RABBITS CAUSE A HUGE LOSS TO NEW ZEALAND FARMERS

Bay of Plenty Beacon, Volume 13, Issue 86, 13 May 1949, Page 3

RABBITS CAUSE A HUGE LOSS TO NEW ZEALAND FARMERS

Among the many animals and insects that have been introduced into New Zealand few, very few, have been of any use. In most cases they have become pests. In nearly every case they were brought into the country by people who did not stop to realise the damage they were about to do. Scientists too, in some examples. But perhaps the animal that has done more harm in such a short time than any other is the rabbit.

It is one of this country’s worst pests and the Bay of Plenty has its share, in parts very much more than is wanted. There are many in the back country about Whakatane. Loss to Ne,w Zealand through rabbits every year runs into millions of pounds. It is estimated that at least £3,000.000 in sheep-carrying capacity alone is lost and this is only partly offset by the export value of skins and carcases. Present control measures that destroy about a third of the rabbit population annually are to be supplemented by further research.

The first rabbits were introduced into New Zealand about 1838 but failed to become established. Further introductions were made about the 1860’s, and by 1874 enormous numbers had begun to spread in both Islands. Legislation with the object of controlling the increase of rabbits was passed in 1876, and three years later it was made an offence to liberate them. Further Research The Animal Ecology Section of the Department of Scientific and Industrial Research, which carries out research on the habits and modes of life of animals, has given priority to„a field study of the biology of the rabbit. Much has yet to be learned on the cyclic variations in the population of the rabbit and of the best ways of extermination. An example of the latter problem occurred in Australia recently when an introduced virus infection, deadly to rabbits in captivity, proved a failure, since infected animals in the wild state wandered way to die alone. Accurate data on the rabbit in its natural state have yet to be obtained and figures given are but rough estimates. The food consumption of the rabbit is out. of all proportion to its size. It used to be estimated that the feed necessary for one sheep would be eaten by six or seven rabbits, but the Animal Ecology Section gives the estimate at ten. The breeding ewe is about 38 times the weight of the average rabbit, and yet ten rabbits will eat as much as one evs^e. The rapid breeding of the rabbit is illustrated by a wartime experience in England. On an island overrun with rabbits extermination methods destroyed all but a few pairs living in the cliffs; in less than six years, with no organised extermination, the rabbit population was back to its former size.

50 Million Rabbits? Control of the New Zealand rabbit population—estimated as oscil-. lating between 40 and 50 millions—is, of course, already taking place. Approximately 20,000,000 rabbits were destroyed in this country during 1947 (the last available figures) five-sixths of these were exported as skins and carcases, increasing the overseas trade by £1,120,219. Against this, however, must be set the annual loss on the stock-carry-ing capacity on the land, which loss alone is thought to be not lower than £3,000,000 and possibly as much as £5,000,000. The rabbit causes damage to young plantations, fouls pastures, increases weeds in pastures by selective feeding, and causes soil erosion by destruction of soil cover—all serious losses that so far cannot be estimated.

New Zealand spends £150,000 per annum from public funds on the control of the rabbit, and although, about a third of the rabbit population is destroyed each year this appears to do little more than keep a check on their numbers.