The survival of the mohua in the majestic, forested valley of Makarora at the head of Lake Wānaka is a fragile triumph, Jo Tilson says.
It seems for every small step forward the mohua population took in 2023, there was a countervailing tragedy, presenting a stark reality that without human help, the population will be completely wiped out within 10 years by predators.
Ms Tilson is a conservation contractor working with Southern Lakes Sanctuary (SLS) and Central Otago Forest & Bird; one of big army of people on the front line of the battle to save mohua from the fangs of stoats and rats.
"Raising our voice and our profile to ensure that retaining mohua in Makarora is an absolute priority. We are determined our story will not become another Goodbye Freddy story for Minister Jones," Tilson wrote in an article of the Forest & Bird magazine recently — referring to Resources Minister Shane Jones’s comment in Parliament in December that if a frog stood in the way of a mine, it was "Goodbye, Freddy".
Ms Tilson was also the author of a recent SLS report which evaluated the breeding success of Makarora’s mohua during last year’s beech mast event, consequent rat plague and the implications for the future.
The mohua population has been monitored since 2008.
The silver beech forest habitat has had 1080 drops before, but not last year. Traps were set instead — in fact trapping efforts doubled.
Mohua were also banded and monitored with acoustic equipment.
Ms Tilson’s report abstract says mohua breeding success was high within the areas that had bait traps, with 18 fledglings from nine groups of adults.
"Beyond this core areas, mohua numbers have plummeted and in some monitored sites, all but vanished," she said.
With SLS efforts expanding again this year, "nevertheless the Makarora mohua population is now severely at risk and is unlike to survive the next decade without serious intervention measures".
She recommends current predator control and monitoring efforts continue to expand.
She is also advocating more 1080 operations and translocation of mohua from other sites to boost numbers and genetic biodiversity.
"Without these measures, the population is doomed and the last survivors should be rescued and placed in offshore sanctuaries," Ms Tilson said.
Mohua (Mohoua ochrocephala) are endemic to the South Island of New Zealand and despite habitat changes and increasing predator challenges over 200 years, have persisted at Makarora.
But they have now disappeared from 85% of their former range.
Nesting females and chicks are particularly vulnerable and at Makarora, populations that were once considered mohua strongholds are now male-dominated.
Known as the bush canary by early settlers, mohua are small, insecting-eating, hole-dwelling birds with a vibrant colour and melodious song.
