Unfortunately, there is more. A letter was delivered to DOC's New Plymouth office with a blue substance leaking out it, and a South Island DOC worker's details were published online with comments about filling him with lead, and needing good snipers in New Zealand.
The Prime Minister, Conservation Minister and Agriculture Minister have all become targets in a fanaticism that borders on overseas terrorism.
During the past two years, DOC has spent about $780,000 on security for aerial 1080 drops. During October and November it spent another $295,000 on a co-ordinated incident management (CIM) plan in response to an increase in threats and abuse.
Add to that all the other local costs, money which should be going towards conservation itself.
One pest control company also reported its staff had been the target of many threats and of vandalism. In Northland, people had broken into its equipment and let 2000 litres of helicopter fuel out into native bush.
It was in November 2014 that Jeremy Hamish Kerr mixed highly concentrated amounts of the poison with baby milk formula and posted them to Fonterra and to Federated Farmers, with a letter demanding the country stop using 1080 or he would release poisoned infant milk powder into the Chinese market and one unspecified market.
The crime cost the country, the High Court was told, more than $37million, and Kerr was jailed for eight and a half years in 2016.
In September, a hikoi of protesters arrived at Parliament and threw fake 1080 pellets and dumped dead birds on the steps.
An organiser said: ''We wouldn't throw 1080 around and endanger the public like our government does. So we put fake 1080 on the steps, and dead bodies that have been killed, dead birds and mice that have been killed by 1080, brought here from the West Coast to present to these politicians.'' It transpired none had been killed by 1080 and one, a weka, had been shot.
There is no doubt dogs are at risk from eating carcasses after 1080 drops, and this underlies the emotion of many in the anti-1080 camp. Deer also suffer and hunters can have interests which conflict with 1080 use.
The abuse and the trouble escalated at the time of the hikoi and its related protests, although organisers always said their actions were nothing but peaceful.
What is to be done, though, about the fanatics who go far too far?
First, the police and courts have to be firm and no-nonsense with this criminality. It must not, and cannot, be tolerated.
Second, others also anti-1080 emphatically have to give no support to the threats and vandalism. Whatever their feelings, they should denounce such behaviour without qualification - for the sake of any credibility of their cause, if nothing else.
Third, any members of the public with interest in these matters could read and research on the benefits of 1080 and on its risks and downsides.
That means ignoring the emotive and misleading cries and misinformation from the protest groups.
Listen to those who really care about saving our forests and our birds. Know that they recognise that use of the poison 1080 is - at least for now - the only reason many forests are alive with bird song.
