Stewart Island has become synonymous with kiwi spotting in the wild, something that is difficult to do on mainland New Zealand. Tours from Oban include kiwi spotting, but most people are keen to get to Mason Bay, on the west coast, where they stay overnight in the DOC hut and head out after dark in the hope of finding these elusive creatures. You’ll almost certainly hear them, and have a fair chance of seeing them provided you don’t go crashing about in the bush: just pick a spot and wait. Take a torch, but keep the beam pointed to the ground to avoid disturbing the birds.
For hardy visitors, the cheapest way to visit is to walk (38km one-way; 13–15hr) along the southern leg of the North West Circuit, probably staying overnight at Freshwater Hut. You can save a lot of time by catching a water taxi from Oban to Freshwater Landing Hut (40min) then walking to Mason Bay (15km; 3–4hr; flat but often flooded – check conditions before you head out).
Stewart Island Flights offer a “Coast to Coast” loop, flying from Oban to the beach at Mason Bay (not at high tide), staying a night or two there, walking to Freshwater Landing, then getting a water taxi back to Oban (or vice versa).