Ten of New Zealand’s most endangered species for 2020

How do you pick what to protect in a country with 4000 threatened plants and animals, asks Michael Neilson

Ma¯ ui’s dolphin is held up as the poster child of New Zealand’s endangered species, but the mammal is far from the only species struggling to cope in New Zealand’s water, forests and rivers. These are the 10 of the country’s native species to keep an eye on in 2020 as they face the biggest fight for survival.

In a country with 4000 threatened species, conservation in New Zealand is often about picking winners.

What makes our species so special is the number that are native — found nowhere else in the world largely because of the millions of years our land spent in happy isolation.

But that isolation is something that has made so many of our species vulnerable.

In 750 years since humans arrived, bringing various predators along with them, New Zealand lost a third of its indigenous land and freshwater birds, around 18 per cent of endemic seabirds, three of seven species of frogs, at least 12 invertebrates, up to 11 types of plants, and a fish, a bat and perhaps three known reptiles.

Some of the most threatened species today are well-known, such as ma¯ ui dolphins and ka¯ ka¯ po¯ , but others are also clinging to survival.

There are, for example, as few as 200 Chatham Island ta¯ iko remaining. In Northland, only 13 Bartlett’s rata are left.

The Department of Conservation’s budget and energy can extend only to active interventions for a few hundred of the remaining endangered species — the exercise involves a careful balance of funding, community input, national identity and research.

An additional $76 million in the Government’s budget over the next four years to tackle the biodiversity crisis has seen an increase in interventions.

DoC ka¯ ka¯ po¯ technical adviser Daryl Eason said what made the unique parrot so special was that it had no close relatives, and also poor breeding and genetics, so if it was left to its own devices it would most likely become extinct.

Meanwhile, some other endangered species had more varied and resilient genetics, meaning they could perform well provided there was appropriate predator control.

Last summer’s prolific rimu fruiting saw the greatest ka¯ ka¯ po¯ breeding season since the intensive management programme began back in 1995, with 72 chicks reaching an age when they could leave the nest (the previous highest was 34).

But the fungal infection Aspergillosis, discovered on island Whenua Hou in July, ended up killing nine ka¯ ka¯ po¯ from the 2019 cohort — two adult females and seven chicks.

Eason said the situation was still “very good” for the endemic parrot, but DoC would be keeping a close eye on what caused the infection outbreak through 2020 and beyond.

Along with DoC’s work, Eason said programmes like Predator Free 2050 and backyard trapping initiatives would all help to turn around the situations for New Zealand’s threatened species.

“Ka¯ ka¯ po¯ were once found all over New Zealand. The habitat is there, so if we are really able to boost our predator control then they should be able to return to the mainland.”

10 endangered species to keep an eye on for 2020 and beyond:

1. Tara iti/New Zealand fairy tern Population: 35-40

Found: Northland and north Auckland beaches Threats: Predators, habitat loss and human disturbance

With fewer than 40 birds, the tara iti is critical despite intensive management and has teetered on the brink of extinction since the 1980s.

While its population might seem alarmingly low, the number of birds that once roamed the country dropped to a frightening 10 individuals a few decades ago.

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

The birds would naturally nest in sand dunes and estuarine areas — which are havens from storms and king tides — but housing pressures and property 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. In the previous year five chicks fledged.

Nests in exposed areas could be blown away by high winds, preventing parent birds finding their eggs.

King tides could also wash them away.

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

Various projects are underway to restore nesting sites around the Kaipara Harbour, and Mangawhai, Te Arai and Waipu beaches. 2. Ka¯ ka¯ po¯ Population: 210 birds (November 2019) Found: Whenua Hou/ Codfish Island and Anchor Island Threats: Habitat loss and predation by rats, cats, and stoats

The flightless “parrot of the night” was once plentiful and with few natural predators nested at ground level. This made it vulnerable to introduced predators and was now classed as “nationally critical”.

The bird only survives on predator-free island sanctuaries and receives some of the most intense protective measures. All birds carry radio transmitters and are intensively monitored and managed.

A bumper breeding season this year saw a record 72 chicks leave the nest, but fears were raised for the species after the fungal infection Aspergillosis was discovered on Whenua Hou in July.

By December the infection had killed nine ka¯ ka¯ po¯ .

Still, the species is in its best shape in years and DoC staff will be keeping a close watch on fledgling chicks ahead of the next breeding season when the rimu tree next fruits.

3. Chatham

Island ta¯ iko Population: 200-250 Found: Chatham Islands Threats: Predation by cats, pigs, weka and rodents

The Chatham Island ta¯ iko is one of the rarest seabirds in the world, with just 200-250 thought to exist. About 35 breeding burrows are currently known.

They breed only in dense forests at the southern end of main Chatham Island.

During the breeding season, the birds feed mainly south and east of the colonies, ranging thousands of kilometres.

During the winter exodus, they disperse widely across the Pacific Ocean from the Tasman Sea to South America, and into tropical seas.

An intensive conservation programme is run annually to protect this summer-nesting seabird. 4. Kak¯ı/black stilt Population: 150 Found: Mackenzie Basin, Canterbury Threats: Habitat loss due to farming and hydroelectric development, predation by feral cats and ferrets, human interference

Once the common stilt of New Zealand, the black stilt is now critically endangered, with a breeding population confined to the Mackenzie Basin of South Canterbury and North Otago.

DoC has intensively managed the highly-threatened birds since 1981 when their population declined to a low of just 23.

There are now 128 adult kak¯ı living in the wild.

Despite intensive management and a captive breeding site near Twizel, they remain the world’s rarest wading birds.

Nearly all wild black stilts are the result of intensive management, especially captive management.