Tag Archives: Marlborough Sounds

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, News

Dropping 1080 on trampers – the 2013 Marlborough incident you possibly didn’t hear about

June 3, 2017 Pam Vernon Leave a comment

From Carol Sawyer

FIRST A 1080 POISON BUCKET IS DROPPED, AND NEXT PELLETS ARE RAINED ON TRAMPERS, IN A ‘MARLBOROUGH HELICOPTERS LTD’ DOUBLE-WHAMMY COCKUP!

This bungled 1080 drop on Mt Stanley/ Tennyson Inlet, Marlborough Sounds on 2 November 2013, may be three and a half years ago, but how many people know about it?

I have been sent two reports in the post, that give a bit more background.

1 ) “Investigation into uncommanded bucket release” by John Sinclair, NZ AAA and NZ Helicopter Assn, Occurrence Investigator

2 ) “Notes on Aerial 1080 drop 2/11/2013, Mt Stanley, Tennyson Inlet” by Phil Clerke, senior biodiversity ranger, Dept of Conservation, Picton

These two reports make for fascinating reading.

This drop was conducted by Marlborough Helicopters Ltd for the Dept of Conservation. Two pilots were involved, flying two Bell Jetrangers, ZK-HJI and ZK-HZE. The senior of the two pilots was a director of the helicopter company. The other pilot was completing only his second poison drop, “but he had considerable experience in other aerial agricultural operations and is a competent pilot with sufficient experience to undertake poison drops” Occurrence Investigator, John Sinclair said.

I shall call them Pilot One and Pilot Two.

According to the report by DoC’s Phil Clerke, Pilot One left the barge to commence his baiting, but arrived back “somewhat shaken” and minus his bucket. He had ” visibly received an impact above the eye ( I was later to learn it was from the breaking airline leading to the bucket ). I was unsure of the exact details but picked up that the bucket’s airline then struck the rotors as well. I later learned that (Pilot One) also lost partial sight in this eye.”

This report differs slightly from the Occurrence Investigator, John Sinclair’s, report which says

” …….(Pilot One) was carrying out a trickle feed of sensitive boundaries when the bucket and its load of 1080 suffered an uncommanded release from the helicopter. In the departure sequence a pneumatic control line severed and flicked up cutting the pilot’s eye”. Also the “pneumatic control line had connected with the OAT and cracked the windscreen”.

Despite this injury, Pilot One flew himself to Blenheim and came back in an R22 with a long lifting chain, after which Pilot Two went off (with the chain presumably) to recover the dropped bucket! Once this was done, Pilot One returned to Blenheim in the R22.

John Sinclair’s report has a great deal of detail about the bucket release, but he says

“I believe that the most likely cause of the uncommanded release of the cargo hook was the helicopter’s manual cargo hook release being activated, then not properly returned to the safe position before it was next used” (Human error, in other words).

Because of all this dropped bucket palaver, this meant that the less experienced pilot, Pilot Two, had to complete the sensitive boundaries – instead of now-injured & more experienced Pilot One, the one who was supposed to be doing it. John Sinclair’s report reads :

“In the course of doing this Pilot Two misjudged conditions and allowed the wind to carry a small amount of bait onto the Nydia Bay Track. Pilot Two was under considerable pressure because of the need to do another drop the next day in Golden Bay. While DoC had offered to postpone the operation there would be the logistics of barging all the bait back to Picton if the operation was curtailed. These pressures may have impacted on his subconscious, especially given that the weather windows this spring have been very few and far between.”

The bait falling “onto the Nydia Bay Track” unfortunately appears to have fallen on the trampers mentioned in the article below.
In the Occurrence Investigator John Sinclair’s report, he just refers to it thus:

“The dropping of the bucket did however impact on an adverse environmental effect later in the day”. ( The adverse environmental effect being presumably, dropping 1080 pellets on trampers.)
In the DoC report, Phil Clerke says a DoC worker, Wendy, “radioed in to pass on that she had met trampers that claimed they were rained on, on the track at the saddle”.

The trampers, incidentally, knew of the 1080 drop but had been told the track itself was SAFE as it had an exclusion zone of 20 metres.

Some questions I have are these :

1 ) Why did Pilot One fly a helicopter back to Blenheim and collect another one, when it had a cracked windscreen and he had a cut on his eye ! Not only that but he returned with another helicopter !

2 ) Why was a pilot who had only done one 1080 drop before, allowed to fly the sensitive boundaries, when as well as this the wind had got up – Phil Clerke says “the wind was noted to increase in velocity, Pilot Two and I had a discussion about this. It was still considered workable.” So pellets land on trampers!

3 ) This question should be asked of DoC : Why on earth was 1080 poison loaded onto helicopters off a barge in pristine Tennyson Inlet? The DoC report says, “A vacuum cleaner, dust brushes/ pans were to be used with the initial barge clean up to reduce wash down contamination. Wash down would only be used when no further bait fragments could be recovered.” (Meaning 1080 dust would be washed into Tennyson Inlet, presumably!)

Carol Sawyer

Here is the stuff.co.nz report on this incident:

Trampers Want an Apology after Pellets Rained Down

Two trampers want an apology from Conservation Minister Nick Smith after the area around them was showered with 1080 pellets as they walked the Nydia Track in the Marlborough Sounds.

Simon and Carol Caley had set out from Duncan Bay on Saturday when they saw a 1080 warning sign and met a DOC employee who assured them helicopters would not drop pellets within 20 metres of the track.

Near the high point of the walk at Nydia Saddle, Mrs Caley heard pellets dropping through the trees and one just missed her foot. She said she felt dust on her face and neck, had an appalling taste in her mouth and breathed in a strong smell of cinnamon.

For further articles on 1080 use ‘categories’ or the search box. And see our 1080 pages for further links to more information.

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