This section of the Kepler Track stretches nine kilometers from the car park to Rainbow Reach. It's a quiet walk alongside the Waiau River connecting Lakes Te Anau and Manapouri. The track, through a relatively open canopy and a floor of dense ferns and mosses, is so soft and spongy that we met a young tramper walking barefoot. Numerous wooden traps along the trail, marked by pink or blue plastic triangles on trees directly above them, are part of a massive effort to reduce populations of introduced stoats and rats that have decimated New Zealand’s native birds. We came across a jolly volunteer trapper who lamented that the technology has not changed ever since he started trapping forty years ago.