Where are all the spotted shags?
Seabird scientists are creating a fake home for shags on the Noises, an island group off the coast of Auckland, in the hope that the Hauraki Gulf’s rapidly diminishing spotted shag population will be fooled into thinking it’s a great place to start a family.
“Let there be poo!” shouts seabird biologist Matt Rayner, splattering paint across the lichen-clad clifftop. Clinging to a narrow ledge, ten metres above the surging sea, he drizzles an abstract painting of white squiggles from a plastic bottle.
Perched on a rocky outcrop, ecologist Tim Lovegrove carefully weaves a nest from kelp and seagrass. Beside him, a speaker blares raucous bird calls into the wind. The spotted shag resting on a nearby pinnacle remains unmoved, staring blankly out to sea.
“Turn up the volume!” commands Rayner. “What are you looking for if you’re a teenage shag? Are you looking for the quiet colony or are you looking for the party colony? Let’s make it loud, colourful, attractive!”
On the northeastern side of Otata, one of the Noises islands, Lovegrove and Rayner are constructing a fake spotted shag colony, complete with roosting birds, handmade nests, recorded calls, and imitation guano.
It’s February, hot and hazy, and on either side of the colony, the sea is a disconcertingly long way down.
Spotted shags used to breed here. They are New Zealand’s only cliff-nesting birds, so this spot wasn’t easy to get to. To reach it, the team floated gear from boat to shore on a stand-up paddleboard, then hauled it up onto the rock stack. (The alternative involved bush-bashing across the island and abseiling down a steep slope.)
The colony construction team consists of Rayner, the land vertebrates curator at Auckland Museum, Lovegrove and Todd Landers from Auckland Council, and Rod Neureuter, one of three siblings who own the Noises.
Rayner bounds down the gut, leaps into the water with his clothes and shoes on and dog-paddles across to the next rock stack, holding his paint bottle aloft. Then he clambers up to the last dummy bird to apply more fake poo.
“I’ve got years of experience building shaggeries,” he says, giving a final squirt of paint.
He’s joking. He hasn’t done this before—no one has. Fake birds and recorded calls have been used to attract gannets with mixed success. (On Mana Island, a lone gannet, Nigel, spent five years courting one of the 80 concrete decoys, carefully making her a nest, but died just weeks after some real-life gannets finally turned up.) This hasn’t yet been tried with any cormorant species.
The nine dummy shags bolted onto the rocks here were modelled on museum specimens, 3D-printed, then painted by volunteers to match the species’ elegant plumage. Wooden stares aside, they’re surprisingly convincing.
“Hopefully they’ll fool the real thing,” says Lovegrove.
Spotted shags, or pārekareka, are common across the South Island and off the coast of Wellington, and once numbered tens of thousands in the Hauraki Gulf. But in the early 1900s, as Auckland grew and fishing began to take a toll on marine life, shags were decimated by fishermen who incorrectly regarded them as competitors—or convenient practice targets.
“I vividly remember, 40 or more years ago, cruising along the coast of Waiheke in the Hauraki Gulf on one of the large yachts of those days,” wrote the naturalist Geoffrey Armstrong Buddle in his 1951 book Bird Secrets. “Spotted shags, not in those days protected, were flying past in a constant stream all the afternoon. Two members of the crew armed with shotguns amused themselves for hours practising on the flying birds: shooting went on till all cartridges were expended and probably a hundred or more dead or dying birds were lying in the water.”
By the 1930s, the population had crashed to just a few hundred birds in two colonies. In 1931, shooting them was banned, and over the following half-century, the species slowly recovered. Surveys in the 1960s counted 2000 pairs breeding in the Firth of Thames, along the islands on the inside of the Coromandel. In the 1970s and 80s, there were also colonies on Waiheke Island, the Noises, at Bethells Beach/Te Henga, and at Girdwood Point, south of Waikato Heads.
Theoretically, they should be doing fine. But spotted shags are now in trouble again, and scientists don’t know why. Over the past few decades, all those colonies have disappeared but one. The shags’ last stronghold is Shag Island/Tarahiki, off the east coast of Waiheke Island. Two tiny satellite colonies on Waiheke’s northeastern tip bring the total population to perhaps 300 pairs.
Meanwhile, recent DNA studies suggest these Auckland shags are genetically distinct from the southern birds, and may even be a separate subspecies (see sidebar – The Shag Menace).
In August, the height of the breeding season, I join Rayner and Lovegrove on a bird survey, an attempt to count the last known spotted shags in northern New Zealand.
It’s a glassy, bluebird day on the gulf as we zoom towards predator-free Tarahiki in the harbourmaster’s speedboat. Perhaps the weather explains the dozens of recreational fishing boats we see on the way. (“Must’ve all called in sick,” mutters Rayner. “It’s a Monday.”)
This is Rayner’s spiritual home. When he was growing up, his father had a little yacht, and he spent his childhood at sea around Auckland’s islands, watching kahawai boil-ups bring in huge flocks of white-fronted terns.
“It’s kind of how I got into seabirds,” he says.
The route was a little circuitous. He failed sixth form twice, left school and went travelling. In Africa, he befriended a couple of master’s students from the University of Cambridge and ended up helping out with their research—one was studying butterflies, the other baboons: “It just lit a fire in me.”
Rayner returned to study at 25, and nine years later, had a PhD on Cook’s petrels. But he likes to be at the frontier of things, and petrels are a bit too trendy now.
Shags, on the other hand, are still deeply unpopular, even in the research world.
“For most people a shag is a shag, but all of our shags are declining, even pied shags—people think they’re really common because they see them behind boats and at the wharf, but they’re all struggling.”
Rayner loves them—especially the spotted variety.
“You wait ’till you see them,” he enthuses. “You don’t think shags are pretty, and then you see a spotted shag—they’re really a pretty bird.”
As we approach Tarahiki, the first sign of the shags’ presence are splashes of white on the cliffs, visible from hundreds of metres away—rivers of guano, streaming like silica down the rock. As we get closer, I can smell them, too: a pungent mix of ammonia and old fish.
The northeastern tip of Tarahiki is pocked with caves, overhangs and arches. Just off the coprosma-clad cliffs, half a dozen sheer-sided greywacke stacks drop into the clear water. Each one is an apartment block, a citadel of shags—birds spaced every half metre, preening in the early spring sun.
They are lovely. Slender, even dainty, their feathers three contrasting tones of grey, their wings speckled with dark iridescent dots. Their feet are bright yellow, and a white stripe like a question mark curls around each eye, which are ringed with turquoise green—the colour of tropical water.
Lovegrove and Rayner start counting. It’s not high-tech, just binoculars and a pencil, and a detailed map of the island. They use the nests as a guide to the number of birds—one nest signifies a breeding pair—and then do a rough check by counting the number of birds on each stack.
“They’re coming and going, it is an approximation,” says Lovegrove. “Like all bird census techniques, it’s a bit of a stab in the dark.”
The nests are messy, guano-stained piles, made of sticks, seaweed, even bits of fishing line and rope. Every now and again, a stick drops into the water—that’s the juveniles, says Rayner, deconstructing their nests in a kind of teenage assertion
It’s as though they’re saying, “I don’t need you any more.”
After an hour or so of counting, Lovegrove is sanguine: “There’s quite a good number of birds.”
Next up are the two smaller colonies on Waiheke. When Rayner and Lovegrove conducted this survey a year earlier, in August 2017, there were no birds on either colony, just empty nests. A camera they placed there revealed the rocks were crawling
Worried it was the beginning of the end for the Waiheke colonies, they stepped up their monitoring, returning every few months across the winter breeding season. Today, we’ll find out if the birds are there—and if they have succeeded in raising any chicks.
“We got guano!” calls Rayner as we get closer. There they are, eight nests on this side of the rock, 12 birds visible. Rayner jumps ashore for a closer look, reporting back that there are chicks in some of the nests.
Presumably the rats are still there, but the birds have managed to protect their eggs this time. Lovegrove isn’t sure what happened last year—perhaps the shags were disturbed by people, or other predators, and nested at the main colony on Tarahiki.
When Lovegrove adds up the numbers, the final tally across all three sites is 552 adult birds and 280 nests. That suggests there are fewer than 300 pairs—a slight decline, but consistent with numbers across the past three years—in a place that used to be home to many thousands.
“We’ve got museum specimens from Tiritiri, Whangaparāoa, Tāwharanui,” says Rayner. “These birds were everywhere.”
Where have all the spotted shags gone? Predation, human disturbance, and fishing practices that cause food shortages could all be factors in their disappearance, says Lovegrove.
The last time the birds nested at Bethells Beach/Te Henga was about 2000, and Lovegrove last spotted them visiting the Manukau—where the birds used to overwinter—in 2008. A friend of Lovegrove’s once found 13 drowned in a set net there: “Perhaps they just couldn’t hack that level of mortality.”
Disappearances don’t usually involve a single culprit. As pressures accumulate, populations become vulnerable to extreme events.
Lovegrove thinks the decline of the spotted shags may tell a larger story about the state of Auckland’s waterways, and particularly the Hauraki Gulf.
Spotted shags feed on small baitfish such as anchovies and pilchards—and those species are now in short supply. Lifelong fisherman Dave Kellian knows more about those little fish than almost anyone. After he saw Lovegrove give a talk on spotted shags, Kellian called him to relate his 40 years of observations.
In the late 1970s, Kellian pioneered the Auckland pilchard fishery.
“Pilchards spawn up in the guts of the Hauraki Gulf in the Firth of Thames—and that’s the home of the spotted shag,” he tells me. “Every pinnacle and rock all the way down on the Coromandel side was just loaded with shags, and they’d go from one side to the other depending on the weather. The population was huge back then.”
Anchovies were plentiful in the gulf then, too, he says.
“Off Waiheke, inside Kawau Bay, it was just black solid in there with anchovy. You could come out of the Mahurangi in, say, July, steam to Whangaparāoa, and when you’d get out to about eight or nine metres, it would be five metres deep with anchovy, and that would go to 20 metres once you got into the deeper water—wall-to-wall anchovies, swimming along with their mouths open, a couple of inches apart.”
The anchovies are gone now, he says.
“There’s still a few, but you would be lucky if it’s three per cent, two per cent of what it was. It’s beyond belief how small that biomass is now.”
The pilchards are pretty much gone, too. In 1995, a mystery virus raced through Australia’s pilchard population, and then New Zealand’s, after an infected container-load of frozen pilchard bait was imported from Western Australia. It was the largest known fish-mortality event in recorded history. Australian scientists described it as a “bushfire-like wave” that spread against the current, moving in disease fronts at a rate of up to 40 kilometres a day.
Kellian is still scarred by the overnight loss of the fishery—the sight of millions of dead pilchards floating on the surface.
“Mate, it was sick. It was a metre deep with dead fish in places, as far as you could steam,” he says. “Halfway from the Mokohinaus to Leigh, for four hours you couldn’t make a bow wave, you were just pushing them apart. People thought it was a bonanza; they were heaped like bloody hay rows along the beach.”
Australia’s pilchard fishery recovered, despite a second disease outbreak in 1998, but Kellian says the Hauraki Gulf pilchards never bounced back to pre-1995 levels. There’s no way to know for sure, because there have never been any fish-stock assessments or biomass estimate studies for pilchards—or anchovies.
A dramatic decline in these two fish species makes life tough for the shags—they have to fly further and work harder to get up to breeding weight.
“The spotted shag is really a barometer to a problem,” says Kellian. “We don’t know what it is, but the shags are telling us there’s something wrong.”
New research by Rayner and scientists at the National Institute of Water and Atmospheric Research (NIWA) supports Kellian’s food-availability theory. The researchers are using chemical isotype studies to track the shags’ changing diets over time—a new kind of analysis that’s only recently become available to ornithologists.
As animals grow, they store tiny amounts of nitrogen and carbon in the tissues of their bodies. (Birds store it in their feathers.) These nitrogen and carbon atoms can contain different numbers of neutrons, and these variations are called isotopes. Depending on where a bird has been and what it has been feeding on, it will store a particular ratio of isotopes in its cells—a kind of molecular diary.
Rayner’s team used NIWA’s mass spectrometry machines to read isotopes in the feathers of spotted shag museum specimens from the Hauraki Gulf dating from the 1880s to the present day.
“It really looks like the diet of these birds has changed in the last 100 years,” says Rayner.
Nitrogen isotopes reveal a bird’s position in the food chain, while carbon isotopes indicate the type of habitat where they’re feeding.
“The composition of their diet has dropped away from being all about fish, and they’ve been starting to eat foods from a lower trophic level, things like squid and crustaceans.
“The carbon isotype signature is also less enriched in the modern birds, and that suggests a major change in their foraging habitat through time. So, something’s going on in the gulf—across the board it certainly seems like there have been changes for the worse.
“The whole ecosystem is echoing that. We’re seeing big declines in red-billed gulls, big declines in white-fronted terns, both of which are fish predators.”
Rayner’s hoping for more funding so that he can track the Tarahiki spotted shags with GPS devices. He wants to get a better idea of where they go when they’re not at the colony.
“I’m really interested to find out what’s going on with these birds and to see if we can arrest the decline.”
The fake shaggery on the Noises is an insurance policy—it won’t address any of the causes of the shags’ decline, but if it succeeds, it will provide another predator-free home for Auckland’s spotted shags.
The two tiny Waiheke colonies could be easily snuffed out by predators or human disturbance, and with Tarahiki the only predator-free breeding site—well, that means we’d be keeping all our shag eggs in one basket.
There are a number of predator-free islands in the gulf, but Rayner and Lovegrove chose the Noises for their experiment because shags once nested there, and because the islands are far enough from Tarahiki to allow the birds to exploit a new area of fish resources, but close enough that they might fly past and spot the colony. Moreover, the island’s guardians embraced the idea wholeheartedly.
When the water taxi brings us ashore at Otata’s stony beach, Sue Neureuter is there in the shallows to greet us: tanned, in her togs, with a bucket full of huge mussels she’s just collected. Sue, Rod and their sister Zoe may be the islands’ owners, but they prefer the term ‘custodians’. The Noises have been in their family for three generations.
The Neureuters are not the rich-listers you might picture when you think of people who own islands. Their father, Brian, inherited the Noises from his aunt, Margaret, and her husband Fred Wainhouse, a retired sea captain who bought the islands in the 1930s, not quite able to imagine landlubber life. The couple spent more and more time there as they became older, living in the tiny bach on Otata, keeping chickens, smoking fish, and brewing their own beer.
“Dad so loved the place,” says Sue. “He used to spend all his summers out here with his aunt and uncle, and when he left school at 15, he took jobs on the boats so he could keep them supplied.”
Sue, Rod and Zoe—now in their 50s—spent their childhood summers on the Noises, and grew up knowing the islands were their responsibility. Their father was conservation-minded before there was a word for it.
“We had a rule—you only ever caught what you could eat on that day,” says Rod. There was no fridge in the bach, so no way to store it. I remember two or three times as a kid catching a little bit too much fish, but we weren’t allowed to leave the table until we’d finished it all.”
As a child, Sue never understood why the family couldn’t live permanently on Otata.
“It was all I wanted to do; I just really marked time until I could be out here. But Dad was a builder in west Auckland. We would have spent more time out here but quite honestly, Dad couldn’t afford to.”
Their parents have passed away, but the Neureuter siblings now spend every summer on the islands with their own children, camping outside the same little bach, which seems like it hasn’t changed much since the 1930s. There’s a long drop, rainwater tank, an outdoor fireplace for cooking, and still no fridge.
But in the clear waters just off the beach, things have changed. Rod used to marvel at his father’s stories—huge hāpuku, snapper a metre long, craypots placed off the beach overnight crawling with a dozen crayfish in the morning.
A generation later, he’s trying to explain to his own kids the abundance he remembers: “The huge work-ups that used to happen just off the main beach, the kahawai bringing the pilchards to the surface, and underneath the kahawai there’d be kingfish—and the gannets going ‘poof, poof’ through the middle of it.”
This is a concept scientists call ‘shifting baselines’—the way large declines in ecosystems over long periods of time are masked because each generation redefines its own earliest memories as ‘natural’.
The Neureuters watched from their beach as scallop dredges carved the seabed, and the number of recreational boats increased every year, as technology made them ever more efficient.
“We’ve lost the majority of the big snapper,” says Rod. “The crayfish is gone from the inner gulf, and every year, you see something else go. Something as basic as a sprat, a yellow-eyed mullet—something everyone has caught off the wharf as a kid—we’ve been here six weeks this summer, snorkelling most days, and I haven’t seen one sprat.
“It’s just gradually got worse and worse, to the point where, as a family, we’ve decided that something needs to be done.”
The siblings want there to be a network of marine protected areas in the gulf, including around parts of the Noises. And they’d like to see the spotted shags back, too.
Sue and Rod remember seeing the birds as children, and Sue shows me multiple references to spotted shags in her mother Marlene’s diaries. “Grey shags,” she called them. “So slim and streamlined compared with the pied shags.”
11 January 1978
Did a few chores, then went round the back of Otata in the big dinghy—saw four grey shags sitting on a rock by the Big Cave. They are so elegant—like city gentlemen in grey suits.
In the 80s or 90s, Sue remembers, the spotted shags disappeared from the Noises. But in December, she was kayaking around the island and one flew right past her: “I was crying, I was so excited.”
She texted Matt Rayner straight away—it was a sign the fake colony may be in the flight path of its targets.
After lunch at the bach, the construction team returns to the fake colony, around the far side of the island, by boat. Sue and I will snorkel around, and we jump in off the beach.
Sue has a vivid memory of the first time she did this, right here, almost 50 years ago. She was six years old. The pebbles glistened and a tiny rock fish darted into view, filling her with amazement—her first glimpse of a different world.
Now, she’s practically a fish herself, swimming with long confident strokes among the kelp gardens. These, too, are diminished, she waves me over to show me a kina barren. Once the large snapper, crays, and other predators go, sea urchin populations explode, then destroy the kelp forests that young fish rely on.
“It’s not meant to be like this,” she says, as we bob above a continuous line of kina curving around the rock. “Look how many there are—nothing can come back while they’re here.”
A rising swell splashes into my snorkel as I follow her around to the shaggery, where Rayner and the others are cementing the last decoy bird in place.
We dry out on the rocks, wondering at the artificial boundaries that humans draw between land and sea.
“What defines an island?” asks Sue. “It’s the water that surrounds it. We’re spending all this effort restoring the island—weed control, keeping out the predators, translocating wētāpunga—but we watch scuba divers comb the water here for crayfish every single day and we can do nothing. We can’t do anything to protect the ocean, because we have laws that are not holistic.”
That reflects New Zealand’s historic attitude towards the sea, says Rayner.
“We still have this colonial mentality where we think it’s a place where we can do whatever we want.”
New science is revealing that the connections between marine and terrestrial ecosystems are much richer than anyone thought—and seabirds are the vital link in the chain. It’s long been known that seabirds transport ocean nutrients ashore, but recent research is showing that the enrichment cuts both ways.
One ground-breaking study on Palmyra Atoll in the central Pacific Ocean found that seabirds roosting on native trees fertilise soils, which in turn boosts nutrients in coastal waters. Those nutrients increase the abundance of plankton, which then attract manta rays to native-forest coastlines.
Another study, conducted on the Chagos Archipelago in the Indian Ocean, found that coral reefs near rat-infested islands—where seabird populations had plummeted—had fewer nutrients and fewer fish grazing on the algae that compete with corals. Around rat-free islands, fish grew faster, and the total biomass of reef fish was almost 50 per cent higher.
Similar research by PhD student Lyndsay Rankin on New Zealand’s Mercury Islands, off the east coast of the Coromandel, has shown that predator-free islands with healthy seabird communities have much higher seaweed diversity in their surrounding reefs than islands where rats have only just been eradicated.
Spotted shags move between those interwoven worlds of land and sea more freely than we can ever hope to do. If we’re listening, their decline tells more than a tragic story of one species, shot for sport by ignorant fishermen. It’s a message from that other world, just beneath our sandy feet, that all is not well.