Page 3 – Controlling rabbits with poison
Station owners and farmers tried a variety of measures to combat rabbits. At first they relied on the traditional methods of digging out burrows, hunting with dogs, shooting and trapping. Large gangs of men were employed, but were unable to cope with the vast numbers of rabbits.
Phosphorus and grain
Captain J. W. Raymond, who held Avondale Station in Southland, developed a recipe for poisoning wheat and oats with phosphorus. This became the favoured means for controlling rabbits in the 1880s and early 1890s. However, rabbits would not take the poison if grass was available, so it could only be used successfully in winter.
Phosphorised pollard (wheat bran), which was introduced from Australia in the mid-1890s, proved more palatable and rabbits took it year-round. Unfortunately stock also took the bait readily, so rabbiters had to be careful where they laid it. Despite that, phosphorised pollard was the most widely used measure of rabbit control in Otago and Southland by the end of the 1890s.
In a jam
Professional rabbiter W. H. McLean recalled a rabbit inspector telling him about a new type of bait in the 1930s:
‘D’you know they’re using jam as bait in the South Island? It started when a rabbiter heard a noise outside his camp one night; when he investigated he saw rabbits licking out jam tins. So he tried it as a bait and it worked. They like apple and raspberry jam best. Quince, too, but that’s a bit dear.’ 1
A range of proprietary poisons were marketed. Perhaps the most successful was Toxa. It required no mixing, it was easy to lay and rabbits took it readily. However, it was more expensive than other poisons. A variety of other options were also tried: arsenic and chaff, arsenic and grain, strychnine and apples or carrots, and strychnine and jam. The last was popular as it was easy to transport to hill country.
Rabbit burrows were also gassed with bisulphide of carbon. This was most effective in heavier soils, as the gas tended to dissipate in light or sandy country. There are reports of gas being used as early as 1879, but it did not become widespread until the early 20th century, when machines were invented to pump gas or to spray the liquid bisulphide directly into burrows.
Aerial poisoning and 1080
There was a major breakthrough in large-scale rabbit control after the Second World War. In 1949, experiments in dropping poisoned bait from fixed-wing aircraft proved successful. Remote and inaccessible areas, particularly in the South Island high country, could now be included in large-scale poisoning programmes.
In 1954 a trial found that sodium monofluoroacetate (1080) was more effective than other poisons previously used. By 1960 it had become the main poison used in rabbit control. The combination of aerial spreading and the use of carrots poisoned with 1080 enabled rabbit boards (which were responsible for rabbit destruction work) to reduce rabbit numbers in most areas by the early 1960s.