Makarora Mohua

A rare song still rings in the Makarora Valley — and we’re doing everything we can to keep it that way.

Mohua — the sparrow-sized songsters with bright yellow heads that adorn New Zealand’s $100 note — were once one of the South Island’s most common bush birds. Today, they’re in serious trouble.

The Makarora Valley is home to one of only 30 populations of mohua left in New Zealand — a pocket of hope where this taonga species still holds on. But their future hangs in the balance.

Thanks to a major collaborative effort between Southern Lakes Sanctuary, the Central Otago Lakes Branch of Forest & Bird (COLB), DOC and funding partners like the Otago Regional Council’s EcoFund, protection for mohua here is reaching new heights.

A breeding season with promise

In the 2023/24 summer, predator numbers were dramatically reduced — thanks to both an aerial 1080 operation in April 2024 and sustained ground-based trapping and bait station work. This meant that mohua entered the spring breeding season with far less predator pressure than the previous year, when a rat plague severely impacted the population.

The results were encouraging:

• 5 out of 6 monitored mohua groups successfully bred

• Each pair raised 1–4 fledglings

• An additional group is likely to have bred but was not confirmed

• Over 50% of mohua banded in 2023 were re-sighted in 2024

• Of the 6 pairs that bred in 2023, only 2 stayed together in 2024… mohua scandal!

These outcomes speak volumes — not only about the resilience of mohua but about the strength of the collaborative mahi protecting it.

Expanding the protection zone

To build on this momentum, we’ve now completed Phase 1 of our bait station expansion. A new grid at Cameron Creek has extended the mohua protection zone, complemented by the creation of the new “Mohua Loop” trapline — increasing the total number of traps in the area to over 1,500.

These additions enhance the continuous protection zone across the main valley floor — a critical step in buffering mohua from the ever-present threat of predation.

A second round of trap calibrations, two years after the first, proved invaluable, with several traps requiring adjustment. Routine clearing and maintenance of hundreds of kilometres of traplines continues to be a priority — ensuring that COLB’s incredible volunteer force can work as efficiently and effectively as possible.

Tech meets manu: tracking mohua by song

In another exciting development, this project is working with Digilabs on a groundbreaking acoustic monitoring project.

Here’s how it works:

• Acoustic recorders are placed in mohua territories, particularly where we have banded birds

• Digilabs turns the birdsong into spectrograms — visual representations of sound

• Using advanced AI (a Vision Transformer model — think ChatGPT for birdsong!), they’re developing tools to identify individual mohua by their unique calls

If successful, this could revolutionise how we monitor elusive species like mohua — helping us track individual birds from year to year without ever needing to see them.

Stay tuned for more from this innovative work.

A legacy of care

Mohua conservation in Makarora didn’t begin yesterday. COLB volunteers have been active here since 1998, with annual mohua monitoring starting in 2011. Since 2021, Southern Lakes Sanctuary has stepped in to expand and support this critical work in one of our most important management zones.

We’re proud to be building on this legacy — and grateful to all our partners and funders helping make it possible.

Thank you to the ORC EcoFund for your support of this essential mahi.

But we’re not there yet

Despite these promising results, mohua remain in serious trouble.

The population in Makarora is small, fragile and surrounded by predator-prone habitat. One bad season, one rat plague, one lapse in control — and everything we’ve gained could be lost.

To secure the future of mohua, we need to keep expanding, keep innovating and keep the pressure on.

You can help:

• Donate to support frontline conservation work

• Volunteer your time to help maintain traplines

• Partner with us to protect this special place

Together, we can make sure the song of the mohua continues to echo through the forests of Makarora for generations to come.