Pīwauwau are listed as nationally endangered under the New Zealand Threat Classification System. They are small, ground-feeding birds found only in the Southern Alps of the South Island. It remains above the bush line throughout its life, nesting under large boulders at the foot of screes and rock falls and feeding on insects. In summer rock wrens hop and buzz about on short rounded wings. Once winter snows arrive, they survive in pockets of space in their rock or scrub shelter. They are poor fliers, rarely flying more than two metres off the ground or for distances more than 30 metres.
The population is small and declining, as its habitat of alpine basins and habit of hole-nesting on the ground leads to predation by mice and stoats.
They are found in the alpine parts of the Routebun and Dart valleys, such as the Harris Saddle basin above Routeburn Falls Hut.