NO INSECTIVOROUS BIRDS MEANS NO CROPS

Forest and Bird, Issue 8, 1 March 1925, Page 2

NO INSECTIVOROUS BIRDS MEANS NO CROPS

It cannot be too widely known at the present time that any general or indiscriminate destruction of wild birds would be fraught with grave danger to the food of the people. In every country and every district where birds have been systematically destroyed, the result has been the same: (1) insect and vermin plagues; (2) serious losses in crops of all kinds; (3) failure of man to deal with the plagues; (4) efforts to bring back the birds. The greatest and most dangerous enemy of the farmer and food-producer is the insect pest. It has been stated by Mr. Walter Collinge, D.Sc., F.L.S., that it is no unusual thing to find injury done by insects to the extent of 25 to 50 per cent, of the crop; in other cases it is much beyond that. Thus the foodproducer loses tens of thousands of pounds in money; the people lose tens of thousands of pounds of food. When one considers the rate of increase in insects the value becomes very apparent of such birds as the fantail. that king of the flying insect destroyers, the grey warbler which fortunately shows every indication of prospering, and the little silver eye. that pretty little fellow which occasionally does exact a small toll from some soft fruitshe is, however, sudden death on blights, green fly (aphis), etc. Now one fly to-day would mean, should all its descendants survive. 16,000 green flies in a single week. What a good time the green flies and other moths and flies must have if we kill even a few silver eyes or fantails, and what a bad time our crops must have; but we don’t always think it is because the birds have been destroyed. Many imported birds also are insectivorous. Man himself cannot control insect pests. They increase at a phenomenal rate. They are in many cases so small as to be hardly visible to man’s eyes. They are hidden underground, and in buds, in fruit, in crannies and crevices of plants, trees, wood, rubbish I heaps, etc. Poison, traps and insecticides of various sorts have been tried, but all entail heavy outlay in money, time, and labour which can ill be afforded at this crisis.

The gipsy-moth, which in. 1859 stripped the trees of Brussels of their leaves, multiplies so quickly that a single pair might, should all their progeny live, be responsible for the destruction of all the foliage in New Zealand. The natural enemy of the insect is the insect-eating bird. “The millions of the insect world are upon us,” writes Dr. Hornaday (New York Zoological Society). The birds fight them for us.” “Birds,” says Dr. Gordon Hewitt (formerly of Manchester University, now Dominion Entomologist of Canada), “are the most powerful insecticides we have. Their rapid wings, keen eyes and ears, and sharp beaks are the weapons specially formed to deal with these plagues. The great hunter of insects, our great auxiliary,” says M. Edmond Perrier (of the Institute of France), “ is the bird.” . For want of close examination the harm done by insects is too often attributed to the very birds that are in pursuit of the insects. As Mr. Archibald, of Leeds University, says, the damage done by birds is readily detected but it is vastly exaggerated through the mistakes of careless observers, “whilst the great services they render are appreciated only by those who will examine and consider facts carefully.” The bird is extremely visible ; the grub is hidden out of sight, the fly is small and harmless-looking. The bird is six, eight, ten, or fourteen inches long the beetle is perhaps one-tenth of an inch. A great proportion of the commoner small birds of the countryside live entirely or chiefly on insects. The amount they consume is prodigious, for a bird will eat one-sixth of its own weight in a day. Beyond this comes the fact that even those species which as adults feed more or les§ on another diet, feed their young on insects — grubs, worms, and flies. And. at what time of the year is this ? In the spring and early summer, just when the destruction of injurious insects is most essential for the life and health of vegetation. Nearly all land birds are more or less valuable, and a large number are absolutely invaluable, as man’s allies in the production of his crops, whether he is a resident of the Old Country, living by the product of the soil his forefathers have tilled for centuries, or a settler bringing virgin land under cultivation. His enemy, is the insect-—mining, boring, creeping, flying— his knowledge, defying his warfare, unceasingly feeding upon his crops, destroying his green things,' devastating his fields, existing in myriads, increasing with a rapidity no other living creature can parallel.— (Royal Society for the Protection of Birds.) “I have estimated that the loss due to insect depredations (in Canada) is not less than 125 million dollars annually.” writes

Dr. Gordon Hewitt, who investigated the subject both in Great Britain and in Canada. “Birds constitute one of the chief natural factors tending to keep insects in subjection. If injurious insects were to increase without any natural control, there would be no vegetation left on this continent in a very short time. Therefore the protection of birds is essential from the point of national economy. . . . In view of the great economic value of our insectivorous birds from an agricultural . standpoint—but not forgetting the aesthetic motives, which surely need not be supported by any argument — is evident that the protection of these birds must form an important part in the maintenance or increase of our agricultural production.”( Conservation of Wild Life in Canada.) “How to keep insect pests in check is a question of the greatest importance to the whole community. ... It can be done at little or no cost by intelligently encouraging and protecting our birds.”—( Toronto Department of Agriculture.) “Without the birds the gardener and farmer would find it impossible to grow any crops at all.”— (lntelligence Department, South Australian Government.) “It may be safely said that no country in the world suffers more from insect pests than South Africa; and the cheapest and most efficient agency to check their depredations is a sufficiency of bird life.”( Professor Ernest Warren and R. Godfrey , South African Birds of Economic Value.) “Insects have hosts of enemies other than our feathered allies; but if we exterminated the native birds, the human population •of South Africa would in a few years be reduced to a condition of starvation.”(F. W. FitzSimons, Birds of South Africa.) “Man himself has wantonly destroyed his beautiful and faithful allies the birds. He is now paying the penalty in the alarming spread of germ-diseases, and in the diminution of his animal and vegetable food supply.”—(Sir H. H. Johnston, G.C.M.G.. D.Sc.) To those familiar with the truth of these pronouncements and of many like them from other distinguished authorities, it appears amazing that steps were not taken long ago to preserve and safeguard the bird life of all countries: still more amazing that so little is done to-day; that not one person in a thousand is made acquainted with the value of wild birds; and that even the most useful species are continually persecuted and destroyed in utter ignorance, of their value to the community and in total disregard of their beauty, or in order that the individual may make money by selling them alive into captivity or dead for eating, or by dealing in their skins and plumage.