Hypothetical: you're a keen naturalist, and you want to get into North Korea to assess the habitat available for migratory birds. What do you do?
Well, you could just ask to visit. And that's exactly what the Pukorokoro Miranda Naturalist Trust members did back in 2007.
There's not a lot of chemicals used, because there's bans on importing and the West isn't supplying fertilisers ... it's probably the biggest organic farm in the world.
The status of the Korean shoreline was a glaring gap in ornithological knowledge, one that the New Zealanders felt well-placed to fill.
For years, the Pukorokoro Trust had been working just over the Chinese border with locals and officials.
They had decades of experience tracking, surveying and assessing habitat around the shorebirds' migratory path, East Asian Australasian flyway.
And fortunately, they were from New Zealand.
'New Zealand is not seen as much of a threat to anyone,' says Adrian Riegen, a builder from Auckland who has devoted much of his life to shorebird conservation and the trust.
Shorebirds dart backwards and forward on the water's edge, and though some breed on the shorelines of Australasia, many migrate north to take advantage of the insect boom of the Arctic summer.
They are birds without borders. They don't recognise the solid lines on a map that stop humans from passing. Instead they look for places to land, to feed and rest.
The East Asian Australasian Flyway is a kidney-shaped conduit that conveys birds between Australasia and the Arctic each year.
Fifty million birds use it annually, and eight million of them are shorebirds.
Intertidal habitat along the East Asian Australasian Flyway is disappearing at an astounding rate, and this has translated into catastrophic drops in the populations of many flyway species.
After studying satellite images of the edges of the Yellow Sea, Riegen and his colleagues had a hunch: North Korea might still have places for the birds.
In 2009, a delegation from the trust visited North Korea for the first time. While there, they made contact with an organisation called the Nature Conservation Union of Korea.
The union, Riegen says, is incredibly keen to further their understanding of shorebirds.
Since then, the trust has been surveying what happens to shorebirds while they're within North Korean borders—which was more difficult than you'd think.
'A lot of it was bouncing around on rather ill-formed roads in the back of a mini bus getting from one place to another,' says David Melville, an ecologist and member of the trust.
'There is no coast road where you can just drive along from one site to the other.'
Riegen says they often had to travel 20 or 30 kilometres inland along dirt roads. 'If it's been raining, they're almost impassable,' he says.
'When we did get down to the coast though, we were visiting areas which include salt ponds,' Melville says.
'There's a lot of rice paddy along the coastline as well, and then extensive intertidal flats down at the shore.
'This year, we've identified several sites of international importance for the bar-tailed godwit, for the far eastern curlew, which as endangered species, and also for the Eurasian curlew.
'Last year we sound several sites for great knots, which is another endangered species.'
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A site is classified as of international significance if it regularly supports one per cent or more of a whole population of a species.
'What we've seen is certainly looks a lot healthier than what we've seen in China and South Korea, because there's far less development of the coast,' Riegen says.
'There are sea walls along it and there is some reclamation, but a lot of it has ground to a halt because of lack of money or equipment to do it.
'There's also far less industrial pollution, because there's far less industry along these rivers.'
Most of the western coastal strip of North Korea, Riegen says, is farmland.
'There's not a lot of chemicals used, because there's bans on importing and the West isn't supplying fertilisers. So it's a lot of manual labour to keep it,' he says.
'It's probably the biggest organic farm in the world.
'Obviously we can't tell without doing some science, but it certainly looks pretty healthy, and there's not a huge amount of pressure on these birds, from what we can see.'
This stands in marked contrast to almost every Chinese and South Korean site, which even if marked as a reserve site is unlikely to be completely free of development, pollution, weeds or disturbance.
For Riegen, the ecological importance of North Korea is not given appropriate international recognition.
'For me, North Korea is the safety valve on the whole flyway,' he says.
'We're have lost so much habitat along the Chinese coast and the South Korean Coast, but at the moment substantial parts of the North Korean coast remain largely undeveloped.'
Melville agrees: 'As we lose habitat elsewhere, the birds are going to be pushed more and more into remaining habitats, which I think, by default, means North Korea.'