The predators behind NZ’s conservation
Stoats, ferrets and weasels (and cats, for that matter), were well regarded by land or run holders from the mid 1800s as a "natural" remedy for the rabbit menace.
We can now look back with the benefit of 150 years of hindsight. It’s easy to shake your head, in the glib comfort of 21st century knowledge and condemn these people as short-sighted.
The introduction of stoats, ferrets and weasels was part of a number of environmental catastrophes in early New Zealand history. It set in motion a wave of conservation sentiment, resulting in the reserve areas and public conservation land that we recognise today.
Oddly, stoats, ferrets and weasels contributed to that outcome. Many liberations of these animals were made by run holders as part of an all-out war against the wave of rabbits sweeping the country.
Syndicates of run holders formed to import mustelids (stoats, ferrets and weasels), which were carefully nourished on a diet of biscuit, milk and a little meat, before being released into the wild.
Opinion varied on the suitability of different mustelid species for different parts of the country. In Otago, the stoat and weasel were favoured and the ferret regarded as a failure. But in Canterbury and Marlborough the ferret found favour.
There was ongoing debate about the suitability of each species. In Kaikoura, run holder Mr Bullen claimed excellent success on Green Hills Station in the late 1800s, with rabbits practically eliminated (he claimed) by the use of weasels and ferrets. St Helens got its sheep carrying capacity back up to 50,000, from a low of 20,000, after the successful introduction of mustelids. Molesworth and Tarndale also benefited, it was claimed, from a similar release.
The apparent success of mustelids in reducing rabbits encouraged a group of Canterbury and Marlborough run holders - Trelove, Murray, Thomas, Rutherford and Parsons - to fund further liberations, reported the Evening Post in 1905.
At the time there was doubt being cast on the ability, particularly of the ferret, to successfully breed once released into the wild. Consternation surrounded the great mortality of ferrets released from captivity. Claims also were made of a person walking on a property shortly after the liberation of ferrets, only to be surprised by something clutching at his boot, which turned out to be "a ferret in the last stage of starvation, seeking for human pity and succour!"
There was considerable money put into obtaining mustelids, so their success needed to be assured. One group spent £2500 importing a batch of ferrets from England, with an equal amount stumped up by the Government of the day, by way of a subsidy.
But by this time, there was already a level of disquiet being voiced about the wisdom of releasing mustelids into the wild. These dissenters were mainly settlers concerned about the impact of mustelids on their chickens, or sportsmen worried about the impact on game hunting.
Pressure was growing to recognise the wider impacts of mustelids, plus change the legal protective status of these animals. Parliamentarians, such as the member for Waikouaiti, Mr Thomas McKenzie, started voicing concerns about the effects and impacts of mustelids on the wider environment. In this he proved prophetic.
In reply to a question from the Evening Post in 1905, he said, ‘‘one cannot but deplore the necessity for the liberation of such vermin in this country, and they may have been liberated in many instances where they are not required at all. Years ago on the western side of Lakes Te Anau and Manapouri, where the country will never be required for sheep or cattle, but where at that time our choicest and rarest native game abounded, these vile brutes were rowed across the lake and let loose. All our native game, I think, will suffer; and if the Government permit the shooting of our birds at the same time that the natural enemy is destroying them, I fear within a short time all our most charming birds will disappear’’.
There was certainly a realisation growing in New Zealand at the time that our native species were under serious threat, one of these threats being the introduction of predators such as mustelids.
Conservation thinking was not mainstream, but it was starting to gain traction. Botanist Leonard Cockayne and politician Harry Ell were prominent supporters of conservation initiatives at this time.
This shift in thinking was slowly gaining results with the formation of reserves from the late 1800s. Flora and fauna reserves were created on off-shore islands such as Resolution Island (1891), Secretary Island (1893), Little Barrier Island (1895) and Kapiti Island (1897).
By 1903 the Scenery Preservation Act had been passed. This was New Zealand’s first legislation aimed at protecting sites of scenic and historic interest.
This was partially in recognition that tourism could potentially become a lucrative part of the NZ economy. But the Act allowed scenic, scientific, historic and "natural curiosity" values to be the basis of forming reserves.
A Scenery Preservation Commission travelled the length of New Zealand, recommending areas to set aside as reserves. The commission struggled in the face of opposition from private land owner interests,but laid the path for the future of the New Zealand reserve network.
Ironically then, the depredations of rabbits, and in turn mustelids, actually helped stimulate a climate for a burgeoning move towards conservation in NZ by the late 1800s.
Public enemies of the pest kind. A weasel, left, ferret, rear and stoat.