Our Changing World: Saving Tara-iti shell by shell

On an overcast winter's day at Bream Bay, about 20 people are doing something that, at first glance, seems a little odd.

They are shovelling shells into hessian sacks and moving them from one part of the beach to another. But the painstaking work has a purpose: creating safe places for tara-iti, New Zealand fairy tern, to nest.

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There are only about 45 of the birds left, making the subspecies one of New Zealand's rarest endemic breeding bird.

Department of Conservation (DOC) tara-iti programme lead Ayla Wiles told Our Changing World that the team was enhancing areas in the back dunes at Waipu to give breeding pairs more options.

"This just gives them nice safe options for nesting, so away from the tide, a bit of protection from storms and that sort of thing."

Tara-iti are mostly white with a black cap, orange bill and orange legs. They currently breed at Waipu Mangawhai, Pākiri Beach and Papakānui Spit at the southern end of the Kaipara.

The preferred habitat is an open sandy area with shell, with enough clear space for the birds to see potential predators. Bits of wood also provide places for chicks to hide from aerial predators.

Getting the recipe right

Creating a nesting site that tara-iti will actually use is not straightforward.

Waipu About-Tern volunteer Robyn Davies said one site created the previous year apparently had too much shell and getting the ratio right is important.

"They're quite fussy when it comes to their nesting site," she said, "If we don't get it right, they don't stay."

The site at Waipu should be perfect, it's protected from high tides, storms and wind, while the nearby estuary gives young birds somewhere to learn to fish.

Signs of success

Wiles said there were signs the approach was paying off.

"Since we've been doing this sort of shell patch creation ourselves, we've seen nest success increase, so fewer nests lost because they are just away from those threats."

DOC has worked on tara-iti recovery since the 1980s, when the population was down to three or four breeding pairs.

Wiles said numbers had slowly increased as conservationists improved both protection in the wild and methods for raising birds in captivity.

One of the techniques involves collecting some of the first clutches laid in a breeding season and taking the eggs to Auckland Zoo, where chicks are hand-reared for their first few weeks. They are then transferred to a release pen, where they learn to fish before fledging.

Meanwhile, the breeding pair whose eggs were removed can lay another clutch.

"We've doubled the productivity for those pairs," Wiles said.

She said that had helped lift the number of fledglings from about six in a season to 12, and in one year as many as 18 or 19.

The team is hoping a milestone could be reached this breeding season: the first surviving female tara-iti raised in captivity may breed.

She had been prospecting at the northern end of Waipu the previous season but had not laid an egg.

"This year could be the year," Wiles said.

Tracking tara-iti's travels

GPS tracking of the birds has also revealed that some tara-iti roam much further than previously apparent.

The birds spend winter around Kaipara before returning to breeding sites, but some younger birds have travelled as far north as Te Paki and Hokianga Harbour. One travelled south to New Plymouth and another went to Pūkorokoro/Miranda on the Firth of Thames in Waikato.

Trackers were initially used on hand-reared birds, but wild males are also now being tagged.

Wiles said comparing the movements of wild and captive-reared birds could help researchers check whether they were behaving in the same ways and reveal previously unknown foraging areas or potential new breeding sites.

There is also hope that, as numbers grow, tara-iti could begin breeding beyond their four current sites.

Wiles said the team was considering a potential habitat north of Ruakākā.

Mangawhai remains the biggest breeding site, with up to eight or nine breeding pairs, compared with about two or three at Waipu. But the smaller sites are important too, she said, because they spread the risk across several locations.

'A messenger' between land and sea

For Ari Carrington, from Patuharakeke Te Taiao unit, the effort is about more than the recovery of one species.

He said tara-iti had not featured heavily in the pūrākau he grew up with, although some people remembered the birds in earlier times.

Working with them provided an opportunity to build and share knowledge within the hapū.

"Whatever's happening on the whenua is happening in the moana, and we must protect both of them," said Carrington.

"The tara-iti is like a messenger in between those."

He said restoring tara-iti also meant thinking about the other species around them, including other manu, skinks and lizards.

"Sometimes we just focus on one species, one atua, one spot when we need to think wider sometimes. If they don't have any whānau, then just like us, they struggle."

Every nest matters

Protecting the birds requires much more than shifting shells.

Around 10 full-time site-based rangers work across the breeding season at nesting and captive-rearing sites. The transcript says nests are checked every day, while other work includes fencing nesting areas, predator control and educating people using the beaches.

Volunteers also help keep watch.

Davies has been monitoring tara-iti for about 16 years and said volunteers check that eggs and chicks are still present and being fed, as well as watching for predator tracks or signs a bird is unwell.

That long association also means getting to know individual birds.

"Each bird that you monitor, it has its own little thing, whether it's the cheeping of the female or the runaway chicks or the male that's very dominant," she said, "They've all got their own personalities."

The stakes remain high.

A third of eggs or newly hatched chicks were eaten by predators last breeding season, although with 11 chicks still fledging, the season was considered a success.

The tara-iti breeding season runs from September to January, with egg-laying expected to begin around the middle of November.

And after years in which the population remained below 40 birds, Wiles is allowing herself some cautious optimism.

"It's good to see the numbers creep up, and like this time next year we could be at 50 if, you know, all goes well."

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