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There’s an Even Worse Poison than 1080 – It’s Brodifacoum

December 30, 2025 Pam Vernon 4 Comments

This article was originally published here in 2023 … EWNZ

“The Ministry of Primary Industries stipulates a withholding period of 4 months for 1080 poison. For brodifacoum it is 3 years i.e. 36 months after poisoning.“

by Tony Orman

Government use of 1080 poison in New Zealand is controversial and seems to command the headlines ahead of other poisons.

But there is a much worse poison – it is called brodifacoum.

Brodifacoum is widely used by regional councils and government agencies such as the Department of Conservation. Typical of its widespread use is Ulva Island near Stewart Island where the Department of Conservation is currently undertaking rodent eradication.

I have come across brodifacoum poisoning notices in the central North Island when trout fishing, accompanied by my Labrador dog. In one case I asked a farmer why the regional council was using brodifacoum for possums. He didn’t know and added that possum numbers were very light anyhow.

Because of the extreme danger to my dog, I didn’t go fishing. Besides, trout fishing a river into whichever toxic baits will have fallen or on the banks, doesn’t make for an enjoyable day’s fishing!

Such cavalier attitude of regional councils – and the Department of Conservation – belies the lethal nature of brodifacoum.

Comparison

How does it compare to 1080?

Both poisons have a ”withholding period” which means a time must elapse after the toxin’s use before stock can be safely grazed or game animals such as deer, taken for home consumption.

The Ministry of Primary Industries stipulates 4 months for 1080 poison. For brodifacoum it is 3 years i.e. 36 months after poisoning.

The extensive withholding time for brodifacoum is due to its known long-term persistence in the environment and animal bodies.

**Brodifacoum warning notices by a King Country trout stream – photo Tony Orman**

What is brodifacoum?

Brodifacoum is an anticoagulant, which causes the animal to die slowly and painfully from internal bleeding. As cruel as death over two or three days is by 1080, by brodifacoum it is far more prolonged, in the case of rats within 4 to 8 days and larger animals such as possums, up to 21 days.

1080 requires a user to have a licence to use the toxin but no licence is needed for brodifacoum, for example rat poison sold over shop counters, to anyone, young or adult with no controls whatsoever.

Secondary Poisoning

Brodifacoum and 1080 have another similarity, called “secondary poisoning”. In other words a dead poisoned animal remains toxic and any bird or other creature scavenging the dead body, takes in poison and dies.

Scientists C.T. Eason and E.B. Spurr in 1995 in a study “The Toxicity and Sub-lethal Effects of Brodifacoum said insectivorous birds (e.g. bush robins, fantails) are likely to be exposed to brodifacoum by eating invertebrates that have fed on toxic baits; i.e., they are likely to be at risk from secondary poisoning. Predatory birds (especially the Australasian harrier, New Zealand falcon, and morepork) might also be at risk from secondary poisoning by eating birds, small mammals, or invertebrates that have fed on toxic baits.

Predators are greatly at risk. Both poisons are very slow to kill, and especially so with brodifacoum. An animal be mouse, bird or insect, on taking the poison, slowly dies and in its distressed, weakening state, naturally and quickly attracts the attention of predators among them native birds such as bush falcons, hawks, moreporks, pukekos and wekas.

**Bush robins are at risk from brodifacoum – photo Tony Orman**

Ecological history is littered with instances following poisoning. For example scientists Eason and Spurr said the “entire weka population on Tawhitinui Island, Pelorus Sound, Marlborough Sounds was exterminated mainly by direct consumption of rat bait (Talon) intended for ship rat control.”

The two scientists said “indigenous New Zealand vertebrates most at risk from feeding directly on cereal-based baits containing brodifacoum are those species that are naturally inquisitive and have an omnivorous diet (birds such as weka, kaka, kea, and robins). The greatest risk of secondary poisoning is to predatory and scavenging birds (especially the Australasian harrier, New Zealand falcon, southern black-backed gull, morepork, and weka)”

The duo added “the risk from brodifacoum will be at its greatest when saturation baiting techniques, such as aerial sowing, are used in eradication programmes.” Such as Ulva Island where DoC is “aerially sowing” brodifacoum.

Seven years later in 2002, Spurr and Eason along with two other scientists produced a study “Assessment of risks of brodifacoum to non-target birds and mammals in New Zealand”.

The quartet of scientists described brodifacoum as “highly toxic to birds and mammals” and listed victims such as the Australasian harrier (Circus approximans) and morepork (Ninox novaeseelandiae), other native birds such as the pukeko (Porphyrio melanomas), weka (Gallirallus australis), southern black-backed gull (Larus dominicanus), and kiwi (Apteryx spp.) and introduced mammals, including game animals e.g. deer.

Dead Dotterels

Other studies have identified the lethal nature of brodifacoum.

Landcare Research scientist Penny Fisher said “because brodifacoum persists in the environment, other birds may suffer secondary poisoning from eating animals that have ingested poison” and cited “a high mortality of New Zealand dotterels following an aerial brodifacoum operation at Tawharanui Regional Park in North Auckland, in 2004. At least 50% of the dotterels in the area at time of operation disappeared or were found dead. Sand-hoppers-common food item of NZ dotterels —ate baits and accumulated brodifacoum and provided a potential route for transmission of the toxin to dotterels.”

Two dead eels found in a Southland waterway had brodifacoum in the gut contents of one and that “suggests the eel had recently ingested food containing brodifacoum, probably through scavenging the carcass of a poisoned possum.”

Freshwater Residues

Brodifacoum similar to 1080, leaves residues.

In 2005 a paper in the New Zealand Journal of Marine and Freshwater Research, Volume 39, told of freshwater crayfish (koura) with significant 1080 concentrations and 1080 residues in eel tissue that were on average 12 times higher than the PMAV (provisional maximum acceptable level).

The INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY Health and Safety Guide No. 93 said of brodifacoum “as a technical material — is highly toxic for fish”.

Processing poisons for wild animal control/eradication is Orillion a State Owned Enterprise governed through a Board of Directors appointed by the New Zealand Government. Orillion’s safety data sheet for brodifacoum says “may cause long lasting harmful effects to aquatic life.”

Therein lies a threat to not only valued sports fishes such as trout and juvenile salmon migrating downstream to sea, but also native fish such as eels and galaxids.

Sodium fluoroacetate, also known as compound 1080, is the poison around which controversy swirls. Brodifacoum is little known but is surreptitiously used by the Department of Conservation and councils.

1080 is ecologically destructive and damaging to the ecosystem – but brodifacoum is far worse.

Footnote: Environmentalist Tony Orman has spent a lifetime in the outdoors and has had some two dozen books published among them “New Zealand the Beautiful Wilderness”

Brodifacoum Worse Poison than 1080

Header Photo: Wikipedia – By Squidonius – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=17253187

1080, DOC, News, Poison

DoC sows 1080 bait on snow in spite of their Code of Practice saying not to

June 10, 2018 Pam Vernon 1 Comment

THE TIMARU CREEK, LAKE HAWEA, 1080 DROP ZONE IS COVERED IN SNOW!

Thanks to Carol Sawyer, Clyde Graf and Ron Eddy for this information:

The 1080 poison is due to be aerially dropped within the next couple of weeks. Prefeed baits were dropped on May 28, 2018.

Here is why 1080 baits should not be dropped in snowy, wintry conditions. According to the information below, DoC’s 2014 Code of Practice suggests : “Avoid sowing toxic baits on snow. With regard to rocky outcrops, these should be evaluated along with other timing and boundary decisions in operational planning. Seek advice from technical and science advisors for your situation”.

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I received this email from Ron Eddy in March, 2017, re dropping 1080 in SNOW!:

“Now to 1080 in snow. …… at a meeting in St Arnaud where Josh Kemp, DoC’s Kea scientist was present Kemp answered my comment about dropping 1080 in snow. He replied “We never drop in snow.” I then pulled those photos out and silence reigned from the DoC side of the discussion. I think there was a drastic reduction in Nelson Lakes Kea after that 2008 drop because that was when they brought in the 2009 code of practice for 1080 operations in Kea habitat. That also brought in DoC’s Kea monitoring as the first operation shown on that chart is the 2008 Arawhata one. No mention of the Red Hills / Beeby’s / St Arnaud N Face or Upper Wairau ones though. In a reply to someone on the ‘net Kemp denied the Nelson Lakes NP area had had 1080 dropped on it at that time.
……..

About a week after the Upper Wairau operation into snow I went through an area of it and found 1080 baits that hadn’t been touched … they had blown up like sausages. 1080 lasts a lot longer in cold conditions, the cold keeps it viable and to me, those baits were still viable because the hard centres in them were still solid. They went ahead with that drop knowing we were in for a large drop of snow and to my mind they were wanting to get every possum they could even though they knew there were very few possums there . Their monitoring told them so.

To have a deep blanket of snow also took away the food sources of our native birds. For them to see bright green coloured cereal baits on top of the snow would have been an open invitation to have free feed. Especially the Kea. That no doubt is also the reason DoC now diversionary feed Kea during 1080 drops in the Nelson Lakes NP area. That still didn’t stop one Kea that we know of from dying from 1080 poisoning in the 2014 operation.

In DoC’s revised 2014 “DOC code of practice for aerial 1080 operations in Kea habitat” on page 12 is a series of questions and answers in regard to aerial 1080 operations. Question 3 reads, ” We are planning to sow 0.15% 1080 Pellets in some open alpine areas to protect Rock Wren. What is the best timing to achieve this, considering that there could be snow for some of the year? Should rocky areas above the tussock be excluded?”

The answer is “Avoid sowing toxic baits on snow. With regard to rocky outcrops, these should be evaluated along with other timing and boundary decisions in operational planning. Seek advice from technical and science advisors for your situation.”

Apart from the directive in that answer I think the rest of the above info should give you a pretty good idea why 1080 baits shouldn’t be dropped on snow. Considering Rock Wren live in rock outcrops it appears their lack of knowledge on this subject contributed towards the demise of those 25 Kahurangi NP Rock Wren in 2014….. ” Ron Eddy, St Arnaud

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Clyde Graf said : “DoC dropped 1080 poison directly into snow in the Rainbow Skyfield area, St Arnaud – Nelson Lakes, back in 2008 I think it was. We filmed a bunch of poisoned birds laying on the snow, along with the baits. The poison is well preserved in snow, but these poisoning agencies are only about getting the poison dumped into the environment, not about what happens to it or where it ends up.” See photo above.

Photos :

1) Timaru Creek, Lake Hawea ( the last two mountains on the left are Corner Peak and Dingle Peak – then Timaru Creek comes out into Lake Hawea- then Breast Peak is basically that whole large range on the right ) – Photo Kirstin Dana 5 June, 2018

2 ) (Header) Dead birds found in snow beside 1080 baits, St Arnaud – Photo Clyde Graf, 2008