Cereal baits now have cinnamon oil added to attract possums but repel birds. They are also dyed a bluish-green — green to camouflage the bait with just enough blue to discourage birds, who prefer red or yellow-coloured food items.
Deer repellent can also be added. Non-toxic baits are spread prior to an aerial operation. Pests, especially possums, nibble the new food, find it safe to eat and then seek out the poisoned bait when it is dropped a few days later.
This results in a more successful kill rate and means longer times between operations. Fewer baits per hectare mean that non-target species are less likely to come in contact with a bait. Technology has also helped to limit risk to non-target species.
Aircraft now use GPS to ensure the accuracy of the application. GPS track lines and boundaries show pilots exactly where to fly. The systems also record flight movements to the nearest metre and where bait buckets are opened and closed. The Department of Conservation DOC notes that is far less toxic to birds than mammals, but some native birds — weka, robins, tomtits and kea — are susceptible. Kea that live near ski fields or huts regard many things as food — they are curious, and often get handouts from humans.
DOC is testing kea repellents, and care is taken to avoid placing baits above the tree line on mountains. For some species — the kiwis, riflemen, mohua, morepork, kaka and long-tailed bats — the results are very straight-forward: no animals are killed by the poison and productivity and survivorship goes up following use.
The term has long been a bit of a dirty word among a subset of New Zealanders. I've often wondered whether if it had a nicer name, people would be so quick to react to it.
What if it was called "Pest-rid" or "Wildlife rehabilitator" or something far more creative? Trying to have a rational conversation about the use of in New Zealand is like trying to negotiate bedtimes with a toddler. Dr Wright raises some good points about why communities get upset about the use of - in particular she says , "The idea of dropping poison out of the sky just gives you a bad feeling To people in areas who feel fearful about this, it seems no amount of scientific evidence, or GPS tracking of operation helicopter grid lines, will ease their minds.
But the facts do provide reassurance if people are willing to accept them. The problem with the debate is that the level of frustration on both sides leads to problems trying to communicate with one other on what's really going on out there.
I reckon it's time for a truly honest discussion about the use of this toxin, and that means all sides of the debate. I have long been a proponent of the use of to protect our native wildlife in New Zealand.
To begin, I thought I'd offer some of the basics on As an aside, we used to have three species of bat, but a rat plague on Great South Cape Island in the s wiped the greater short-tailed bat off the planet. There have been more than independent tests of waterways after drops.
The level for detection set by the Ministry of Health is two parts per billion. This has never been breached in drinking water supplies, but if it was, a person my size would have to drink 60, litres of water in one sitting in order for it to affect me. As a side note, the biggest cause of death for kea on the West Coast is predators - estimated to take out 60 per cent of kea nests eggs, chicks, even parents in areas without pest control.
Today's operations largely use hard cereal baits. Silent forests. Many opponents of claim that they have been into the bush after a drop, and the forest is silent, due to having apparently killed all the native birds. This is one of those native wildlife myths that drives me mad. The forests are silent because of predators.
Every single night, we are losing the very creatures that define us as a country. Even in these areas, well-managed trapping and ground baiting operations can be overwhelmed by natural events such as beech seed masting events which lead to huge increases in predator numbers. About five percent of the estate is treated with in a normal year.
Masts lead to a dramatic increase in the numbers of rats and the stoats that prey on them. When the supply of seeds declines, predators target native birds instead.
With the limited resources available for Battle for Our Birds, DOC had to prioritise areas to receive predator control. This meant many areas where predator numbers exploded during the masts did not receive any control and native bird populations fell as a result. The Parliamentary Commissioner for the Environment, Dr. Jan Wright, found in her evaluation of that we should be using more to save our forests and the wildlife that lives in them.
The main use of is in baits that are designed for consumption by possums and rats. Most baits used in aerial application in public conservation forests are cereal baits dyed green to discourage birds from eating them. GPS systems ensure baits are distributed very accurately from the air.
Since the s, the average quantity of bait used in forests has dropped from 40kg a hectare to less than 2kg for cereal baits — the equivalent of four baits in an area the size of a tennis court. When correctly applied, is very effective. However, birds and other native species can benefit greatly from having one or two good breeding seasons without large-scale predation by rats. Trials in streams showed 90 percent of was leached from baits within 24 hours.
Monitoring of public water supplies has never shown contamination by In soil, can break down in one to two weeks in warm moist conditions, although it can sometimes take several months in extremely dry and cold conditions.
Most operations are done in wet winter or spring conditions which encourages the rapid breakdown of the baits. Read the reassessment and approval to use We have the legal authority to grant permission to use and other animal poisons called vertebrate toxic agents under section 95A of the HSNO Act.
When is used in an area where there is drinking water or where there may be a risk to public health, the power to grant permissions is delegated to medical officers of health and health protection officers, who are employed by district health boards.
They can set extra terms and conditions depending on where and how is being used and may also consult with the public before deciding whether to give permission to use The Ministry of Health and DOC can audit the permissions they issue to make sure operators have followed the conditions of their permissions.
We also carry out audits to monitor how these organisations are using their delegated powers. Anyone handling must have a controlled substance licence, and hold a certified handler certificate.
They must demonstrate they have followed the rules for use. This is a requirement under the HSW Act. The rules include:. All our decisions, including the decision to allow the use of , are expected to be transparent and open to public scrutiny and discussion. These include a requirement for all operators carrying out aerial pest control operations to provide reports for all activity, with details of every operation.
The report must include any incidents, such as bait that was lost, spilled or misapplied during an operation. The reports are required to be submitted to us as soon as reasonably practicable, but no later than six months after the operation. We publish the reports as soon as possible after receiving them. EPA Annual reports on aerial operations. Anyone who has in their workplace must provide WorkSafe with an annual report. It must include the name of the supplier who supplied the , what is was used for and whether it was moved or disposed of.
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