Takahē are one of New Zealand’s conservation success stories. Their conservation status has moved from extinct to nationally vulnerable in the 70 years since they were rediscovered in the Murchison Mountains in Fiordland.
Small population numbers
Although takahē once lived throughout Te Waipounamu South Island, their population numbers may never have been large. Subfossil records provide scientific evidence of the birds’ existence in multiple locations. However, the only clear references to takahē in Māori oral histories come from Māori living in Southland and Fiordland.
It is possible that takahē may have been in decline prior to the arrival of humans. Takahē are specialised tussock feeders. Grass and scrublands were replaced by forests in the late Pleistocene and Holocene periods. Takahē numbers may have decreased with the disappearance of some of their habitat.
Regardless of the natural population numbers before human arrival, it is clear that we’ve created a number of threats to the birds’ continued existence.
The impacts of human migration
Polynesian immigrants were the first to have significant impacts on Aotearoa New Zealand’s natural environment. Takahē were hunted for food and predated by the introduced kiore (Pacific rat) and kurī (dog). Habitats were modified through the use of forest fires. By the 1840s, takahē were very rarely seen and were officially declared extinct in 1898 – before being rediscovered in 1948.
The takahē survived in the Murchison Mountains of Fiordland due to the rugged isolation. This area is effectively a peninsula – steep terrain surrounded on three sides by Lake Te Anau – making it difficult for humans and predators to gain access. Takahē may have been safe in this location for centuries, but Europeans brought in animals that are well adapted to live in the harsh tussock habitat.
Habitat destruction by red deer
British red deer were first released in the South Island in 1851 and became established in the Murchison Mountains during the 1930s and 1940s. Deer compete directly with takahē for food. Both species feed on snow tussocks, and both prefer the tussock varieties that contain the highest nutrients. Deer graze from above and eat the green leaves. Repeated grazing weakens and kills the tussocks. Takahē graze from the sides of the plants using a method that does not harm the tussocks.
Following the rediscovery of takahē in 1948, scientists quickly began to identify the animals that could threaten the birds or their habitat. They decided the most serious threat was posed by deer. Deer control began in 1948, and 35 deer were culled. As the years went by, deer numbers remained high. The Forest Service (forebears of the Department of Conservation) took over in 1962, and a year later, the deer herds were significantly reduced. In 1975, hunters began to use helicopters. The deer population was finally brought under control, but it was almost too late. Tussock is slow to recover from heavy grazing, and the takahē population had begun to collapse. By the early 1980s, just over 100 takahē remained.
Predation by stoats
Stoats were released in 1884 to control rabbits and hares in the Canterbury region. Like deer, it did not take long before they became established in other parts of the South Island. Very early on, stoats were recognised as a threat, but they only attack takahē when their preferred food sources are scarce.
In 2007, during a beech and tussock mast event, the Murchison Mountains were overrun by stoats. They reduced the takahē population by half. In response, the Department of Conservation extended its stoat trapping programme to cover all of the 50,000 hectare Special Takahē Area in the Murchison Mountains.
Severe weather can threaten the takahē population. For example, severely cold winters and avalanches can adversely affect population numbers. Because of this, the Department of Conservation has established a second wild population of takahē in Kahurangi National Park. The tussock habitats in Kahurangi have good predator control and do not experience extreme temperatures.
Another challenge to takahē conservation is that takahē are very territorial. Their territories range from 5–60 hectares, depending on the quality of food and the time of the year. This limits the number of takahē that can be placed in offshore islands and predator-free sanctuaries.
Nature of science
Scientific knowledge contributes to new technologies. As scientists and engineers learn more about predator behaviour, they are able to design more effective predator control. The Department of Conservation uses 2,500 stoat traps in the Murchison Mountains. Ongoing research and testing has made the traps more effective and humane.
1080 and pest control – a timeline includes a section on introduced pest mammals.
The article Conservation rankings explains the ranking systems used by the International Union for Conservation of Nature and the New Zealand Threat Classification System.
Check out the Department of Conservation’s Takahē Recovery Programme.