Between 1993 and 2018, the number of Rakiura tokoeka (Apteryx australis australis, Stewart Island brown kiwi) territories in 125 ha of retired farmland near Island Hill Homestead, Mason Bay, declined from 17 to 12 at a mean rate of 1.43% per year, and the minimum number of adults declined by 1.39% per year. These rates triggered a New Zealand conservation status of ‘Nationally Endangered’ for the subspecies assuming that they were typical of the whole of Stewart Island/Rakiura. Feeding habitat for tokoeka has been lost as the study site reverts from rough pasture to flax (Phormium tenax) and scrub; the mean mass of adult birds has decreased by 7.5% over 30 years despite a 30% decline in population density. Key predators of adult kiwi are absent, and predation of Rakiura tokoeka by feral cats (Felis catus) is known but is likely to be insignificant. With a conservative population estimate of 15,000–20,000 adults, and with the decline likely localised at Mason Bay, the conservation status of Rakiura tokoeka is more appropriately classified as ‘At Risk – Naturally Uncommon’. This research highlights the risks of extrapolating results from a single study, in this case with a limited geographical extent rather than a limited duration.