Our Changing World

Thursday 26 March 2015, with Alison Ballance, Ruth Beran & Veronika Meduna

On This Programme

Black Petrels - New Zealand's Most At-Risk Seabird

By Alison Ballance

“The clackers stand outside their burrows and call at the top of their lungs trying to attract a female in. They’re single males, so they’re trying to attract a new girlfriend.  At the moment we call them the ‘Desperate Dans’, because it’s near the end of the [breeding] season and they’re still trying to get a girlfriend.” Seabird researcher Biz (Elizabeth) Bell.

A black petrel incubating an egg, in a nest chamber it has excavated under a large puriri tree at Glenfern Sanctuary

A black petrel incubating an egg, in a nest chamber it has excavated under a large puriri tree at Glenfern Sanctuary

Photo: Scott Sambell / Glenfern Sanctuary

Biz (Elizabeth) Bell has studied black petrels for 19 years, and hasn't lost her enthusiasm for what she calls "magic birds". The bird she is holding is marked with a stripe of white twink on its head.

Biz (Elizabeth) Bell has studied black petrels for 19 years, and hasn't lost her enthusiasm for what she calls "magic birds". The bird she is holding is marked with a stripe of white twink on its head.

Photo: RNZ / Alison Ballance

Black petrels (which are also called Parkinson’s petrels) are a familiar seabird sight in the outer Hauraki Gulf. But although they’re a very visible bird, they‘re listed as nationally vulnerable, and are recognised as being the seabird most at risk from commercial fishing. There are just 2500 breeding pairs of black petrels, and their total population, according to Biz Bell from Wildlife Management International, is somewhere between 11,000 and 21,000 birds. Biz says the population most likely numbers about 15,000, which includes young birds and non-breeders (black petrels don’t usually begin breeding until they are 4-5 years old).

The single ‘clacking’ males begin their efforts to attract a mate in October, and they may carry on through until the end of February. During that time they call every night for most of the might. They have cleaned out a nesting burrow, which is excavated underground amongst the roots of trees, which they hope will meet the approval of a female attracted by the sound of their clacking.

In late summer, the other night-time sounds on the high slopes of Great Barrier Island’s Hirakimata/Mount Hobson, according to Biz, are “lovers. A male has managed to get hold of a female, and they’re canoodling n the burrow, basically, getting to know each other, pair-bonding and getting ready to pair up the following year to breed.”

Meantime, early February is also when this year’s black petrel chicks are just starting to hatch. With so much black petrel activity happening, February is a key time of the year for Biz Bell, who visits the black petrel colony for up to three weeks to monitor hatching success in the 427 study burrows, look for new burrows and band any unbanded birds.

View from the largest black petrel colony on Hirakimata/Mount Hobson on Great Barrier Island across to Hauturu/Little Barrier Island which is home to a very small colony of black petrels.

View from the largest black petrel colony on Hirakimata/Mount Hobson on Great Barrier Island across to Hauturu/Little Barrier Island which is home to a very small colony of black petrels.

Photo: RNZ / Alison Ballance

A black petrel chick that is just a few days out looks out through the researcher's access into its underground burrow. It will take 2 months from hatching before it flies away to sea.

A black petrel chick that is just a few days out looks out through the researcher's access into its underground burrow. It will take 2 months from hatching before it flies away to sea.

Photo: RNZ / Alison Ballance

Biz has been studying the birds since 1995, and the annual February trip is one of three trips she makes to the colonies on Great Barrier Island and Hauturu/Little Barrier Island each year. In those 19 years she has banded more than 2000 adult birds, and 2500 chicks. Only 204 of those banded chicks have returned to the colony, and Biz says this low survival rate of less than 10% does not bode well for the future of the species and is something they are working to change.

Although rats and feral cats predate on chicks and adult birds on land, the main threat to black petrels comes from both commercial and recreational fishers in the outer Hauraki Gulf, which is a key feeding area for the birds when they are feeding chicks. The petrels are an accidental by-catch, which are attracted by bait and become hooked on fishing lines.

“Unfortunately the population is showing a slight decline. [But] we’re hoping we can change that around and as more people understand the risks to these birds we can help mitigate those risks.”

Biz is working with the Southern Seabird Solutions Trust, which is working with commercial fishers to find ways of preventing black petrels getting caught on fishing lines. Each year Biz hosts a number of fishers at the Mount Hobson research site, introducing them to the birds on land, and getting them used to gently handling birds, in case they need to remove birds from fishing gear at sea.

Black petrels, with a wing span of about 1.1 metres, breed in underground burrows; they lay a single egg, which is visible here through a researcher's nest access tunnel, which is usually covered with a lid.

Black petrels, with a wing span of about 1.1 metres, breed in underground burrows; they lay a single egg, which is visible here through a researcher's nest access tunnel, which is usually covered with a lid.

Photo: RNZ / Alison Ballance

Once common all over the North Island and the top of the South Island, the stronghold for black petrels today is Mount Hobson on Great Barrier Island, with a small population on Hauturu/Little Barrier Island, and a few birds breeding in sanctuaries such as Windy Hill and Glenfern on Great Barrier Island.

The largest colony of black petrels, numbering about 2500 breeding pairs, is found on the high forested slopes of Great Barrier Island's highest point, Hirakimata/Mount Hobson

The largest colony of black petrels, numbering about 2500 breeding pairs, is found on the high forested slopes of Great Barrier Island's highest point, Hirakimata/Mount Hobson

Photo: RNZ / Alison Ballance

Black petrels are long-lived – there are birds that were banded more than 30 years ago that are still breeding in the colony – and Biz says this reinforces the fact that to fully understand a species you need to study it for at least the duration of its life.

Luckily for the birds, even after 19 years, Biz is as enthusiastic as ever about black petrels.

“These birds are magic," says Biz. "Season 19, and I’ll keep doing it to 90 if I can. These birds are just incredible.”

You can find more stories about New Zealand seabirds in the Our Changing World bird collection.

According to the MPI web site ‘the National Plan of Action - Seabirds 2013 recognises New Zealand’s unique place in the world for seabirds and our desire to be at the leading edge of international seabird conservation.’

In a recent Our Changing World interview, Edward Abraham and Finlay Macdonald from Dragonfly Science talked with Alison Ballance about Analysing Seabird By-Catch in Fisheries and discussed how a recent analysis has highlighted a significant problem with by-catch of Parkinson’s black petrels in the Hauraki Gulf snapper fishery.

Analysing Seabird By-Catch in Fisheries ( 14 min 37 sec )

Boardwalked tracks on Great Barrier Island's Mount Hobson are to protect black petrel burrows from damage. Biz Bell and Katherine Clements hold a parent black petrel and its chick

Boardwalked tracks on Great Barrier Island's Mount Hobson are to protect black petrel burrows from damage. Biz Bell and Katherine Clements hold a parent black petrel and its chick

Photo: RNZ / Alison Ballance

You'll find the audio links for the story 'Black petrels - New Zealand's most at-risk seabird' below:


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Volunteering for Conservation

by Veronika Meduna

Katherine Clements recently completed a neurobiology degree at Harvard University, but decided that she wanted to spend a year as a volunteer with the Department of Conservation, studying seabirds.

Katherine Clements recently completed a neurobiology degree at Harvard University, but decided that she wanted to spend a year as a volunteer with the Department of Conservation, studying seabirds.

Photo: RNZ / Veronika Meduna

Katherine Clements recently completed a neurobiology degree at Harvard University, but then decided that she wanted to spend a year as a volunteer with the Department of Conservation, studying seabirds.

“I actually had a job lined up back in Boston to continue doing neuroscience research. I was going down this track into medicine and research but I really wanted to do something different before I committed myself to such a long haul.”

Having grown up in a small town on the Atlantic coast, Katherine was interested in seabirds. She applied for a travelling fellowship and when a selection committee member asked her what she would do if she could travel anywhere for ten months, she simply said she wanted to “migrate with the albatross”.

Last month, she joined the field team during the black petrel survey on Great Barrier Island. “Black petrels are the most at-risk seabird in New Zealand, predominantly due to fishery bycatch. As a result, it’s really important to monitor their populations and better understand their foraging distribution so that measures can be undertaken to minimize the interactions between fishing vessels and the birds.”

Katherine says she has combined fieldwork with office-based research, and has enjoyed her policy related work. “One of the biggest projects I’ve been working on is the development of a seabird framework. The hope is to bring together all relevant seabird research into a single database, so that we can easily identify where gaps in knowledge exist.”

Find out more about opportunities to volunteer for DOC.


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World's only glowing freshwater limpet

The shell of luminescent limpets is paua-shaped and thicker than that of other freshwater limpets found in New Zealand.

The shell of luminescent limpets is paua-shaped and thicker than that of other freshwater limpets found in New Zealand.

Photo: Landcare Research

Luminescent limpets like stony streams and are found in most parts of the North Island, but not in the South Island.

Luminescent limpets like stony streams and are found in most parts of the North Island, but not in the South Island.

Photo: Siouxsie Wiles

by Veronika Meduna

New Zealand is known for its extraordinary flora and fauna, which includes many species that are found nowhere else. One of our lesser known endemic animals is a tiny glowing limpet that lives only in stony streams throughout the North Island.

These luminescent limpets belong to the genus Latia, and they are the world’s only freshwater species capable of producing a brightly glowing slime. The limpets release the slime only when they are disturbed, and University of Auckland microbiologist and bioluminescence enthusiast Siouxsie Wiles thinks they use it mostly as a defense mechanism to startle or distract predators. She says it is also possible that some of the glowing slime sticks to the predator and makes it more at risk of being eaten itself.

Latia limpets are related to land snails and have evolved a limpet-like shell shape to cope with flowing waters. They are abundant in gently flowing stony-bottom streams in most parts of the North Island, where they graze on algae that grow on rock surfaces, and they are most common in streams with good water quality, which makes them a useful environmental indicator species.

The public will get a chance to see glowing limpets during night tours, guided by Project Twin Streams community coordinator Derek March, at this year’s EcoWest Festival which runs until April 12.


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Starting to Gel: A Tough, Stretchy, Mouldable New Material

by Ruth Beran

A photo of the helicopter, and the tough gel balls before being thrown out the window

From left to right: the helicopter, and the tough gel balls before being thrown out the window

Photo: Moratti and Hanton Research group

Chemists don’t usually drop balls from helicopters flying at 1200 feet, but Prof Lyall Hanton and his team from the University of Otago wanted to test a new material they have created by throwing it out the window.

A photo of Shailesh Goswami holding a ball made of the tough gel that will be thrown from the helicopter

Shailesh Goswami holding a ball made of the tough gel that will be thrown from the helicopter

Photo: Moratti and Hanton Research group

The material they were testing is a gel, made mostly of water.  The balls, which could fit in the palm of your hand, not only survived the fall from the helicopter intact they also bounced when they hit the ground.

It’s a sign of how tough these gels are.

"From what we know…this will be the strongest gel reported,” says Lyall.

The gel is also incredibly stretchy, stretching at least 40 times, and will still bounce back to its original size after being compressed 99%.

There are advantages to having a strong, tough, stretchy gel. For example, it could be used to release a drug in the body. Unlike ordinary jelly which would just break up and be moved around the body, you could put it under the skin and “it’s going to stay there, and you know it’s going to stay there,” says Lyall.

The gel consists of 85% water, plus a monomer and a crosslinker. In the gel, the monomers form polymers, and the crosslinker binds the ends of these extremely long polymer chains in a three dimensional network. The gels are cross-linked in such a way that the long, linked polymer chains can be stretched much more than short chains, resulting in the strong, stretchable gel.

A photo of Lyall Hanton, Shailesh Goswami and John McAdam

From left to right: Lyall Hanton, Shailesh Goswami and John McAdam

Photo: RNZ / Ruth Beran

When asked what the monomer consists of, John McAdam says:

“That’s a secret. We’re not going to tell you what the secret ingredients are.” Shailesh Goswami adds: “Because we want to publish this work in some good journal and the chemistry world is a very, very cruel world.”

An initiator and a promoter is also needed to initiate the reaction and promote the cross linking process, and by weight only 15% of the gel is made up of the chemical ingredients, the rest is water.

This makes for a very cheap product. The monomer is $1 per kilo and the crosslinker is around $2 to $3 per kilo.

The gel then needs to be cured, either slowly at room temperature or in the oven at 30˚C for two hours.

The team are already thinking of possible applications such as soft bandages, a high-tech shoe pad for running shoes or for use in a gel actuator. The material is easily mouldable.

Listen to a previous story on gel actuators here.

Polymer Gel Actuators ( 12 min 37 sec )

However, given that the gel is mostly water, long term applications would require the gel to be in an environment away from air. “In time, the gel will dry out so the applications we would use this for would need to be ideally in closed ones” says Lyall.


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'Team Rat' Completes World's Largest Island Eradication

By Alison Ballance

The world’s largest island rat eradication has just been completed, with the final load of rat bait dropped on subantarctic South Georgia Island from a helicopter flown by New Zealand pilot Peter Garden, using a specialised bait spreader developed and made in New Zealand. That the operation was possible at all was the result of 50 years of techniques and experience developed on New Zealand islands.

The very last bag of rat bait is loaded into the spreader bucket under Peter Garden’s helicopter Alpha Mike, at 12.37pm on 23rd March 2015

The very last bag of rat bait is loaded into the spreader bucket under Peter Garden’s helicopter Alpha Mike, at 12.37pm on 23rd March 2015

Photo: South Georgia Heritage Trust


The South Georgia rat eradication, which has been carried out by the South Georgia Heritage Trust’s ‘Heritage Restoration Project’, is nearly eight times larger than the previous largest island eradication on Australia’s Macquarie Island. University of Auckland biologist and eradication expert James Russell says it is globally significant.

“They didn’t just do an incremental change – they did a step change. They moved from 11,000 hectare Campbell Island and 13,000 hectare Macquarie Island, they just grabbed the bull by the horns and went for it.”

It all began in 1964, when the late Don Merton and fellow conservationists declared that they had got rid of Norway rats on tiny Maria Island, in the Hauraki Gulf. At that time just 0.5 per cent of New Zealand islands were free of mammalian pests; today, 10 per cent are pest-free. Following Maria Island, conservationists began to tackle larger and larger islands, such as 170 hectare Breaksea Island in Fiordland and then 2000 hectare Kapiti Island.

The rat eradication on South Georgia Island uses a bait containing an anticoagulant poison.

The rat eradication on South Georgia Island uses a bait containing an anticoagulant poison.

Photo: South Georgia Heritage Trust

When Norway rats were eradicated from remote subantarctic 11,300 hectare Campbell Island in 2001, it was a monumental conservation achievement that suddenly opened up the possibility of restoring large islands around the world. The Campbell Island rat eradication, led by Peter McClelland, managed to overcome the obstacles of distance (700 km from mainland New Zealand) and ferocious subantarctic weather by using a team of five helicopters that used specialised bait-spreading buckets and GPS to spread baits containing the rodenticide Brodifacoum across the entire island, including the steep cliffs, ensuring that every rat on the island had access to the anticoagulant poison.

South Georgia Island is a British Territory that lies at 54°S, off the southern tip of South America, near the Falkland Islands. The island is 375,00 hectares in size. The area of the island from which rats had to be removed is 100,000 hectares in size, so large that the rat eradication had to take place in three stages over five years. The eradication has been a race against time, to get it completed before global warming melts the large glaciers that effectively divide the island into a number of ice-free valleys. Research into the genetics of rats living in different valleys, carried out by Bruce Robertson and Neil Gemmell from the University of Otago, confirmed that they were all distinct populations. This meant these ice-free areas could then be treated as ‘eradication units’, and this allowed the eradication to be done as a ‘rolling front’. Bait was dropped in a few eradication units in a trial carried out in 2011, a much larger number of units treated two years later, and the third and final bait drop treating the remaining ice-free valleys in February and March 2015.

The South Georgia Island rat eradication team leader, Tony Martin, reported in the late March issue of the Newsletter of the South Georgia Habitat Restoration Project, that Kiwi pilot Peter Garden, aided by two other New Zealand helicopter pilots, finished dropping the final bucket-load of bait on South Georgia just after midday on 23 March 2015.

Peter Garden has made significant contributions to many island eradications, beginning with Campbell Island. Eradication expert Peter McClelland says Peter Garden is highly respected.

“He’s certainly one of the top eradication pilots in the world. Both his flying skills, and also the work he puts in planning and preparing for these operations.”

Chief pilot Peter Garden flying on South Georgia Island, with Nordenskjöld Glacier in the background.

Chief pilot Peter Garden flying on South Georgia Island, with Nordenskjöld Glacier in the background.

Photo: South Georgia Heritage Trust

It will be two years before the valleys treated with bait this year can be checked to confirm whether or not the eradication has been a success, but there are signs that areas treated in 2011 are now rat-free, with the first confirmed nest of the threatened South Georgia pipit found in January 2015.

The next job of Team Rat, as they call themselves, is to head to the valleys treated in 2013, to see if any of the rat detection devices left there last summer give any indication of the presence of mice.

The idea of a rolling front was developed on Ulva Island in the 1990s and, according to James Russell, that technique is really important, “as it’s going to be the kind of approach that will be required to treat larger islands in future, and perhaps even scale up to a predator-free New Zealand.”

South Georgia Island is 170 kilometres long, between 2 and 40 kilometres wide, and rises to 2,934 metres at its highest. About three quarters of the island is covered in glaciers and snow fields, and apart from a brief snow-free summer period, it is usually covered in snow to sea level. At latitude 54°S, South Georgia is further south than New Zealand’s Campbell Island (52°S). The island is now uninhabited, about from two British Antarctic survey bases, but at the height of the whaling boom it was home to about 2000 people.

The South Georgia Habitat Restoration programme has been organised by the South Georgia Heritage Trust which raised more than £7.5 million.

The New Zealand Department of Conservation, meanwhile, is planning its next subantarctic island eradications. Eradication manager Stephen Horn says "the main Auckland Island (with mice, cats and pigs) and Antipodes Island (mice) are the only two island groups remaining in the New Zealand Subantarctic with introduced mammalian pest species."

"The Antipodes Island Mouse Eradication, planned for winter in 2016, is the next step towards a long term goal of a pest-free New Zealand subantarctic region," says Stephen. "The Antipodes project follows on from successes on Campbell Island - rats in 2001- and Enderby island - mice and rabbits in 1993 - with experience and expertise gained on these eradications helping to shape the strategy and identify the risks on Antipodes. The sites are of huge biodiversity value and a one-off eradication operation leaves a legacy of recovery and preservation for incredibly valuable ecosystems. The subantarctic region also has low risk of a return on mammalian pest species, so eradication is the single most effective conservation strategy for these situations."

Alison Ballance joined a Department of Conservation expedition to Antipodes Island in 2014, carrying out pre-eradication monitoring and fixing the island hut which was damaged by a slip early in 2014.

Expedition to Subantarctic Antipodes Island ( 36 min 53 sec )

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Coming Up On Our Changing World on 2 April

Feeding the birds – and what impact it has on the birds in your back garden, we watch as a participant is tested for variation in blood pressure and we meet scientists who use microscopic fossils to study the past.