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 ruggedness provides protection. The isolation offers safety. The difficulty is an asset.
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 1500 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. The adaptability is notable. The resilience is evident. The distribution is extensive.
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. Sight is secondary. Smell is primary. The bill is the tool. The soil is the source. The food is secured.
The population stands at roughly 15000 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. The landscape defends itself. The effort is minimal. The result is stability. For now. The buffer holds. The predators are limited. The birds survive.
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. The threat is periodic. The response is targeted. The decline is slow. The status is precarious. The management is essential. No one told it otherwise.