The greater good
The greater good
More than 90 species of birds are found only in New Zealand, but aside from two species of bat, there are no native land mammals.
Mammals are very susceptible to 1080, but metabolic differences mean that birds and other animals such as insects are less vulnerable. As a result, 1080 is well suited for use in New Zealand to target introduced pests such as possums, stoats and rats. In other countries, conservation managers cannot apply 1080 without putting their own native mammals at risk. This is why New Zealand is often cited as the world's biggest user of the toxin.
1080 operations have little or no impact on many of our native species. Independent studies on freshwater animals such as eel (tuna) and crayfish (kōura) have found no significant effect of the toxin, even when deliberately exposed to 1080 baits at ten times the quantity expected after aerial operations. These studies also showed that although eels that scavenged contaminated possum carcasses contained low levels of 1080, the eels excreted this naturally, with no discernible impact.
Pest control benefits forests and allows
native wildlife to thrive
Native invertebrates are also at minimal risk from 1080. Direct counts and studies using pitfall traps to monitor ants, beetles, weevils, illipedes, mites, slugs, snails, spiders and cave wētā have shown no significant change in population numbers after an aerial operation. Separate studies on giant and tree wētā also found no negative impacts from 1080.
While some plants can absorb small amounts of 1080, studies show they also process it naturally without impact. Research at Lincoln University found that levels of 1080 in plants were so low that a 70-kg person would need to eat over 2 tonnes of pūhā that had been exposed to 1080 baits in one sitting to put themselves at significant risk.
Studies have shown that birds such as kiwi, kākā and kōkako are not vulnerable to 1080. More than 200 kiwi have been monitored through 1080 operations-some for up to a year-and none have died as a result of 1080 poisoning.
Some native birds-particularly smaller, lighter species such as tomtits (miromiro)- were susceptible to small fragments of carrot bait associated with early aerial 1080 operations. Consequently, DOC has made a number of management changes to minimise the risk of 1080 to vulnerable birds. This includes 'screening' to filter out small fragments, a shift from carrot towards cereal-based baits, and the replacement of raspberry lures with green dyes spiked with cinnamon. Recent research has shown that 1080 packaged in large cereal baits with cinnamon and applied at low sowing rates has little, if any, impact on tomtit populations.
Studies in the Tongariro Forest have shown that kiwi chick survival jumped from 27 percent to 69 percent in the year after aerial operations against predators, and fantail populations also recovered dramatically, with chick survival increasing from 10 percent to 48 percent.
Relatively few birds have died as a result of 1080 operations, and these losses are quickly outweighed by the boost to populations once the threat of predators is removed.
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