Chapter 6

THE ECONOMIC VALUE OF BIRDS

Wild birds are now generally protected by law. Wander where you will through every province of Canada, and almost every nook and corner of the United States, you will find that the lawmaker has been there before you, and has thrown over the birds the sheltering arm of prohibitory statutes. Legislators are not usually supposed to spend much energy on drafting and enacting measures unless it is thought that these will result in practical benefit to at least some portion of their constituents. Legislative bodies are not much given to appropriating hundreds of thousands of dollars annually for the enforcement of a law which is purely sentimental in its nature. It is clear, therefore, that our law makers regard the wild bird life as {102} a great value to the country from the standpoint of dollars and cents.

_Destructiveness of Insects._--If we go back a few years and examine certain widely read publications issued by the United States Department of Agriculture, we can understand more fully why our legislative bodies have regarded so seriously the subject of bird protection. In one of the Year Books of the Department we read that the annual loss to the cotton crop of the United States by insects amounts to sixty million dollars. We learn, too, that grasshoppers and other insects annually destroy fifty-three million dollars' worth of hay and that two million dollars' worth of cereals are each year eaten by our insect population. In fact, we are told that one-tenth of all the cereals, hay, cotton, tobacco, forests, and general farm products is the yearly tax which insects levy and collect. In some parts of the country market-gardening and fruit-growing are the chief industries of the people. Now, when a vegetable raiser or fruit grower starts to count up the cost of {103} his crops, one of the items which he must take into consideration is the 25 per cent. of his products which goes to feed the insects of the surrounding country.

Not all insects are detrimental to man's interests, but as we have just seen the Government officially states that many of them are tremendously destructive. Any one who has attempted to raise apples, for example, has made the unpleasant acquaintance of the codling moth and the curculio. Every season the apple raisers of the United States expend eight and one-quarter million dollars in spraying, to discourage the activities of these pests. In considering the troubles of the apple growers we may go even farther and count the twelve million dollars' worth of fruit spoiled by the insects despite all the spraying which has taken place. Chinch bugs destroy wheat to the value of twenty million dollars a year, and the cotton-boll weevil costs the Southern planters an equal amount.

_Plagues of Insects._--Every now and then we read {104} of great plagues of insects which literally lay waste a whole section of country. History tells of these calamities which have troubled the civilized world from the days of Pharaoh to the present time. During the summer of 1912 there was a great outbreak of army worms in South Carolina. In innumerable millions they marched across the country, destroying vegetation like a consuming fire. In the year 1900 Hessian flies appeared in great numbers in Ohio and Indiana, and before they subsided they had destroyed absolutely two and one-half million acres of the finest wheat to be found in the Middle West, and wheat land dropped 40 per cent. in value.

Closing this Year Book, with its long tables of discouraging statements, we may find more cheerful reading if we turn to another Agricultural Department publication entitled, "Some Common Birds and Their Relation to Agriculture; Farmers Bulletin number Fifty-four." We need peruse only a few pages to become impressed with the fact that our Government Biological Survey has made an {105} exhaustive and exceedingly thorough investigation of the feeding habits of the wild birds that frequent the fields and forests. The reports of the economic ornithologists herein given are almost as surprising as the sad records given by the entomologists in the Year Book. We learn that birds, as a class, constitute a great natural check on the undue increase of harmful insects, and furthermore that the capacity for food of the average bird is decidedly greater in proportion than that of any other vertebrate.

_Some Useful Birds._--Most people who have made the acquaintance of our common birds know the friendly little Chickadee, which winter and summer is a constant resident in groves of deciduous trees. It feeds, among other things, on borers living in the bark of trees, on plant lice which suck the sap, on caterpillars which consume the leaves, and on codling worms which destroy fruit. One naturalist found that four Chickadees had eaten one hundred and five female cankerworm moths. With scalpel, tweezers, and microscope these moths were examined, {106} and each was found to contain on an average one hundred and eighty-five eggs. This gives a total of nearly twenty thousand cankerworm moth eggs destroyed by four birds in a few minutes. The Chickadee is very fond of the eggs of this moth and hunts them assiduously during the four weeks of the summer when the moths are laying them.

The Nighthawk, which feeds mainly in the evening, and which is equally at home in the pine barrens of Florida, the prairies of Dakota, or the upper air of New York City, is a slaughterer of insects of many kinds. A Government agent collected one, in the stomach of which were the remains of thirty-four May beetles, the larvae of which are the white grubs well known to farmers on account of their destruction of potatoes and other vegetables. Several stomachs have been found to contain fifty or more different kinds of insects, and the number of individuals in some cases run into the thousands. Nighthawks also eat grasshoppers, potato-beetles, cucumber-beetles, boll-weevils, leaf-hoppers, and numerous gnats and {107} mosquitoes. Surely this splendid representative of the Goatsucker family deserves the gratitude of all American citizens.

Among the branches of certain of our fruit trees we sometimes see large webs which have been made by the tent caterpillars. An invading host seems to have pitched its tents among the boughs on all sides. If undisturbed these caterpillars strip the foliage from the trees. Fortunately there is a bird which is very fond of these hairy intruders. This is the Cuckoo, and he eats so many that his stomach actually becomes lined with a thick coating of hairs from their woolly bodies. The Baltimore Oriole also is fond of rifling these webs.

Another well-known bird that helps to make this part of the world habitable is the Flicker. It is popular in every neighbourhood where it is found and is known by a wide variety of local names, over one hundred and twenty-five of which have been recorded. Golden-winged Woodpecker some people call it. Other names are High-holder, Wake-up, {108} Walk-up, Yellowhammer, and Pigeon Woodpecker. The people of Cape Hatteras know it as Wilkrissen, and in some parts of Florida it is the Yucker-bird. Naturalists call it _Colaptes auratus_, but name it as you may, this bird of many aliases is well worthy of the esteem in which it is held. It gathers its food almost entirely from the ground, being different in this respect from other Woodpeckers. One may flush it in the grove, the forest, the peanut field, or the untilled prairie, and everywhere it is found engaged in the most highly satisfactory occupation of destroying insect life. More than half of its food consists of ants. In this country, taken as a whole, Flickers are very numerous, and the millions of individual birds which have yet escaped the guns of degenerate pot hunters constitute a mighty army of destruction to the _Formicidae_.

Let us not forget that any creature which eats ants is a decided boon to humanity. Ants, besides being wood borers, invaders of pantries, killers of young birds, nuisances to campers and barefoot {109} boys, care for and perpetuate plant lice which infest vegetation in all parts of the country to our very serious loss. Professor Forbes, in his study of the corn plant louse, found that in spring ants mine along the principal roots of the corn. Then they collect the plant lice, or aphids, and convey them into these burrows and there watch and protect them. Without the assistance of ants, it appears that the plant lice would be unable to reach the roots of the corn. In return for these attentions the ants feast upon the honey-like substances secreted by these aphids. The ants, which have the reputation of being no sluggards, take good care of their diminutive milch cattle, and will tenderly pick them up and transport them to new pastures when the old ones fail. Late in the summer they carefully collect all the aphid eggs that are obtainable, and taking them into their nests keep them safe during the winter. When spring comes and the eggs hatch, the ants gather the young plant lice and place them on plants. It may be seen, therefore, that the Flicker {110} by digging up ants' nests and feeding on the inhabitants has its value in an agricultural community.

_The Question of the Weed Seeds._--The work of the Chickadee, the Nighthawk, the Cuckoo, and the Flicker is only an example of the good being done by at least two-thirds of birds in the United States, and most of the remainder are not without their beneficial qualities. When the coming of winter brings a cessation of insect life, many birds turn to the weed patches for food. Especially is this the case with the various varieties of native Sparrows.

No one has yet determined just how many weed seeds one of these birds will eat in a day. The number, however, must be very great. An ornithologist, upon examining the stomach of a Tree Sparrow, found it to contain seven hundred undigested pigeon-weed seeds, and in the same way it was discovered that a Snow Bunting had taken one thousand seeds of the pigweed at one meal.

Mr. E. H. Forbush, the well-known Massachusetts naturalist, frequently amuses himself by {111} observing the birds near his house as they feed on the millet seed that he provides for them. Speaking of some of the things he saw here, he says, "A Fox Sparrow ate one hundred and three seeds in two minutes and forty-seven seconds; another, one {112} hundred and ten in three minutes, forty-five seconds; while still another Song Sparrow ate one hundred and fifty-four in the same length of time. This Sparrow had been eating for half an hour before the count began and continued for some time after it was finished." It is readily seen that thirty seeds a minute was below the average of these birds; and if each bird ate at that rate for but a single hour each day it would destroy eighteen hundred seeds a day, or twelve thousand six hundred a week. Some day the economic ornithologists under the leadership of Professor F. E. L. Beal, America's leading authority on the subject, may give us a full and exhaustive account of what the various birds do for us in the way of keeping down the great scourge of grass and weeds with which the farmers have to deal. In the meantime, however, we may bear in mind that enough evidence already has been accumulated to prove that as destroyers of noxious weed seeds the wild birds are of vast importance.

_Dealing with the Rodent Pests._--In addition to {113} weeds and insects, there is yet another group of pests, some representatives of which may be found in every neighbourhood. It is composed of rabbits, ground squirrels, prairie dogs, mice, and the like. They all possess long front teeth for gnawing, and constitute the Order of Rodents. Some species destroy fruit trees by gnawing away the bark near the ground, others attack the grain stacked in the field or stored in the granary. As these little sharp-eyed creatures are chiefly nocturnal in their habits, we seldom see them; we see only the ruin they have wrought. In some of the American ports incoming vessels are systematically fumigated to kill the rats for fear they may bring with them the bubonic plague. In April, 1898, while engaged in field natural history work in Hyde County, North Carolina, I found the farms along the north shore of Matamuskeet Lake were overrun by swarms of large brown rats that burrowed in the ground everywhere, and coming out at night wrought havoc and destruction on the farm lands. The whole country was up {114} in arms and the farmers were appealing for State and Federal aid to help them rid the land of this terrible scourge. In short, the rodents, as a class, are regarded as decidedly detrimental to the interests of mankind.

_The Terror That Flies by Night._--Among the chief enemies of rodents in North America are the nineteen species of Owls, untold numbers of which are abroad every night searching through fields and forests for just such creatures as these. The digestive processes of Owls are such that the hard, indigestible portions of their food are disgorged in the form of balls and may often be found beneath their roosting places. One of our most odd-looking birds is the Barn Owl. Being nocturnal in its habits it is rarely seen unless one takes the trouble to climb into unfrequented church towers, the attics of abandoned buildings, or similar places which they seek out for roosting purposes. Some years ago the naturalist, Dr. A. K. Fisher, discovered that a pair of Barn Owls had taken up their abode in one of the towers {115} of the Smithsonion Institution building. He found the floor thickly strewn with pellets composed of bones and fur which these birds and their young had disgorged. He collected two hundred of these {116} and took them to his laboratory. A painstaking examination showed that they contained four hundred and fifty-three skulls. Here is his list made out at the time: two hundred and twenty-five meadow mice, two pine mice, twenty shrews, one star-nosed mole, and one Vesper Sparrow. It is plain to be seen that great good was accomplished in the community by this pair of Owls and their young, for the evil effects of the rodents in life must have far overbalanced the good service of the one useful Vesper Sparrow.

_A Seldom Recognised Blessing._--There are some large predatory birds which destroy the lives of many game birds and others of the weaker species. On game farms, therefore, an unpleasant but necessary task is the shooting or trapping of Hawks and Owls. At first thought it might seem best to wage a war of absolute extermination on these offenders, and some game-keepers urge that this should be done. Personally I am opposed to any such course of action, one reason being that this would not {117} necessarily forward the best interests of the game birds it is desired to serve. So important and yet so unexpected is the ultimate effect of the activities of predatory creatures that in a state of nature I am convinced the supply of game birds is increased rather than decreased by being preyed upon. Like all other creatures, birds are subject to sickness and disease, but by the laws of nature it appears that they are not designed to suffer long. Their quick removal is advisable if they are to be prevented from spreading contagion among their fellows, or breeding and passing on their weakness to their offspring. Sometimes the Hawk, dashing at a covey of game birds, may capture one of its strongest and healthiest members, but the chances are that the afflicted member, which is not so quick on the rise or is a little slower on the wing, is the one to be taken. Just as some savages are said to put to death the incompetent and unfit, so do the laws operate which govern wild life. If, therefore, we should destroy all the Hawks, Owls, wild cats, foxes, skunks, {118} snakes, and other predatory creatures, it is an open question whether in the long run our game birds would be the gainers thereby.

Some time ago I visited a large game farm in one of the Southern States, where for several years the owner had been engaged in raising English Ring-necked Pheasants. The gamekeeper stated that there were about six thousand of these brilliantly coloured birds on the preserve at that time. He also pointed with pride to an exhibit on the walls of a small house. An examination showed that the two sides and one end of this building were thickly decorated with the feet of Hawks, Crows, Owls, domestic cats, minks, weasels, and other creatures that were supposed to be the enemies of Pheasants. Two men were employed on the place to shoot and trap at all seasons, and the evidences of their industry were nailed up, to let all men see that the owner of the big game farm meant to allow no wild bird or animal to fatten on his game birds.

A year later I again visited the same preserve and {119} found great lamentation. More than five thousand Pheasants had been swept away by disease within a few weeks. Is it going too far to say that the gunmen and trappers had overdone their work? So few Hawks or Owls or foxes had been left to capture the birds first afflicted, that these had been permitted to associate with their kind and to pass on weakness and disease to their offspring until the general health tone of the whole Pheasant community had become lowered. In the end five-sixths of the birds had succumbed to the devastations of disease.

All birds have their part to play in the great economy of the earth, and it is a dangerous experiment to upset the balance of Nature.

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