Thousands of birds perished in the black tide that followed the MV Rena's grounding. A year and a half on, Bay of Plenty reporter Jamie Morton checks on the recovery of the disaster's forgotten victims.
A light shines through the darkness, dancing over rocks a few metres from the night tide gushing against Moturiki Island.
It probes narrow crevices, boulders, leaf-strewn banks sheltered by pohutukawa trees, deep holes burrowed beneath walking tracks.
Some nights, Karin Sievwright's headlamp finds its tiny target - a feathered white belly and two little eyes that glow in the gloom.
The island, a rocky, scrub-covered hump that extends a few hundred metres off Mt Maunganui's main beach, is most famous for the blow- hole at its seaward end. It is also home to around 200 little blue penguins.
Hundreds more are tucked away within a short walk from here.
They shelter in hovels below the walkway that rings Mauao, around the shores of nearby Rabbit Island.
The street lights along Marine Parade twinkle as Ms Sievwright crouches beside a burrow running directly beneath the footpath at Moturiki Island.
A few grey feathers left behind tell her the hole afforded a cosy home to a few penguins not too long ago.
The young Massey University student makes her way around the western side of the island, pulling herself over and between rocks, hoping to find the source of the cries she'd heard earlier in the evening.
She carries a remote sensor that can tell her the difference between one of 350 penguins that had been rehabilitated in the Rena disaster, or one of roughly the same number that hadn't needed to be.
Sometimes she only needs to kneel down beside a burrow, reach inside with the sensor, and wait for a beep.
But on this cool April night, there is no sign of any penguins. Perhaps it's a little too early in the season.
Wait a few more months, she says, and you'll find dozens around the rocks at night, when the hardy little creatures come out to play.
Ms Sievwright wasn't working with the birds when the oil hit her home city, but was still around to witness the mess.
"It's pretty crazy, to think what happened."
Flash-back to 2.14am, October 5, 2011.
The fully laden MV Rena, carrying 1700 tonnes of heavy fuel oil, met the Astrolabe Reef at full speed.
By lunch time, Massey University wildlife veterinarian Helen McConnell and some of her team were in Tauranga.
Before the environmental consequences of the grounding could be realised oil-covered corpses of a few dead seabirds washed up on the beaches, a taste of what was to come.
That weekend, stormy seas sent 350 tonnes of oil into the ocean, blackening the rocks and shores around key habitats.
For the Bay of Plenty's little blue penguin population, just starting their breeding season, the oil couldn't have arrived at a worse time.
Wildlife responders opted to save the adult birds and take them to a recovery facility rapidly set up in an empty field at Te Maunga, in industrial Mt Maunganui. In many cases, this meant sacrificing un-weaned chicks, who died from starvation without their parents, and eggs that would never hatch.
Many penguins and scores more petrels and shearwaters froze to death when oil blocked their ability to insulate themselves against cold.
Of more than 2000 dead birds collected, more than half had been tarnished with oil. Of the 383 oiled penguins retrieved, 18 didn't survive through cleaning and treatment. Some had to be euthanased, a handful dying before they could recover.
A further 89 oiled penguins were found dead in the wild, around a quarter of them drenched in the tar-like muck.
Experts were also forced to make a heart-breaking decision over how to save the region's small population of tiny, endangered New Zealand dotterels. Sixty were taken into captivity, six dying because of continuous stress.
By November, the Oiled Wildlife Facility had become a tented village, complete with a washing facility housed in a shipping container, a morgue and reticulated pools.
More than 400 birds - including a handful of pied shags and many penguins - spent the summer here, one vet likening their experience to an alien abduction.
Penguins, which soon grew lesions on their feet from standing for too long, were taken from purpose-built cages and put into pools for hours, forcing them to swim and rebuild their strength for their return to the wild.
By March last year, all of the captive birds were released again - the penguins waddling disorientedly back to freshly cleaned breeding grounds.
"We had a release rate of around 95 per cent, which by international standards was really good," Ms McConnell said. "Most people say that if you can get over 90 per cent of the birds out, you are doing well, and I think with the 95 per cent, we were pretty pleased."
There were hopes the birds would get back to business in their natural habitats, but worries remained.
Lee Barry, terrestrial conservation manager at WWF New Zealand, said their ordeal up to that point had only been half the story.
"Finding out if they have survived, and if they are still healthy and breeding is critical to determining the ongoing impact of New Zealand's worst maritime environmental disaster."
Of $60,000 raised by WWF's Bay of Plenty appeal, $20,000 was granted to Massey University's veterinary school, Wildbase, for monitoring.
Rena Recovery, a special initiative set up by authorities, was also funding a $252,000 wildlife programme over three years, implemented by the Department of Conservation.
With the penguins' second post-Rena breeding season approaching, things appear promising.
Ms Sievwright, whose work on the project is contributing to her thesis, is one of a dozen people in the Bay of Plenty who take turns heading out at nights.
"For every penguin we'll come across, we'll scan them and individually ID them all, so we can say this was an oiled bird that came from Te Maunga," she said. "And we've also got a big control group, about 370, which was a similar number that were in the area but not directly affected by the oil, so that gives us a comparison."
Encouragingly, those penguins taken into captivity had laid around the same amount as those left. The birds are also regularly weighed - those with a higher mass considered more likely to survive in the wild.
"We try not to disturb them ... we just want to see how many eggs they're laying, following the chicks, that sort of thing," she said.
"We've definitely had some positive signs and it's good to see they are breeding and actually making an effort - they're laying eggs, producing chicks, and most of those chicks are surviving to fledge."
Eighty-three clutches were monitored in the first breeding season, and nearly all of the rehabilitated birds laid their normal number of around two eggs.
"But we are going to monitor their second breeding season as well, just to see if there aren't any longer-term effects.
"They are pretty robust and pretty tolerant to the stress, which I think is what helps them in some ways, especially coping in captivity."
Despite the death it dealt, the Rena ordeal had provided a deeper insight into little blue penguins in the Bay of Plenty, of which there had been few scientific studies.
Ms Sievwright's research may ultimately be published in an international peer-reviewed scientific journal.
"It's definitely helping us understand the local population a lot more, and I guess it's just a little bit of a shame that it takes such a disaster like this to really come to terms with what we've got in our own backyard," Ms McConnell said.
Locals had been left surprised at just how many penguins shared their shore.
The monitoring programme is expected to last at least another year, with surveyors checking to see egg numbers did not drop off.
"Overall, it was a challenging response, but I think the team that worked on it are pleased with the outcome so far," Ms McConnell said. "And in a couple of years' time, after the monitoring, we'll hopefully be able to round off the story and truly know how successful it all was."
140 National Oiled Wildlife Response Team personnel involved following the disaster, including veterinarians, expert responders and ornithologists.
383 little blue penguins recovered, of which 365 survived to be re-released.
60 endangered New Zealand dotterel recovered, of which 54 survived to be re-released.
89 dead little blue penguins found.
2083 total dead birds collected, of which 1379 were oiled.
$252k Rena Recovery funding for three-year wildlife monitoring programme. WWF raised another $60,000 in a Bay of Plenty appeal.
350 tonnes of heavy fuel oil spilled into the ocean.
Little Blue Penguins
Hundreds of little blue penguins live and breed around the Bay of Plenty coastline.
Several hundred are thought to have died in the Rena disaster; wildlife workers recovered the oiled bodies of 89.
Of the 383 taken into captivity, 18 died - some having to be euthanased.
Many chicks and eggs were sacrificed as adults were rescued to one day breed again.
Of the 365 released back into the wild, monitoring has found they are breeding and laying as many eggs as those which were left in their habitats - an encouraging sign.
New Zealand Dotterel
The Rena disaster is responsible for the deaths of a handful of endangered dotterel; six died in captivity, and a few more died following release.
A total of 60 were rescued from the path of oil soon after the grounding, and monitoring had found most of these had since survived and were breeding again.
The tiny, sensitive shorebirds number only around 2100 in New Zealand, and around 150 in the Bay of Plenty.
Two were found oiled during the disaster, but none were found among dead seabirds that washed up on beaches.