Tern of the tide: The breeding grounds of the endangered fairy tern

Thursday, 26 January 2017

The endangered fairy tern is being protected by the Department of Conservation and the NZ Defence Force. (First published January 2017)

Nestled at the entrance to the Kaipara Harbour, New Zealand's rarest bird shares its home with the Royal New Zealand Air Force weapons and bombing test site.

With dangerously low numbers, there are only 40 fairy terns in New Zealand, and six of them live at the Papakanui Spit, off Kaipara South Head, northwest of Auckland.

It is believed that terns once lived along the coasts of the North Island, and on the northeastern part of the South Island, but now they are only found in only four places in Auckland and southern Northland: Kaipara, Pakiri, Mangawhai, and Waipu.

Fairy tern chicks are banded before they learn to fly, so they are easily identifiable.

DOC and Defence Force 4WDs brave the bush, dunes and weather in the search for the elusive fairy tern.

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Wiles keeps her eyes peeled as she surveys the beach for a tern, after he was not in his shell patch nest.

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While the birds are New Zealand's most endangered species, things have been worse for the tiny bird with a white body and light bluish grey wings and a prominent black ring around its eyes like eyeliner, with only three pairs in 1984.

At the rugged South Head of the Kaipara Harbour.

The numbers didn't improve much in the 1990s - fairy tern numbers barely scraped double digits.

Since DOC began their nest protection programme, the number of fairy terns has risen from that low of just three breeding pairs up to 12 pairs this year, as some of the birds are infertile.

Six of only forty remaining fairy terns live at Papakanui Spit, in the rugged South Head of the Kaipara Harbour.

Khaki-clad fairy tern godmother, Ayla Wiles, has been living on a Defence Force base since October.

Wiles spends her days ensuring the six birds at Papakanui Spit have the best shot at breeding, hatching and fledging chicks, in her role as fairy tern warden for the Department of Conservation.

She watches and waits for the terns every day, searching for nests, locating eggs, checking traps, and waiting until the tiny fluffy chicks have enough wings to fly.

Her day starts at the range warden base, she then makes her way down to the spit. The 4WD bumps and trudged down dirt tracks through Woodhill Forest to the beach. We stop the car twice to let wild deer pass.

Ominous signs warn people to turn around: 'Defence Force Weapons Training Area - Trespassers will be prosecuted.'

Locked gates break up kilometres of road off the beaten track.

From a lookout overthe dunes and the Papakanui spit, finding the birds seems like an overwhelming task.

Now that the breeding season is winding down and Wiles just has one chick to mind, some of the weight has been removed from her shoulders.

It's a lot of pressure trying to make sure you find the eggs and get them to hatch, she says.

'They've just got so many things working against them out here.'

Wiles, who has a masters degree in conservational biology, will stay until the chick is able to fly in February - after that, her work is done.

But it's no easy feat getting to that stage.

Despite there being only six terns at the Papakanui, they're incredibly territorial and nest kilometres away from each other - which makes things tricky for the person monitoring them, Wiles says.

The wind whips the dunes constantly, moving nests and burying eggs.

If a nest is in a bad spot, it's up to Wiles to change it. She sits by the nest for an entire day, moving it as little as one metre an hour, trying not to disturb it too much.

Anything more than that, and the tern could lose their nest entirely, she says.

'You've gotta stay one step ahead of the dune.'

'It's really rewarding to get an egg after all of that.'

Nearby, on a marshland, terns often come to feed, but not today.

Fairy tern chicks are reliant on their parents for the first year of their lives, and it takes a long time before they learn to survive on their own, like how to fish for themselves, Wiles says.

'It's incredibly hard for a human to teach a bird how to fish,' she joked, but it seems like she would if she could.

Despite population numbers being dire, fairy terns can live to be 19 years old.

The oldest bird at the Kaipara site, Bertram, is 13, and has his son and 'grand-chick' nestnearby.

Infertility is an ongoing issue for terns.

'Because there are so few birds remaining, they're inbreeding, creating a mutation in the genetic line.'

Though they're trying to repopulate, she says , they often aren't fruitful.

Twenty-two eggs were laid in total this season. Ten were infertile, six were lost to predators and six hatched.

The only chick still at Kaipara was born on January 12.

The other two eggs were given to 'foster' parents and moved to Mangawhai and Waipu.

The Papakanui breeding site is far less ideal than where other terns live, she says.

As it is on the 'wild West Coast' the spit is exposed - heavy winds change the sand dunes daily, similarly to the marshlands, she says.

All it would take is a king-tide to sweep in and entire nests could be washed away.

Further down the spit, racing down the sand as the tide goes out, terns make their nests in shell patches on the sand. They disguise their small white eggs close to the surface in a pile of crushed shells.

After checking their nests, the terns are still nowhere to be found.

The other breeding pair are at the spit and are nested in a 'terrible' spot this season, according to Wiles. They just pick their spot and that's it, she says.

'Because of humans and predators there's really just nowhere else for them to go.'

Nearby Woodhill Forest is a haven for pests and part of her job is maintaining and checking traps daily.

Stoats, ferrets, weasels, hedgehogs and rats all destroy the tern's habitats.

DOC have made a 'trapping halo,' which starts 90 kilometres away from the nesting area, but it's not foolproof, as some predators still make their way down to the beach.

She says they're lucky at Papakanui that people don't have access to where the terns live which is a major issue in Mangawhai and Waipu - where they nest in open, public beaches.

'You can fence areas off, but people still walk through nests.'

Wiles says though it may seem like an unlikely marriage, having the terns nest in a Defence Force protected area gives them a better shot of survival.

'I'd much rather have the Defence Force own the land than have it be open to the public,' Wiles says.

Defence avoid weapons tests around breeding season, and ensure they stay right away from the spit - testing higher up in the dunes at Waionui Inlet.

It's an unusual job - and one that gives Wiles space from civilisation and a lot of time alone in the fresh air.

But that's not a bad thing, she says.

After we've spent most of the day trying to track down these elusive birds, with no luck, it's clear - they keep too busy for her to ever be bored.