The Department of Conservation has this week completed its Battle for our Birds pest control in the Landsborough Valley, and the Abbey Rocks area around Lake Paringa.
The aerial application of cereal baits containing biodegradable 1080 pesticide was carried out on over 15,000 ha in the Abbey Rocks area and over 26,000 ha in the Landsborough Valley.
The pest control was carried out in order to halt a rat and stoat plague that was predicted to develop over spring and summer. Heavy beech tree seeding (mast) that has occurred in these forests leads to explosions in the numbers of rats, mice and stoats. Jo Macpherson, South Westland Biodiversity Manager says, “Stoats, rats and possums eat eggs, kill females and young on nests. Without pest control, we would see a poor breeding season with a very low survival rate of young, and unsustainable decreases in the adult breeding bird population.”
The Landsborough and Abbey Rocks sites are home to a range of vulnerable species – both plant and animal. The Abbey Rocks forests support a large population of kākā, and the forest is a stronghold for vulnerable plants such as red mistletoe, fuchsia and southern rata which are favourite foods of possums. The Landsborough is a stronghold for mōhua and mistletoe. Both the kākā and the mōhua are hole nesting birds that are extremely vulnerable to predation. Reducing pest numbers will also benefit other forest birds such as morepork, kākāriki/parakeet, bellbirds, kea, riflemen and fantails. Other native wildlife, including lizards, bats and insects like wētā, will also benefit from the knockdown of introduced predators.
The Landsborough and Abbey Rocks pest control is part of DOC’s Battle for our Birds pest control programme to protect vulnerable native wildlife from beech seed-fuelled predator plagues that could decimate their numbers. They are 2 of 26 confirmed operations using aerially applied 1080 over about 640,000 ha of South Island conservation land. Aerial 1080 predator control has been completed over about 80% of the total area so far.
Aerial 1080 pest control knocks down rats and stoats to undetectable levels with stoats killed through eating poisoned carcasses. It also reduces possums, which cause browsing damage to native vegetation and prey on native birds and their eggs.
Warning signs are in place at main public entrances to the areas covered by the pest control to advise the public of the risks of the pesticide and poisoned carcasses.
The Battle for our Birds aerial 1080 pest control has two separate phases —the sowing of non toxic 'pre-feed' bait, to encourage rats and possums to eat the baits, followed by application of biodegradable poison 1080-laced cereal baits at least five days later.
The 1080-laced cereal baits were sown at a rate of 1 kg per hectare. Each 6 g bait contains 0.9 g of 1080.
The coordinated Battle for our Birds pest control programme is targeted to protect the most at-risk populations of mōhua/yellowhead, kākāriki/parakeet, kiwi, whio/blue duck, kea, kākā, rock wren, giant land snails and native bats at sites across the South Island.