Letter: 1080's secondary poisoning effect
I note with interest the proposed increase in use of toxins (1080 poison) in our conservation estate.
Primary under justifications for this ''toxic shock'' is the protection of vulnerable avifauna species by the control of rats, stoats and possums.
Possums while impacting on some bird species (though hugely dependent upon other ecological factors) are not the primary driver for the decline in numbers of vulnerable species.
In my understanding, 1080 is registered in this country primarily for poisoning possums.
If that is the case then is DOC intentionally relying upon the secondary kill of mustelids and rats and planning control operations under the justification of this ''secondary poisoning'' effect?
If so, is this legal?
Director-general of conservation Lou Sanson replies: 1080 is registered for both possums and rats.
The label states: '' Bait in Pellet form for Poisoning of Possums and Rodents. Contains 1.5g/kg sodium fluoroacetate in the form of a bait''
DOC's operation will be directly targeting rats and possums using cereal baits.
While stoats are not on the label, there will be a beneficial by-kill of stoats as a result of them eating poisoned rats and possums. This by-kill is not illegal.
A widespread rodent and stoat plague in South Island beech forests would put some of our most threatened bird species such as mohua/yellowhead and kakariki karanga/orange-fronted parakeet, at serious risk of extinction.
Stoats are a major threat to the viability of many native species populations and in the context of a beech mast, will pose an unacceptably high threat to the viability of populations of many native species.
It's been estimated that, with no pest control response, we might lose about 75 per cent of the remaining mohua population - or more than 3500 birds.
In 2000, a widespread beech mast and resulting predator plague caused the local mohua population in the Marlborough Sounds to go extinct.
Orange-fronted parakeets in Canterbury beech forests also took a big hit in 2000 with one population lost from the Hurunui North Branch and an 85 per cent decline in the Hurunui South Branch population.
A total of just 200 to 400 of these birds now remain in three beech- clad valleys-the Hawdon and Poulter valleys in Arthur's Pass National Park and Hurunui South Branch in Lake Sumner Forest Park.
The Southland Times