"Remember the three rules," whispers Greg. "No talking, no flash photography and no getting closer than I am."
We all nod in silent agreement and follow him in single file along the beach. We walk above the high tide mark, the Southern Pacific Ocean pounding the foreshore to our right. In the encroaching darkness I can just make out the silhouetted figures of the rest of the group. Up ahead, Greg's flashlight scans the sand like a metronome.
Suddenly, there's an angry bark and everyone stops. It's a Hooker's sea lion. "Don't worry," says Greg, "we've never lost a tourist to a sea lion yet."
We give it a wide berth and continue. Hooker's sea lions are one of the world's rarest species of sea lion but that's not what we've come to see.
A few minutes later Greg zeroes in on some movement in the distance. We tentatively creep closer to discover a curious-looking creature shuffling around in the kelp. A frisson of excitement passes through the group. This is what we've come to see.
Don't worry,we've never lost a tourist to a sea lion yet.Greg the guide
Before today, I'd only ever seen a kiwi on a stamp. In the flesh it's bigger than I expected but just as bizarre. With its bulbous body, hunched back and long beak, it looks cumbersome and vulnerable, but it can outrun a human and is fiercely territorial.
Located 30 kilometres south of New Zealand's South Island, Stewart Island is the only place in NZ where kiwis aren't considered endangered. There's thought to be a population of around 18,000, vastly outnumbering the island's 400 or so residents.
Stewart Island brown kiwis are quite different from their mainland relatives. For a start, they're diurnal, feeing both during the day and night, making them easier to spot. They also have a different family dynamic – males share incubation duties and chicks stay with their parents for up to two years – much longer than on the mainland.
Greg has christened this bird Midway Meg and we watch by torchlight as she rhythmically dips her beak into the sand to feed on sandhoppers, occasionally pausing to snort sand from her nostrils.
Kiwis are the only bird with nostrils at the end of their beaks and their powerful sense of smell allows them to find food buried four inches below the surface. In proportion to their body they have the largest feet and lay the largest egg of any bird. A fully developed egg takes up an eye-watering two-thirds of a female's body space.
We leave Midway Meg and continue our search. It's now inky black and I carefully position myself in the middle of our group of 12 in case Snarky the sea lion is still lurking about.
Greg finds a new set of tracks which lead us to another of the tour's regulars – South End Sue. Unfortunately, she has company. A few metres behind her is a large sea lion and when it sees the flashlight it barks and starts coming towards us. "OK. Let's get out of here," says Greg.
We retrace our steps until we find the 250-metre-long boardwalk that takes us back to the wharf on the other side of the peninsula. Skipper and owner of Bravo Adventure Cruises Philip Smith is waiting with welcome hot cups of tea, coffee and hot chocolate.
During the 30-minute boat ride back to Stewart Island's main settlement, Oban, Smith tells me that the peninsula isn't necessarily the best place on the island to see kiwis but it's the most easily accessible. He's been running the tour for 26 years under a concession from the Department of Conservation that allows him to take up to 15 people each night. Sightings aren't guaranteed but in the last six years he's only had two tours that have drawn a blank.
At $125 a person the tour isn't cheap but the consensus among today's group is that it's worth it. David Attenborough is certainly a fan. After spending four days here, he raved, "It was one of those amazing encounters with a charismatic creature. An animal which is rare and strange but totally oblivious of you."
Bravo Adventure Cruises' kiwi spotting tour leaves at sunset so departure times vary throughout the year; tours fill quickly so book ahead. See kiwispotting.co.nz.
Adventure South's seven-day South Island multi-activity adventure includes visits to Stewart Island, the Catlins, the Otago Peninsula, the Tasman Glacier and an overnight cruise on Doubtful Sound. Cost from $2980 Phone 1800 10 70 60, see advsouth.co.nz.
The writer was a guest of Air New Zealand, Adventure South and Tourism New Zealand.