WILD LIFE ENEMIES

Forest and Bird, Issue 44, 1 May 1937, Page 4

WILD LIFE ENEMIES

By E. V. Sanderson.

NATURAL AND UNNATURAL

THE casual observer, the world over, is invariably impressed with the idea that if the natural enemy of any species could be eliminated then that species would increase and multiply. Such has been the fallacious idea with hunters especially, in the past. And what is the almost universal result of the setting into action of this idea and the killing of vast numbers of so-called vermin—less game? The biologist will, however, tell a totally different story. He will point out that all Nature is war from the infinitesimal diatom living in the sea right up to or down to Man —the greatest destroyer of alland that every species has and must have a natural enemy for the sake of its own preservation. Man certainly has no other natural enemy besides himself, but he needs none because he is quite capable of preventing his numbers overcoming his food supply. Note for instance that when man invents or fashions somethingsay an aeroplane, poisonous gas, or more powerful explosive, things which might be put to uses beneficial to his requirementshis first thought is “By jove this will be a grand thing to kill the other fellow with!” He is ready to function at any moment as Nature decreed and act as his own natural enemy. The game bird hunter who advocates the killing of hawks is at very serious disadvantages in securing accurate data for his conclusions. First of all, most wild creatures immediately detect movement and the upland bird hunter must move. He heralds his approach with his heavy tramping, by whistling or calling to his dog and intermittently discharging his gun. As a result most wild creatures flee before him or seek cover. All wild life assumes an abnormal state of excitement. The wild cat is safe lying on the high branch of some tree and that scent at the foot of the tree is not what the hunter takes it to be—an opossum. The stoat and weasel have disappeared, the rats were already safe from view before the hunter approached. But what about the hawk? It, the wise old bird, connects the sound of a gun with easily got

food in the shape of wounded game, as the result of long speculative or bad shots, and is therefore attracted to the vicinity of the gunner, who reports with all sincerity at the next Acclimatisation meeting that hawks are numerous and are the real enemies of game birds. How different is it with the trained observer! He is prepared to keep still and remain concealed for hours at a time. All wild life then assumes its accustomed habits and peculiarities. He sees the rabbit quietly feeding with a hop or a skip, anon, the pheasant as it leisurely picks up morsels from the ground, the quail stringing their way along some usual beat oblivious of the crouching cat. But what is now happening? Why that sudden arresting of feeding and then an equally sudden stampede, even extending to domestic animals? Homo sapiens approaches with his gun and his hereditary ally the dog. The special place of the natural enemy in what Man is pleased to call the lower creatures is really in many cases to act in a merciful manner by killing off the diseased, the starving, the wounded or otherwise weakened and already doomed individuals of the species preyed upon. In this manner it assists in no small degree to maintain the virility of the living by removing the diseased individuals promptly and reducing the numbers to the carrying capacity of the feeding ground. The living having now a sufficiency of food and being free from disease will multiply in the spring. The lion, the tiger, the hawk, the eagle, the shag, etc., do not secure their prey easily. Well-fed desirable prey is wary, alert, virile, fleet of foot or wing and not easily captured, therefore, the flesh-eating creature has usually to be content to take the easiest caughtthe weak individual. No! conservation can never succeed by destroying natural enemies, but rather must it fail as a consequence of any such indiscriminate destruction. Definite evidence of this is obtainable in almost every country where it is practised. The secret of success in conservation lies in the preservation or the setting up of the

natural habitat. Food and cover, especially winter food, will decide the carrying capacity of the habitat, which may be likened to a pastoral run in that it will carry what it can winter, except that some wild creatures will migrate to other feeding grounds if available. New Zealand as a whole, will, however, carry only that wild life which it can winter, and thus it has always been. This carrying capacity can only be varied by adding to or destroying the natural food supply or augmenting it artificially. When, however, the term “Vermin” is applied to unnatural or exotic enemies to wild life, the argument is quite different, and we need not go beyond New Zealand for many notable examples of inevitable results, as witness the deer, goats, etc., as unnatural enemies of our plant life. Stoats, weasels, rats, cats, etc., are also unnatural to our native bird life, which had prospered for ages upon ages in association with its natural enemies. They were then suddenly attacked by these strange enemies which had new and different methods of securing their prey. Add to this the effect of imported disease, with the destruction of the natural habitat; then it can be seen that the calamities were indeed overwhelming. Take for instance the introduction of the Little or German owl. The

fantail had long been accustomed to prey upon flying insects right up to dusk, and the attack was then taken up by bats until total darkness. Then the rats came out to prey upon eggs, nestlings, etc., and to be preyed upon themselves by the morepork. The Little owl, however, takes the fantail in daylight, a form of attack which the fantail or its ancestors had never previously experienced. The purposely introduced Little Owl thus played sad havoc with one of man’s most useful allies. But then we must not forget that Man is his own natural enemy.