Mātātā fernbird. Photo: Craig McKenzie
On a sunny day, the view from Florence Hill lookout in the Catlins is stunning. Expansive bush rises from the coast to the surrounding ridgelines. The crescent of golden sand that is Tautuku Beach stretches down to a rocky peninsula. And just where the beach ends, before the peninsula begins, is where the Tautuku River completes its journey into the sea.
The Tautuku, and its tributary the Fleming River, are quite special for this south-east coast - both are enclosed in native bush from their headwaters to the sea.
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This catchment is home to an array of native wildlife - red- and yellow-crowned kākāriki, the Tautuku gecko, titipounamu, non-migratory Gollum galaxiids and some secretive wetland birds. However, it's also home to a host of introduced mammals. Both the meat-eating and plant-eating kinds.
The pest problem
In the bush, Gavin White can read the signs of who has been through. Dropped leaves on the forest floor means possums have been gnawing at the stem junctions, tiger stripes of peeled bark were made by deer - when they encircle the whole tree, it will die.
Introduced browsing animals clear out all the palatable saplings and strip the undergrowth bare - essentially becoming the filter for the next generation of forest, which will be a poorer subset of what it once was.
View from Florence Hill of Tautuku Beach and part of the Lenz Reserve in the Catlins. Photo: Claire Concannon / RNZ
Gavin works in pest control for Forest & Bird, part of a team involved in the Tautuku Ecological Restoration Project.
The largest Forest & Bird-owned conservation area is found here. The Lenz Reserve is 550 hectares bought by the environmental charity in 1964, using funds bequeathed by Mrs Lenz.
But the project is wider than just the reserve. It's surrounded by land owned by the Department of Conservation (DOC) and the current pest trapping network extends across thousands of hectares.
Local community, iwi, Forest & Bird volunteers, DOC and contractors are all working to try keep the forest invaders at bay, and to help the threatened native inhabitants.
Forest & Bird pest control officer Gavin White. Photo: Claire Concannon / RNZ
Monitoring the mātātā
And it's not all bush. There are some clearings rich in native plant diversity, and several different wetland types. The Lenz Reserve encompasses some of the lower catchment of the Fleming River, part of which is a freshwater wetland area.
Just beyond a short walk that has relics from the sawmill era of the area, the stable ground gives way to soft, muddy patches and deep channels of peat-coloured water. It's here that Forest & Bird Tautuku Ecological Restoration Project manager Francesca Cunninghame has been monitoring mātātā or South Island fernbird.
Searching for mātātā. Photo: Claire Concannon / RNZ
A small, delicate, sparrow-sized bird with a characteristic long narrow tail that droops behind them as they fly, these cryptic birds are more often heard than seen.
The mātātā is classified as 'at risk - declining', so Francesca is keen to help this population as much as she can, but they also act as a good 'indicator species'. Because they have long breeding seasons (August to February) in which they can incubate and rear multiple clutches, they can do very well in areas where there is effective predator control.
They are also territorial, so Francesca knows approximately where each resident pair is likely to be building their nest, whether it's the first go, a follow-up clutch, or a second try after a nest fail.
Francesca Cunninghame and Niko Jimenez-Cunninghame. Photo: Claire Concannon / RNZ
In hindsight, their first season of monitoring was the most successful, says Francesca. "The wetland just sort of filled up with fernbirds." There was only one nest predated that season.
But in seasons two and three, trail cameras pointing at the nests revealed that stoats and a feral cat were targeting the eggs and chicks. Unfortunately, the story of predation is continuing for this year - Francesca has footage of a stoat snaffling eggs twice from one of the pairs.
South Island fernbird nestlings at Lenz Reserve. Photo: Francesca Cunninghame
It serves as a reminder about the difficulties of pest control, Francesca says. "Just putting out traps and tallying up the things you catch - it's not really an outcome. Because for us, it doesn't matter how many stoats we might catch, if there's just one single stoat in this wetland or one feral cat that's got on to fernbird nests, you know, it could have a real impact on the birds that season."
Listen to the episode to learn more about the team's pest control efforts, and how the mātātā are doing this breeding season.
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