The takahē’s ecological niche

Takahē (Porphyrio hochstetteri) once lived throughout the South Island. Their original habitats were the bushy edges of lowland swamps and rivers. Today’s remnant takahē population lives in the harsh environment of the Murchison Mountains in Fiordland. This wild, alpine habitat is less than ideal, but scientists believe that takahē survived there because of its remote location. The rugged area was relatively isolated from the main threats to takahē: humans, deer and introduced predators.

The surviving population has likely been in the Murchison Mountains long enough to adapt to the mountainous conditions. The Department of Conservation notes that takahē are well suited to cold, damp environments.

Ecological niche

An ecological niche is the role and position a species has in its environment and how the environment supports the species’ needs.

In their natural alpine habitat, takahē get their food and shelter from alpine grassland species such as snow tussocks, sedges and rushes. The food is low in nutrients. As a result, takahē need to eat continuously – up to 19 hours a day. The food is also very fibrous and can’t be digested – takahē produce around 8 metres of poo daily. Droppings deposited in rows are called latrines.

When heavy snow covers their alpine grazing areas, takahē move down to the beech forests. There they eat the starchy rhizomes of thousand-leaved fern (Hypolepis millefolium) and cutty grass (Carex coriacea).

Takahē are mostly herbivorous but they do collect insects such as beetles, wētā and moths to feed to their chicks. Takahē are naturally predated by kārearea (New Zealand falcon).

Breeding pairs of takahē build raised ground nests using snow tussock leaves. Males and females take turns incubating the eggs and share chick rearing.

New homes away from the alpine tussock habitat

Takahē have been moved or translocated to various places around New Zealand. In 2018, takahē were released into the tussock grasslands of Gouland Downs in Kahurangi National Park at the top of the South Island. The site was chosen because the habitat is quite similar to the Murchison Mountains, although the climate is warmer.

Takahē have also been relocated to offshore islands and mainland sanctuaries. These habitats are considerably different from alpine tussock areas, but they are also pest free. The birds prefer to live in grassland areas but spend some time in the forests too. They feed on pasture grasses and may receive supplementary (top-up) feeding.

Structural and behavioural adaptations

Takahē evolved in the absence of ground-dwelling predators. This meant that, like kiwi, takahē developed a large body size, small wings and strong legs. On average, an adult takahē weighs 2–3.5 kg and stands about 500 mm high. This large body size is an advantage to species that live in cold environments.

Their beaks are also very strong. Takahē use their beaks to snip softer grasses and herbs that are down low to the ground. Takahē also 'tiller' by tugging the side blades (called tillers) from tussock plants. Takahē hold a blade down with one foot and use 10-15 kg of force to remove the tough outer sheaf. This exposes the inner core – the most nutritious part of the plant. When the grasses are in seed, takahē strip the seeds by running their beaks along the stem. These methods of feeding do not destroy the native grasses. The birds browse from the side rather than from above where the growing shoots are. The native plants also evolved along with the takahē, so they’ve adapted to the birds’ habits too.

Takahē live in breeding pairs or small family groups. They are very territorial and defend their breeding habitats, which can range from 5–60 hectares depending on the quality of the habitat. Their territorial behaviours mean that only a few takahē can live on offshore islands or in mainland sanctuaries because of the limited amount of land available.