Fiordland is not easy country. The terrain is steep, the rainfall is measured in metres per year, and the forest is dense enough that conducting any systematic survey requires a substantial tolerance for physical discomfort and sustained disorientation. For the southern tokoeka, this is entirely the point. The same conditions that deter field researchers also deter stoats, ferrets, and dogs well enough to sustain a kiwi population that would otherwise require the kind of intensive management that most of the country's remaining kiwi depend on to persist. The Fiordland tokoeka is a large, rufous-brown bird with the standard kiwi construction: small head, long pale bill with nostrils at the tip, vestigial wings, stout legs, and no useful tail. Males weigh up to 2.8 kilograms, females up to 3.3 kilograms, placing them among the largest brown kiwi. They occupy an unusually wide altitudinal range, from coastal forest through to subalpine shrubland at 1,500 metres, moving through terrain that most kiwi species would not attempt. The range of habitats they occupy is broader than any other kiwi manages on the New Zealand mainland. Like Stewart Island birds, some Fiordland tokoeka live in family groups with helpers assisting the breeding pair, an arrangement not fully explained but one that appears to confer territorial and incubation advantages. The male's ascending whistle and the female's deeper, hoarser call carry through the forest at night, establishing territorial boundaries across steep country where visual contact is rarely possible. The diet is earthworm-heavy, supplemented with larvae, spiders, and occasional fruit, gathered by probing from a bill whose sensitivity to pressure and smell makes vision largely redundant. The population stands at roughly 15,000 birds across Fiordland National Park and the surrounding larger islands. Only about nine percent is under active management, a low figure by kiwi standards, but the terrain creates a natural buffer unavailable to most habitats. Predator numbers in remote Fiordland are held in check partly by the same ruggedness that makes the country so difficult to work in. Where the buffer breaks down is during beech mast years. Heavy seeding drives rat populations upward, stoat numbers follow, and kiwi chick survival drops sharply. Aerial predator control operations during mast events help keep the population from declining faster. Without those operations, the one percent annual decline would likely be considerably steeper. DOC classifies the species as Nationally Vulnerable: not facing imminent extinction, but not stable without continued effort either.