Its preferred habitat consists of coastal and cliff herbfields, Carex grassland, tussock-herbfields and forest. The one clutch seen in the wild consisted of two eggs (Elliott et al. 1991). On both islands L. muelleri is most often heard and seen in areas dominated by the megaherbs Anisotome latifolia, A. antipoda, Pleurophyllum criniferum, P. speciosum, and Stilbocarpa polaris (Miskelly et al. 2020). These plants are highly susceptible to browsing and uprooting by ungulates, rabbits, and pigs and the loss of these plants from islands in Port Ross may have contributed to the local extinction of rails. One juvenile bird caught in the wild lived for nine years in captivity, and ate insects and other invertebrates (Heather and Robertson 1997, Taylor and van Perlo 1998).

Lewinia muelleri is endemic to the Auckland Islands, New Zealand. It was once thought to be extinct but was rediscovered on Adams Island (100 km²) in 1966 and Disappointment Island (4 km²) in 1993. It is likely that they historically occurred on most of the Auckland Islands but vegetation changes, predation and competition from introduced species is thought to have caused their extirpation (Elliott 2013).

Conservation Actions Underway
The islands are nature reserves part of a World Heritage Site declared in 1998 and access is strictly controlled. Both islands this species persists on are subject to strict biosecurity measurements to minimise the risk of introducing non-native species.

Conservation Actions Proposed
Conduct surveys to obtain an up-to-date estimate of the population size. Monitor population trends through regular surveys. Eradicate pigs from Auckland Island in the long term (B. D. Bell verbally 1999, A. D. Roberts in litt. 1999). Transfer birds to other suitable pest-free islands in the Auckland Island group (A. D. Roberts in litt. 1999).