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Kea to benefit from Battle for our Birds
Fiona Oliphant
Kea are one of a dozen native species that are the focus of the Department of Conservation’s Battle for our Birds pest control programme designed to combat the effects of a bumper seeding in beech forests this autumn. Launched earlier this year by Conservation Minister Dr Nick Smith, it stands to be DOC’s largestever coordinated pest control effort, expanding the area of public conservation land under treatment from about five to 12 per cent. Battle for our Birds aims to protect the most vulnerable populations of forest birds, bats and other species at risk of being overwhelmed by rats and stoats as numbers soar later in the year. Aside from kea, target species include mohua/yellowhead, kaka, orange-fronted parakeet/kakariki karaka, rock wren, great spotted and tokoeka kiwi, long- and short-tailed bats/pekapeka and Powelliphanta giant land snails. Planning is now well underway for up to 23 aerial pest control operations and one bait station operation, covering 700,000 ha of South Island beech forest this coming winter and spring. All but three of the areas to be covered have remnant kea populations that would otherwise be facing a potentially devastating stoat plague. Details of the exact areas and timing of operations are still being finalised as the results of seed fall and rodent monitoring come in and DOC staff consult with affected communities. Stoat trapping is also underway at a number of the sites. Concerns were sparked last spring when beech forests throughout the country were seen to flower heavily. DOC scientists warned that there were signs of an 18
Photo: James Reardon
extensive beech mast (seeding) perhaps as big as the one in 2000 that led to predators decimating populations of mohua (yellowhead) and orange-fronted parakeet. The stoat plague that year was also the likely cause of the drop in kea numbers in Nelson Lakes National Park between 1999 and 2009. DOC ecologist Graeme Elliott explains that beech trees normally seed every 2-6 years but particular climatic conditions – a cooler
summer followed by warmer one – seem to trigger large-scale seeding events. “When we get heavy forest fruiting, rats and mice eat the seed and numbers rise rapidly to peak in the coming summer when stoat numbers also explode,” he says. “And when rodents and stoats reach plague proportions our native birds take an absolute hammering, particularly in spring when birds are nesting and raising chicks.” Experience over the past decade has shown that aerial treatment of 1080 is the most effective method to knock down rats and stoats over large remote areas before they overwhelm birds during the spring breeding season, says Dr Elliott. In late summer DOC rangers were out shooting branches from the canopy of beech trees at 23 sites from north-west Nelson to Fiordland to get an idea of the likely autumn seed fall. Results show that virtually all forests sampled were seeding in what is looking like a 10-20 year event.
Photo: Fiona Oliphant