MYRIAD DESCENDANTS

Dominion, Volume 26, Issue 184, 2 May 1933, Page 7

MYRIAD DESCENDANTS

Breeding Rate of Rabbits Revealed in Bulletin THE NEED FOR CONTROL Most, people have a general knowledge of the danger of the rabbit pest, but few realise the extent to which rabbits are capable of - increasing in a given time, particularly under congenial climatic conditions like those existing in New Zealand. With a view to calling attention to the menace the Department of Agriculture has had prepared an authoritative bulletin dealing with the pest and its control. The bulletin states that one pair of rabbits is capable of multiplying into 9,(134,416 rabbits at the end of the third year. The authors of the publication are Mr. D. Munro and Mr. R. Wright, two of the principal ’inspectors of the Live Stock Division of the Department. Copies of the bulletin have been circulated to local bodies in rural areas, dairy company directorates, rabbit boards, and other interested parties. Stock-carrying Capacity. Messrs. Munro and Wright work out in mathematical detail the various stages by which one pair of rabbits would increase in three years Io between 9,000,000 and 10,000,000.' "This,” they add, “is a fact which it would be well for every settler to iix very clearly in bis mind. The figures stated present an interesting problem. It is estimated that six or seven rabbits will eat or destroy as much grass as would graze one sheep: but. allowing that ten rabbits equal one sheep, it is evident that one pair of rabbits is capable of reducing in three years the stock-carrying capacity of our lands to the extent of 1,000,000 sheep. “Rabbits are keen judges of pasture, their movements are not restricted by ordinary stock-fences, and, having a more or less free choice, they select the sweetest and most nutritious grasses.” the bulletin continues. "Therefore the stock-feeding value of the pastures largely depends on the freeness of the lands from rabbit infestation. The economic loss to this Dominion through the depredations of the rabbit pest is extremely large, running into millions of pounds each year. Over a ten-year period. 1920 to 1929 inclusive, the number of rabbit-skins exported was 149.450.537. Those exported represent con-, siderably less than half the rabbits actually destroyed, to which must be added Hie number still remaining. Assuming that six or seven rabbits do equal one sheep, and estimating the value of a sheep at 10/- per year during the period mentioned, one can more readily appreciate the annual loss from faulty or inadequate control of the pest Methods of Destruction. "Ordinary farming operations are carried out in season according to a preconceived plan as dictated by seasonal conditions: lambing will commence and the dairy herd come to protit at a time when the best results may be expected with a minimum of risk, and in dealing with the rabbit pest the same principle should be adopted, the expenditure and effort being applied at the seasons which will give the best results. "The seasons al which I lie attack on '

the pest should be made and sequence in which the various methods of destruction should be applied will have an important bearing on the success or failure of the year’s work. The general breeding season will commence about the beginning of August and continue till the end of March. Saturation point in the season’s Increase (although not matured) will be reached in March, and there then remains approximately four months in which to reduce the pest to a minimum without fear of reinforcements. Therefore the early autumn and winter poisoning should be regarded as the starting-point in the year’s operations. “The next point to consider is how can the greatest number of rabbits be destroyed in the shortest time possible at a minimum of cost. A variety of methods are available—namely, poisoning by Phospborised pollard, jam poisons, and strychnined pollard, carrots, oats, swedes, or apples; gassing with carbon bisulphide or cyanogas; traps, dogs, gun, and ferrets. Each and all of the methods enumerated may be usefully employed if applied at the correct season and in the proper sequence. A brief study of each will serve to determine their relative value and the sequence in which they should be used.” Full details are given of the various methods of destruction.