Stewart Island is both a land apart and a rather poignant reminder of how the rest of New Zealand must have looked and sounded before our ancestors arrived, bringing with them a motley Noah's Ark of wildlife killers.
Stewart Island is only an hour's sail from Bluff, but what a difference a strait makes.
Foveaux Strait is rarely a calm stretch of water - severe gale force winds are not uncommon and mountainous waves can roll in from all points of the compass, colliding in a maelstrom of white-capped sea.
But it is partly that treacherous stretch of water that gives Stewart Island its "otherworldliness".
The ferry crossing puts off some human visitors (you can opt for the 20-minute flight instead, weather permitting...) but perhaps more importantly it has kept many of our most efficient furry killing machines from decimating the island's abundant birdlife. Foveaux Strait is simply too far for ferrets, stoats and rats to swim across.
Stewart Island is not completely predator free but compared with the mainland it is a paradise for our flightless, semi-flightless and "too friendly for their own good" bird species. This can become obvious from the moment you step ashore.
Just a few metres from the wharf and tucked into a hebe almost within flipper distance of two fuel tanks, was a very rare Fiordland crested penguin. There are only about 3000 breeding pairs of these birds left in the world.
On our short walk up the hill to our rented cottage a pair of New Zealand kakariki or parakeet swooped past and three fat kereru (wood pigeons) lifted heavily into the air from a cliff-top grove of native fuchsia.
During our stay a kaka (native parrot), with its chestnut brown top feathers and vivid red patches under the wing strutted along the verandah rail, while peering inquisitively in the conservatory windows. Last time I stayed here, five kaka made regular visits, often checking to see if we were in by perching precariously on the guttering then leaning over upside down to look in the window.
With birdlife prolific even around Stewart Island's only real settlement at Oban on the shores of Halfmoon Bay, you hardly need to go further afield to see species that are either incredibly rare or even totally non-existent on the mainland.
But, there's nothing like joining an expert who really knows how to track down the more elusive wildlife.
Just over the hills to the south of Halfmoon Bay is Paterson Inlet, a natural harbour that all but cuts Stewart Island in two.
During the 19th century and early 20th century, whalers, sawmillers and settlers lived and worked around it shores. Today only the ghosts of their settlements live on - rusted boilers, foundations being swallowed up by forest - and apart from the marine farms in Big Glory Bay, Paterson Inlet is largely the domain of recreational anglers and holidaymakers.
In the middle of the inlet is Ulva Island, the only bird sanctuary in New Zealand that is accessible to visitors. The island is predator free after every last rat was removed by 1997. There was a brief scare last year when rats reappeared but they have since been eradicated once more.
I was fortunate enough to visit Ulva Island with a guide who can trace her Stewart Island ancestry back six generations on her European side and untold generations on her Maori side.
Ulva Goodwillie (and yes she was named after the island) seems to be naturally in tune with the wildlife and plants on "her" island.
Within minutes of our arrival by water taxi across the startlingly clear water of the inlet, she had found us the first saddlebacks any of our group had seen. There are only about 800 South Island saddlebacks in existence so even Ulva, who probably knew all of the island's birds by sight, jumped up and down with excitement to see them.
During our morning on the island we saw at least six of these birds, including several youngsters. We were lucky Ulva says, she'd recently spent more than four hours trudging aground the island with a National Geographic photographer just to find one.
The adult saddlebacks are striking birds with their bright chestnut saddles and red wattles. But their behaviour is fascinating too. Ulva told us the birds almost never fly unless they absolutely have to, instead they skitter around the forest floors and up and down tree trunks and branches.
Our loop around the island was accompanied in many places by the Stewart Island robin. About 20 of these endangered birds were transferred to Ulva Island in 2000-2001 and even after nine either flew back to the mainland or disappeared, the remaining population thrived and now numbers over 200 birds.
The robins hopped happily around our feet. As ground-feeders they took every opportunity to grab any insects we had stirred up in the leaf litter.
Ulva (both of them!) hadn't finished with the firsts. Deep in the most pristine part of the forest we encountered two riflemen, New Zealand's smallest native bird. At around 8cm long, these birds were spiralling their way up tree trunks looking for food. By now the chattering and the flash of the bright green yellow-crowned and red-crowned kakariki were almost beginning to seem commonplace.
We left Ulva reluctantly... literally rushing down to the wharf so we didn't miss our boat.
A family of saddlebacks had been putting on a commanding performance just before we emerged from the forest on to the beach.
When Europeans first settled around Stewart Island, Ulva Island was the post office (there being no roads) and when the mail boat came in the post master would raise a flag and everyone would row over to collect their post.
His house, now a holiday home, still stands on a small piece of private land that stretches down to a tiny curve of golden sand.
I suspect I wasn't the only one who left the island wishing I was one of the lucky ones able to spend my summers there.
