‘Where once the Karepiro chenier hosted dotterel and oystercatcher nests there could soon be sandcastles, and how many cats?’ Pat Baskett looks at our ongoing contribution to the Sixth Extinction.
It’s tempting to describe this breeding season of the tūturiwhatu (NZ dotterel) at Karepiro Bay on Auckland’s North Shore as a good one. Their bright orange breeding plumage is easily visible. Less conspicuous among the shore’s stones and shells is the newly hatched pale chick of one pair’s second brood.
Two dotterel pairs have already raised one fledgling each and these have now departed for richer shores. Two tōrea pango (variable oystercatcher) chicks reared by one pair are sticking close by.
Bernard Michaux, who’s been monitoring birdlife at the site for the last 12 years calls it a “baby boom”.
Guesses aren’t invited about the fate of the hatchlings that might have emerged from clutches that usually number three eggs.
Both species are endemic, meaning they are found only in New Zealand. But while the oystercatcher is thriving nation-wide, the dotterel is endangered. Once widespread and common, they now number about 2500 and are considered more at risk than some species of kiwi.
Both birds make their nests just above the high-water mark on sandy beaches. A dotterel nest is a mere declivity in the sand, indistinguishable from the surrounding twigs, dried grass and pebbles. Volunteers have roped off the nesting areas at Karepiro and monitor traps for rats, mice, stoats, weasels, hedgehogs and, until recently, for cats.
Dogs aren’t allowed, even when leashed.
The area offers multiple rewards for birdwatchers. Every summer up to 200 bar-tailed godwits arrive from Alaska. They share the mudflats with native pied stilts (poaka), caspian terns (kāhawai), reef and white-faced herons (matuku moana), pied shags (kāruhiruhi) and spoonbills (kotuku ngutupapa). A pair of rare brown teal (pāteke) have recently disappeared from a nearby salt marsh but birders with patience might spot a banded rail (moho pererū).
The sandbanks at Karepiro and those at the Weiti and Okura river estuaries which fringe the Long Bay Okura Marine Reserve, have other claims for protection. They’re known as cheniers – internationally significant landforms consisting of shell barriers or ridges that have built up over centuries. They often lie like long waves over the mudflats and are valued not only for their rich ecosystems and the roosting places they offer wading birds, but for the information they provide about sea level variations and changes in the marine environment.
While sandbanks are as common as sandflies, cheniers in New Zealand are found only in the Hauraki Gulf. The most well known are those that stretch over the mudflats at the Pūkorokoro Miranda bird sanctuary. These are recognised world-wide for their unusually wide expanse and, of course, for the thousands of birds that migrate there each year.
Miranda, where the Shorebird Centre is run by the Miranda Naturalists’ Trust, is safely out of harm’s way, a 90-minute drive from the CBD down the east coast towards the Firth of Thames.
The cheniers that border the Long Bay Okura Marine Reserve lie perilously close to civilisation and their precious avian inhabitants have no more protection than the predator traps on the shore and the signs banning dogs.
The closure of the Okura Bush Walkway almost five years ago to protect the bush from kauri dieback may have extended the birds’ residency by drastically reducing the numbers of visitors. Walkers used to flock in their hundreds to enjoy the hour’s walk through mature nikau, puriri and kauri to Karepiro and not all were mindful where their feet trod, or of the effects of human incursions on wildlife sensibilities.
The Okura walkway is administered by Ngāti Manuhiri and the Department of Conservation, and will remain closed for this summer.
The public walkway along Karepiro Bay belongs to the Auckland City Council. Predator control of the area that includes the three cheniers and the adjacent bush is undertaken by the local organisation of volunteers, Friends of Okura Bush (FOOB). Last year’s tally included an impressive 55 weasels, 17 stoats, 377 rats – Norwegian and ships – 189 possums, and 55 hedgehogs. Mice were the biggest bounty, numbering 870.
Cats remain the predators of exception.
Domestic and wild, cats are at least as lethal as stoats or rats but the old issue of trapping pets is as hot here as in multiple places where volunteers labour to keep wildlife flourishing. Last year, after motion cameras detected cats on the nesting cheniers, FOOB contacted council for advice and were told community trapping of cats, even live, had to stop.
FOOB spokesperson Joanna Crawford describes the huge effort of time and energy that was involved. “We had to carry them, often several kilometres in their cages, and then to a vet to check whether they were micro-chipped and registered. Then we returned them to their owners.”
Only feral cats were euthanised.
“With much anguish we’ve ceased operations,” Crawford says.
It’s not just birds, she points out. Cats have a negative impact on native lizards, frogs, bats and invertebrates.
Council’s principal advisor biosecurity, Dr Imogen Bassett, offers cold comfort: “We carefully manage our cat control operations to ensure we are able to undertake these activities in places with the greatest ecological need, while not risking the trust of pet owners. While this site does not currently meet those thresholds, we will continue to monitor and review the situations.”
As long as micro-chipping is optional and there are no rules limiting where a cat can roam, council’s response begs the question of the trust conservationists can have in cat owners to recognise the threat their pets pose. Micro-chipped cats have been picked up having roamed more than five miles from their home.
The other question relates to how ‘ecological need’ is assessed. Council’s designation of the areas of the cheniers as “open space – conservation zone” appears inadequate. Their refusal to undertake trapping itself is one thing, but stopping community groups from doing so is another.
Part of this may be to do with the need to take into account, over and above the humane treatment of all animals – the sensitivity of pet owners to the way their cats are handled.
Bernard Michaux has a strong response to the council’s ban: “Hundreds, if not thousands of volunteer hours have been negated at a stroke by these decisions.”
Behind Karepiro beach, a gated community extends across 93 gently sloping mown hectares. The views, the quiet and the closeness to the beach at Karepiro are a vestige of the wisdom of the former Rodney Council who zoned it for country living. About 30 of the 150 houses allowed have been built.
Back from the gate, at the foot of a steep track stands a dilapidated sign. It announces Weiti Village: apartments, town houses, terraced houses – now. The hills are a mess of pampas grass and weedy trees but according to the website, construction is due to commence this year. Where once the Karepiro chenier hosted dotterel and oystercatcher nests there could soon be sandcastles, and how many cats?
Protection requires resources. It also requires compromise and vision.
New Zealand, with one of the world’s highest extinction rates, continues to contribute to the Sixth Extinction that scientists tell us is well underway. The effects of climate change will exacerbate this as temperatures increase and creatures seek new habitats.
Population pressures around Auckland make every patch of indigenous biodiversity – and geological rarity – precious.