Today marks 75 years since takahē were rediscovered in the remote Murchison Mountains in Fiordland National Park. With just over half the population now living in the wild, takahē still have a number of challenges ahead of them. Here is an update on what is happening in the population.
The 2021 takahē population statistics are now in! With recent annual growth rates of 8-10%, you might have been betting on whether takahē would reach 500 this year……….unfortunately, however, the population has experienced a small decline. Five birds down from last year’s count (around a 1% decrease), 2021’s estimated total takahē population is 440.
This is the first decline for takahē in eight years. But before anyone hits the panic button – this isn’t a failure or a slip back towards extinction. It does, though, highlight the challenges of returning takahē to the wild.
Let’s look at why takahē had a tough year, why the result isn’t a surprise and what’s next for the Takahē Recovery Programme……
2021 was a large stoat plague year in Fiordland
Following the 2019 beech mast (heavy seeding), Fiordland experienced a surge in stoat numbers. Despite the extensive trapping network across the Murchison Mountains, around 10% of the Fiordland wild takahē population was lost. Chick and juvenile deaths were likely to be even higher. So, disappointing as the overall population decline is, once the severity of the stoat plague and subsequent predation levels were understood, the result was not unexpected.
On a more positive note, the stoat plague impact on the total takahē population was less significant than previously recorded plague yearsIt’s anticipated the rapid population growth experienced in the previous five years, will return next year and in future years when stoat numbers aren’t elevated. In comparison, the 2007 Fiordland stoat plague event led to a 25% drop in the total takahē population, which took the programme nearly a decade to recoup.
Further north in Kahurangi National Park, the Gouland Down’s takahē population declined by an estimated 18%. All five deaths were linked to environmental factors, including three drowning in a flooded river and presumed limited food availability outside of a heavy tussock seeding year.
More manu in the wild, more risks
More than half (52%) the takahē population now lives in the wild. That’s nearly double the wild:non-wild ratio in 2014 and it marks a significant milestone for takahē recovery! However, with a higher proportion of takahē in their natural habitat, periodic pressures, such as predator surges and environmental conditions, will likely lead to fluctuating takahē numbers.
You might ask: “why not put more takahē in predator-controlled sanctuaries where risks are reduced?”. The simple answer is, due to their small size and locations, island and mainland sanctuaries can’t provide a sustainable long-term solution for takahē recovery. The current network of takahē sanctuaries provides valuable safe breeding grounds and holds enough breeding takahē to secure against loss of genetic diversity or extinction. To progress the takahē recovery goal of restoring this taonga as a functioning part of their natural grassland ecosystems, takahē must return to the wild.
The takahē population is in good health, with a productive breeding programme
Overall population numbers only paint part of a species recovery story. To be successful, it’s crucial populations have large numbers of breeding pairs (i.e a relatively even female:male ratio to produce young) and good genetic diversity (particularly to avoid inbreeding). The takahē population is scoring strongly in both areas, with breeding pairs up to 143 and genetic measures showing increasing representation of the available diversity across the population. These factors, coupled with the programme’s productive breeding engine, provides takahē recovery with resilience. The secure breeding sites allow accelerated growth in a good year, and keeping the population stable in a tough year.
Takahē need advancements towards a predator free Aotearoa
DOC’s Takahē Recovery Programme, with Ngāi Tahu and national partner Fulton Hogan, has solved the “making good quality takahē efficiently” part of the puzzle – the challenge now is to progress returning the species to the wild. As wild takahē numbers grow, the Takahē Recovery Programme is transitioning from intensive individual bird management to an overall population management model.
With intensive trapping efforts insufficient to allow wild population growth during a stoat plague year, providing safe wild sites for takahē is reliant on advancements towards a predator free Aotearoa. The Takahē Team will continue to work closely with others to investigate ways to reduce the impact of stoat surges on wild takahē, including increasing knowledge and development of new predator control tools.
From here, the programme will continue to monitor and learn from the wild takahē populations. This will inform future selection of wild sites and how we can successfully establish and manage these populations.
2020/2021 was a tough year for takahē, but the Takahē Recovery Programme whānau are in it for the long haul. Rest assured it won’t be long before we can celebrate the 500 manu milestone.