that number might seem alarmingly low, Department of Conservation biodiversity ranger Ayla Wiles said the birds that once roamed the country had dropped to a frightening 10 individuals a few decades ago.

Major threats to the bird were from predators - mainly cats, ferrets and black-billed gulls - and habitat destruction.

The birds would naturally nest in sand dunes and estuarine areas, havens from storms and king tides, but housing pressures and various developments have increasingly pushed them onto exposed beaches.

The last few seasons had proven devastating for their breeding, with last year just two chicks hatching, and one breeding female dying.

Nests in exposed areas could be blown away by high winds, preventing parent birds finding their eggs, and king tides wash them away.

Beachgoers and motorists who roamed the dunes and upper beach areas also risked trampling their nests.

Staff at work building nesting areas at Waipu Cove, north of Auckland. Photo / Supplied

They also couldn't be bred in captivity as they were very particular about their nests.

To counter all this, Wiles said they were building nesting sites in safe areas away from the beachfronts.

The nesting project at Waipu Cove was the "biggest ever", and involved helicoptering in 130 tonnes of locally-sourced shells to construct three sites.

The work was funded by Te Arai and Mangawhai Shorebirds Trust, established by the owners of the nearby Tara Iti golf course development, as part of its consent requirements, and run with DoC and Patuharakeke Te Iwi Trust.

Patuharakeke Te Iwi Trust's Juliane Chetham said they were pleased to support the kaupapa.

"We consider this to be a contemporary exercise of our kaitiakitanga, helping to protect tara iti, a taonga species.

"It also provides opportunities for our rangatahi to be trained and gain valuable experience in conservation work."

The work was part of a wider three-year-plan developed by the Tara iti Recovery Group, made up by the Te Arai and Mangawhai Shorebirds Trust, hapū Te Uri o Hau, environmental consultants Boffa Miskell and DoC.

The plan aimed to develop further shell patches across all tara iti breeding sites.