An estimated 1382 rats were dispatched in traps and an estimated 3600 rats from the bait station network alone in Makarora for the 12 months up to November last year.
The collaborative efforts by conservation groups Southern Lakes Sanctuary, Department of Conservation (Doc) and the Central Otago Lakes branch of Forest & Bird have curbed the "rat plague" of the 2023-24 summer by installing over 700 bait stations, servicing more than 1400 traps and undertaking a 1080 operation across the Makarora area over the past 15 months.
A family of endangered whio (blue duck) with five youngsters have been observed on the southern end of the Young River over recent months.
Southern Lakes Sanctuary project director Paul Kavanagh said the whio sighting was an excellent reward following the localised conservation work.
"The presence of whio in the Young River is an optimistic sign that indicates good stoat control in the area, which comes down to the great collaborative effort last summer," he said.
"These endemic manu (birds) nest on the banks of rivers, in caves or in dense vegetation, and nesting whio are very vulnerable to stoats."
Central Otago Lakes Forest & Bird chairman Andrew Penniket said extensive trapping was one of the factors for the increased presence of the birds.
"The whio family has been seen over the space of a month by several groups and is the largest number seen on this river, or in our catchments, in our collective memories," he said.
"The sightings are a wonderful reward, coinciding with the work undertaken to put an extra 20 traps into the southern end of the Young River, specifically for the protection of rock wren and whio.
"It has been heartening that we have had very low catch rates of rats and stoats on all our trapping lines. It is probably the lowest ever, that I can recall."
In the summer of 2023-24 rat numbers exploded due to a "mast season" of native beech trees, during which a larger number of tree seeds are produced.
"We were concerned about the survival of the endangered mohua (yellowhead) with the siege of rats swarming to the area last spring and summer," Mr Kavanagh said.
"However, in the core trapping and bait station areas, most of the mohua chicks that we have monitored have survived in both this year’s and last year’s breeding seasons."
This area is a priority site for Doc’s national predator control programme and as such received landscape scale predator control via aerial 1080 in March 2024, in response to rodent plagues following beech masts. Working in partnership with Doc ensures the best outcome for predator control.
Introduced predators such as rats and stoats kill more than 25 million native birds and wildlife every year in New Zealand.
— APL
