Cruel poisons won’t return birdsong
Fiona McQueen responds to a recent opinion article decrying those who challenge the use of 1080.
Dave Hansford has launched yet another attack against those opposed to pest control in the Brook Waimarama Sanctuary, near Nelson. This sanctuary has just reopened, surrounded by a 14km pest-proof fence. It will be stocked with kiwi, ka¯ ka¯ riki and ka¯ ka¯ .
The nasty part is that brodifacoum, a poison graded 8/10 for its ability to cause animal suffering, needed to be introduced first to kill pests inside the fence. It also killed native birds including weka and pukeko.
Do the ends justify the means? A human equivalent would be if a ruling party decided to exterminate all unwanted people and restock with different people who are representatives of a ‘‘chosen race’’. Wait a minute, hasn’t that been done before?
Andrea Midgen, chief executive of the SPCA, recently spoke out about the associated animal cruelty, saying, ‘‘1080 (and other poisons) causes intense, prolonged suffering to animals and therefore we cannot support its use’’.
Suffering is not mentioned to those who enjoy our ecosanctuaries. Should it be?
Hansford then segues into a tirade against protesters who oppose the dropping of 1080 over vast swaths of native forest (about 1000 tonnes annually, 80 per cent of total world production).
He skims over the fact that these areas of native bush do not have predator-proof fences. Consequently, after 1080 has cleared all the rats and native fauna (yes, it can definitely kill an array of native birds, insects and aquatic life), the forest remains very quiet for a while.
But nature abhors a vacuum and the place is repopulated from the edges by those that reproduce rapidly, producing
post-1080 rat plagues.
One publication showed rat numbers bouncing back to more than double their baseline levels,
12 months after a 1080 drop. These are young, active rats, hungry for native birds.
What about the evidence then that 1080 boosts bird populations? Does it really ‘‘bring back the birdsong’’?
That depends on who you believe. Kea are at high risk of death by 1080, because they are naturally curious and attracted to baits. Of the 150 kea that have been formally monitored, 12 per cent died of 1080 poisoning (found in their stomachs and muscle tissue). Tomtits, robins, morepork and fernbirds have all been proven to have died 1080 deaths and there are accounts of tu¯ ı¯, wood pigeons and even kiwi found dead on the ground after poisoning operations.
Deaths in non-target species (including birds such as the American eagle) was one of the reasons the Environmental Protection Agency banned 1080 from widespread use in the United States in 1985.
The ko¯ kako has been held up as the ‘‘poster-bird’’ of 1080’s success. Its numbers trebled after eight years of pest control in Mapara, near Te Kuiti, according to a 1999 study. But there were scientific flaws in that study. Mapara has a unique geography, being an ‘‘island of forest in a sea of pasture’’, which might deter recolonisation by rats (the Achilles heel of all poisoning operations).
It could not meaningfully be compared with control areas. The increase in bird numbers was largely due to brodifacoum, not 1080, but that poison is kept in DOC’s back cupboard as it is not only ugly in terms of animal suffering but very slow to degrade.
Dr Quinn Whiting-O’Keefe, a clinical trials specialist, said: ‘‘The principles of good research design are well established, and . . . have not been followed by DOC in the research supporting their assertions on the use of aerial 1080 . . . If healthcare used this standard of evidence, we would likely still be bleeding patients as a cure for pneumonia.’’
What about TB? Hansford raises the spectre of hordes of tuberculous possums pouring down to infect innocent dairy cows as they graze in their paddocks. The reality is rather different. New Zealand is regarded internationally as ‘‘TBfree’’, that is < 0.2 per cent of our dairy herds are infected by bovine TB. Actually our level is < 0.003 per cent.
Evidence for possum-to-cow transfer of TB is flimsy at best and this can be prevented by simple trapping at the edges of paddocks. Many farmers argue that bovine TB is most often transferred from other infected cows. This can be minimised by good farming practices.
What are the alternatives to aerial 1080? We could stimulate the fur trade and reduce damage to forests by trapping possums. Multi-use traps have also been developed for rats. The new CRISPR gene-drive technology could eliminate rats but this prospect has been ominously described as ‘‘extinction on demand’’; and is a dangerous path for ethical and biological reasons.
Perhaps it is time for us to ‘‘step away from the ecosystem’’. The fledgling science of invasion biology indicates that nature has its own ways of exerting control over species that proliferate too much. Some human elders remember a time before 1080 when there were more native birds in the bush. Let’s listen to what they have to say. Poisoning can only do harm.