The raucous squawking of the forest's most rambunctious inhabitant is coming from an unexpected place. The kaka – a rowdy native parrot that is rarely seen in the wild in New Zealand – has perched on the roof of the old postmaster's house.
It's such birds that visitors take the water taxi over to Ulva Island to see. Ulva is one of the most remarkable wildlife sanctuaries on earth, with introduced predators having been eradicated in 1997. This makes it a safe breeding ground for species such as the weka, saddleback and Stewart Island robin that have all but died out elsewhere.
The red-roofed postmaster's house has a part to play in this. Established in 1872, the post office was Stewart Island's first. The 267-hectare Ulva Island was visible to the fishermen and sawmillers who had camps around Paterson Inlet. When the irregular ships from Scotland arrived bringing mail, postmaster Charles Traill would climb up to the top of what became Flagstaff Hill and raise a flag to alert them.
Aside from people rowing over to collect letters, Traill mostly had the island to himself. A keen naturalist, he put in a garden but left the bulk of the island intact. While he was postmaster, the Tourist Department put down a few walking tracks. Then, in 1899, the island was set aside as a nature reserve. It has a remarkably long, unbroken history of conservation.
Ulva Island is part of the Rakiura National Park, which makes up about 85 per cent of Stewart Island. Aside from the odd track, most of it is podocarp forest. Some introduced species, such as rats, feral cats, deer and rabbits, made it over to this often-forgotten, wind-blown add-on at the very bottom of New Zealand. Crucially, however, the mustelid family – the stoats, weasels and ferrets that devastated native species on "the mainland" never settled in. This has blessed the National Parkwith native wildlife – it's pretty much the only place on earth where you have a chance of seeing a kiwi during daylight hours.
But human settlement – or, rather, its repeated attempts – has played a part. There is evidence that the Maori arrived on Stewart Island in the 13th century, but they have only inhabited it sporadically and in low numbers. Small islets are still reserved for traditional muttonbirding. Local Rakiura Maori sail over at set times of the year to harvest shearwaters.
There are over 100 archaeological sites relating to Stewart Island's Maori heritage, most of them small middens and burial sites on the sheltered eastern side. Many are around The Neck, the narrow spit guarding the entrance to Paterson Inlet, and parts of the island that aren't part of the National Park are managed by the Rakiura Maori Land Trust.
The Rakiura Museum in Oban, Stewart Island's only village, focuses on European history. The display cases are filled with remnants of industries that have floundered here over the years. First to arrive were the sealers in the early 19th century. After stocks ran low, whalers replaced the sealers.
The current population of Stewart Island is just under 400 and has never been much higher. One settlement scheme was at Port William, on the northern coast. Now part of the National Park, it's the starting point for Ruggedy Range's guided day hike along the forest and coast. The walk is largely focused on nature, but owner-guide Furhana Ahmad diverts when there's a interesting-enough trace of human heritage.
"In 1864, the Crown bought Stewart Island from the Maori for £6000 – then a lot of money and the highest price paid anywhere in New Zealand," says Furhana outside the Department of Conservation hut that provides basic overnight accommodation for walkers. "So they tried to recoup some of that by earmarking settlements around the coast."
At Port William, where the hut now stands, a small group from the Shetland Islands in Scotland was lured over to make a home. The report they were given of the prospects there was optimistic, to say the least.
"In Scotland, they were used to long line fishing," says Furhana. "They would leave the lines out, and come back later. When they tried that here, seals ate the fish they'd caught."
The Shetlanders had arrived in time for a particularly harsh winter. Within 15 months, they had given up. The gum trees they planted by the waterfront are the only physical reminder they were there.
Along muddy trails and creaking trees , the trek heads uphill to emerge at a clearing where a couple of old, rusty log haulers stand.
The machines were left behind when yet another industry – timber – dwindled to a halt. Unable to compete with South Island operations, conservationist restrictions were put in place before any large swathes of native forest could be cut down.
At the beach in what's left of the sawmill, the steam engine and boilerhouse are coating with orange oxide. Tramlines are almost entirely consumed by the undergrowth.
Back in Oban, near a church and the jetty, the South Sea Hotel attracts a curious mix of hikers and local fishermen. Yet the air is awash with the sounds of bellbirds and tui. Kiwis are occasionally found scuttling in the bush behind the rugby pitch, and unceasingly noisy kakas strut along waterside benches. Man has a footprint on Stewart Island, but the kakas know they're in charge.
Virgin Australia, codesharing with Air New Zealand, fly to Wellington, with connections to Invercargill. Stewart Island Flights offer a seasickness-free prop plane hop from Invercargill to Stewart Island. See virginaustralia.com, airnewzealand.com.au, stewartislandflights.com.
The Observation Rock Lodge has prime hilltop-views, and plenty of birdlife enjoying the gardens. Rooms cost from $NZ195. See observationrocklodge.co.nz.
The full day Coastal Highlights guided walk through the Rakiura National Park with Ruggedy Range costs $NZ230 per person. See ruggedyrange.com.
Stewart Island Experience runs a 90 minute Village and Bays tour around many of the heritage sites for $NZ45. See stewartislandexperience.co.nz.
The South Sea Hotel is one of New Zealand's classic pubs, and serves up good quality local mussels and blue cod. See stewart-island.co.nz.