Date:  17 November 2015 Source:  Office of the Minister of Conservation

A heavy seeding in beech forests, known as a mast, could lead to a rapid rise in rat and stoat numbers, putting vulnerable native birds at risk. The last mast took place in the summer of 2013-14.

"DOC's monitoring and prediction models show that there may be a large beech seeding next year and that heavy flowering has begun in both the North and South Island forests," Ms Barry says.

"A beech mast would cause rat numbers to boom due to the abundance of seed available as food, and when they germinate millions of hungry rats would then threaten native wildlife such as the mohua/yellowhead, whio/blue duck and kiwi."

"However, it is still too early to tell whether a mast event on the scale of 2014 will occur, as a sudden weather event such as a cold snap could prevent it. DOC will continue to closely monitor the situation. We will not know for certain if the mast will happen until early next year."

DOC's successful Battle For Our Birds, the largest pest control operation undertaken in New Zealand, was launched in response to the last beech mast in 2014.

It saw more than 600,000 hectares of conservation land treated with aerial 1080 drops, expanded trapping and poison bait stations. As a result 95 per cent of rats and 85 per cent of stoats in targeted areas were killed and birds showed much improved breeding success rates compared to areas without pest control.

"1080 remains the most effective tool for pest control in rugged, difficult country and its use is essential for the protection of our native species."

Ms Barry says DOC will be ready to deal with another mast event should it happen next year.

"Over the past few weeks I have been discussing funding options to meet a potential mast with my colleagues. No firm decisions will be made until we know whether the mast will happen. However, I am confident DOC will handle the challenge and protect our vulnerable birds if it does."

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