“Quiet forest” claims are dispelled by bioacoustics study of 1080 effects

The use of the toxin sodium monofluoroacetate (otherwise known as 1080) for possum eradication has long raised concerns that a heavy toll is being taken on wildlife and the environment.

The Department of Conservation – supported by farm organisations among others – says it is the most suitable poison for aerial drops to kill possums which are destroying native bush. Destroying possums limits the spread of tuberculosis from the pests to livestock on farms.

But 1080’s critics say the poison kills not only pests, but also native birds and wildlife such as kiwi. Moreover, it is a cruel method of pest control and may contaminate the ground and waterways.

On  Radio New Zealand’s Nine to Noon programme this morning, Roald Bomans told of studies to investigate the claim that aerial 1080 drops cause forests to fall silent.

He used bioacoustics, a developing area in ecology, to monitor native bird species in the Remutaka and Aorangi Ranges.

He did this by listening to recordings and developing a special detector for morepork calls.

Collectively his bioacoustic monitoring showed no negative impact on the populations of native bird species.

The interview can be heard HERE.

It follows a seminar led by Roald Bomans at Victoria University last month.

According to his notes on the university website (HERE) about the seminar :

I used recordings from autonomous recording units (ARUs) to monitor resident bird species over multiple aerial 1080 operations in order to investigate this claim.

The total amount of birdsong recorded did not decrease significantly in treatment areas relative to non-treatment areas. The calling prevalence of one species, the introduced chaffinch (

Diurnal monitoring was conducted for 10-12 weeks over two independent operations. The total amount of birdsong recorded did not decrease significantly in treatment areas relative to non-treatment areas. The calling prevalence of one species, the introduced chaffinch (Fringilla coelebs), showed a significant decline in the treatment area across one of the two operations monitored. Collectively, these results suggested no negative impact of modern 1080 operations on the populations of native bird species.

Extracting data from ARU recordings can be labour intensive.

In the second part of my study I developed a process for developing a parsimonious template-based detector in an efficient, objective manner and applied this method to the creation of a detector for morepork (Ninox novaeseelandiae) calls.  The method was highly successful as a directed means to achieve parsimony. In independent validation tests, the final detector had a high precision (0.939) and moderate sensitivity (0.399).

This detector was used to monitor morepork in treatment and non-treatment areas across three independent aerial 1080 operations. Morepork showed no significant difference in trends of calling prevalence across the three operations monitored. Over a longer time period, a significant quadratic effect of time since 1080 treatment was found, with calling prevalences predicted to increase for 3.5 years following treatment.

Collectively, the results suggest a net-positive effect of modern 1080 mammal control on morepork populations.





DOC critic says loss of science quality in NZ is having dire consequences

The scientific justifications for the use of 1080 poison have been challenged in an article posted online (HERE) by Dr Jo Pollard, whose CV includes 18 years conducting research on animal management with AgResearch.

Back in the 1990s, she recalls, any hint of a prejudicial bias seriously undermined a scientist’s credibility but nowadays (she says) it seemed a scientist’s selling ability mattered most.

She contends:

“Gaining funding and successfully delivering results that generate more funding is vital to career development. And since the NZ government controls the money (grants to universities, NGOs and its own departments) the government gets and selects what it wants.”

The Government wants and since the 1960s has been getting widespread aerial poisoning with 1080, Dr Pollard says.

“The government has argued it needs to kill introduced mammals claimed to spread bovine tuberculosis (Tb) and threaten native wildlife, and widespread poisoning is the best way.

“Respected scientists are expected to sit tight while the media, government departments and high ranking officials misuse data to suit pre-ordained agendas.”

One example cited by Dr Pollard is the claim by the Parliamentary Commissioner for the Environment, Dr Jan Wright, that 1080 poison is “moderately humane”.

But her focus is on the kea, which she claims is a victim of “New Zealand’s degraded science culture” which

“…has spawned the rise of some disease-busting and biodiversity-conserving specialists whose claims go unchallenged, have a very strong following and who are supporting ever-increasing poisoning campaigns”.

Dr Pollard challenges claims that 1080 is needed to kill stoats.

She refers readers to http://1080science.co.nz/scientific-reviews-of-1080/

The use of 1080 by DOC was the subject of Dr Pollard’s criticism in 2011 HERE and HERE

The DOC response (HERE) was written by Paul Livingstone, manager of TB eradication and research at the Animal Health Board, and Mike Slater, Conservator for DOC on the West Coast.

They said:

Although birds, invertebrates and other animals are certainly not immune to the poison, the risks are greatly mitigated by the lethal doses they need to consume. There is no evidence that the toxin has a cumulative effect, or persists in the food chain. In fact, one of the most remarkable properties of the toxin is how quickly a sub-lethal dose is metabolised and expelled from the body. The risks to non-target species are further alleviated by the extremely strict regulations around how the toxin is used. For example, decades of extensive research and operational experience have enabled us to improve the efficiency and minimise the risks of aerial 1080 operations through:

• A reduction in the average quantity of poison bait used per hectare from 30kg/ha in the 1970s to just 2kg/ha today
• Research into more efficient dispersal methods, such as cluster sowing, that may further reduce the quantity of bait used by up to 75 per cent
• The use of GPS technology to make the deployment of baits accurate to within a couple of metres
• The routine use of cinnamon lure to attract possums and repel birds
• The routine use of carefully-screened cereal baits

The response also noted the Environmental Risk Management Authority, in a reassessment of 1080, had concluded the benefits of using 1080 to control introduced species that are destroying our endemic wildlife and spreading bovine TB outweigh the adverse effects.

Dr Pollard is qualified at Honours level in ecology (Limnology, Ecology and Applied Ecology) and animal behaviour and has particular interests in animal welfare, NZ’s ecology, and scientific integrity.

Another rejoinder from DOC seems inevitable.