MACKENZIE COUNTRY FAILURE OF RABBIT FENCE

Press, Volume XC, Issue 27470, 2 October 1954, Page 9

MACKENZIE COUNTRY FAILURE OF RABBIT FENCE

New Methods Now Employed For Eradication POISON’S DISASTROUS EFFECT ON BIRD LIFE (Specially Written for “The Press”) (By W. VANCE) XVHI Caretakers could not cope with all the holes made in the fence built by the Government to prevent rabbits from crossing the Waitaki river from Otago into the Mackenzie Country. Flooded creeks gouged out the earth from under it; falling boulders battered it; shingle screes slipped away from it; rabbits burrowed beneath it. And rabbit population increased.

Caretakers could not cope with all the holes made in the fence; flooded creeks gouged out the earth from under it; falling boulders battered it; shingle screes slipped away from it; rabbits burrowed beneath it. And rabbit population increased. < By 1888 they had reached the ’’topmost portion of the Mount Cook pastoral country running on to the Tasman glacier. Rabbits soon found the warm country, their favourite haunts being sunny facings of Haldon, Gray’s Hills, the Grampians, and Whalesback. In 1878 Haldon engaged the first regular rabbiters to be employed in the Mackenzie Country. Within the next few years 60 rabbiters were working on Benmore. Still pinning his faith in fences, Tripp organised a petition for a further rabbit fence to be erected up the Rangitata valley. The Government’s experience with the Mackenzie Country fence decided it to shelve his scheme.

Failure of the fence resulted in a flood of suggestions coming forward, one coming from an expert in England, Mr Robinson, who said that if rabbits were inoculated with a certain virus, they would suffer from liver rot. Professor Thomas, of Auckland, sent by the Government to investigate certain diseased Wairarapa rabbits, found them to be suffering from a bladder worm. To calm human fears about catching this disease, he pointed out in his report: “The natives of Abyssinia are, almost without exception, infested with the human unarmed tapeworm, and they regard their parasite as necessary for the maintenance of‘health, asserting that, in many ways, it has a beneficial influence.” Professorial assurance about Abyssinian worms did not, however, sway New Zealand public opinion in favour of encouraging any form of disease in rabbits, and their infection by virus was prohibited. It was thought that rabbits could be checked by their natural enemies, so stoats, weasels and ferrets were imported in quantity from 1882 onwards, and were for a time, strictly protected. It seems that stoats and weasels attacked native birds as earnestly as they attacked rabbits. The methods of destruction now used are trapping and poisoning with strychninised oats or carrots or with phosphorised pollard, according to the time of the year. In special cases, fumigation with poisonous gas has been successful. The effect of poisoning on ground bird-life has been disastrous. By canning out these methods of control fcore extensively, rabbit boards expect to reduce rabbits in the Mackenzie Country. The Mackenzie Rabbit Board, constituted in 1949, takes in 360,000 acres of the south-east-ern part of the Mackenzie Basin, which includes Sawdon, the Grampians, Gray’s Hills, Haldon and Black

Forest stations. Up to March, 1950, their recorded catches were 367,000 rabbits counted, and another 500,000 estimated to be destroyed by phosphorised poisoning. By March, 1951, a further 155,000 rabbits were caught, and an estimated additional 440,000 destroyed. But dealing with rabbits alone does not stop denudation of the land. To cope with the problem, a Committee of Inquiry appointed by the Government recommended, in 1938, that “statutory and administrative measures should be taken at the earnest opportunity to inaugurate a programme to handle the serious soil erosion, soil conservation, and land utilisation problems that now face us.” In 1941 the Soil Conservation and Rivers Control Act waa passed; later a council was set up, and, in 1944, Catchment Boards were constituted, to work out methods of, combating soil erosion./The Waitaki River Catchment area, which includes the Mackenzie Country, is constituted a Soil Conservation District and administered by a local committee under the Soil Conservation and Rivers Control Council. T£e question of denudation has been a much-discussed topic in recent years, and various schemes have been offered to combat it. Some experts consider that the high country should be firstly a soil and water conservation area, with pastoral occupation a secondary consideration; that runholders should guard against overstocking and too much burning; that rents from highcountry lands should be used for conservation purposes; that eroded areas should be fenced off from stock, the owner being compensated by a proportionate reduction in rental. Another, but less obvious, cause of erosion is the small, uneconomic grazing run that has to be worked to maximum capacity to make it pay. It is suggested that such runs should bo regrouped. Erosion has been the subject of comment by overseas observers. A visitor from the American Museum of Natural History, Dr. R. Cushman Murphy, wrote in the "New Zealand Geographer” (1952): “New Zealand, a land of still immature and thin-skinned soils,' is bleeding dangerously. It is doubtful whether the drastic changes brought about in hilly areas by. heedless clearing, burning, and overgrazing could have been paralleled by all the men and machinery employed in digging the Panama Canal.” Dr. Murphy pointed out that danger lay in the fact that the forces of erosion have had time to gain frightening momentum. He wrote: “The lag between what the few know and what all should know is great.”

Meanwhile, erosion goes on. [The above article is the last of * series selected for publication in “The Press’’ from a history of the Mackenzie Country written by William Vance, Field Research Officer, Alexander Turnbull Library.]