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A recent University of Otago study into the effects of a 1080 poison operation challenges claims about the negative impacts on native wildlife.
The on-going study, which is being conducted by scientists from the university’s Threatened Birds Research Group with some funding from the Animal Health Board (AHB), is investigating the effects of modern aerial 1080 methods on a marked population of native robins. Traditionally, studies have used the less-reliable ‘five-minute bird count’ method.
The research was carried out as part of a long-term study of a geographically-isolated South Island robin population in the Dunedin area. A total of 19 individually colour-banded robins were monitored in the Silver Peaks before and after 1080 was dropped, to see whether or not any birds were killed. A second study population of 15 marked robins in nearby Silverstream - where no 1080 was dropped - was also monitored over the same period for comparative purposes. Breeding success was also monitored at both sites.
“The AHB’s possum control operation in the Silver Peaks gave us a rare opportunity to study the effects of 1080 on an intensively-studied population of native birds,” said research supervisor, Associate Professor Ian Jamieson.
“We suspected that improvements in the quality of 1080 baits, together with big reduction in the amount of poison used would mean less impact on non-target species, but this hypothesis had not been tested using a marked population. We also wanted to see whether or not the current practice of pre-feeding with non-toxic pellets to overcome potential bait shyness in possums had any negative impact on birds.”
The researchers also monitored the number of possums and rats at the two sites, to determine how effective 1080 was at killing two of the robins’ major nest predators. The chew tracking cards used to monitor numbers at Silver Peaks showed no sign of either rats or possums 11 days after the operation or again after 80 days. By comparison, there was no real change at the non-treatment Silverstream site over the same period.
All banded birds in the Silver Peaks site were observed alive 16 days after the 1080 operation, and 67 per cent of monitored nests at the site successfully produced at least one fledgling. While all monitored birds in the control site were also re-sighted, breeding success was markedly lower, with only eight per cent of monitored nests successfully producing at least one fledgling.
“The conclusions we can draw from this data is that: Firstly, the pre-fed 1080 operation at Silver Peaks had no negative effect on the robins; Secondly, that it knocked the possum and rat numbers down to almost zero; And, thirdly, that robins’ experienced relatively high breeding success when predator numbers were low,” said Prof Jamieson.
“Gaps in the research around the effect of 1080 operations on native birds have been highlighted by both DOC and Forest & Bird,” said AHB research and TB eradication manager Paul Livingstone.
“We hope that this study helps to reassure people that aerial pest control operations using 1080 have genuinely changed for the better”.
Watch a short video of Ian Jamieson discussing the results and talking us through the research methodology (YouTube, 9 mins)
· South Island robins (Petroica australis) are protected endemic species. With the exception of a small population near Kaikoura, the robin population in Dunedin is the only one remaining on the east coast of the South Island.
· The Dunedin robin population has been studied closely since 2007 by the Threatened Birds Research Group.
· The AHB is controlling possums in the area around Dunedin to reduce the risk of bovine tuberculosis (TB) being transmitted from areas where the disease is endemic in the possum population into areas with no known TB. Scientific analysis links more than 70 per cent of new disease outbreaks in high-risk areas to wild animals, mostly possums.
· The AHB is charged with managing TB to maintain sustainable global market access for New Zealand’s beef, dairy and venison through livestock TB testing, strict movement controls and investment in possum and other pest control. These methods help maintain buffer zones which prevent infected wild animals from spreading into TB-free areas. Bovine TB will continue to be an issue for cattle and deer herds while it remains present in the wildlife population.
· The TBfree New Zealand programme has successfully reduced cattle and deer herd infection rates from 1700 in 1994 to fewer than 100 herds in June 2011.
· Aerially-applied 1080 is used on about 5-10 per cent of possum control areas. An operation can kill 98-100 per cent of possums in target areas and is highly effective in keeping numbers low enough to prevent the spread of tuberculosis within possum populations and onto farms. It remains the most effective method available to control possums in New Zealand’s notoriously rugged, steep and remote terrain.
· In June 2011, The Parliamentary Commissioner for the Environment’s report into the use of 1080 in New Zealand found it to be a safe and necessary tool, with a solid body of evidence supporting its continued use.