Checking the Waste: A Study in Conservation

by Mary Huston Gregory

A careful examination of the harm done by birds leads to the belief that the damage is usually caused by a very large number of one species of birds living in a small area. In such cases so great is the demand for food of a particular kind that the supply is soon exhausted, and the birds turn to the products of the field or orchard. The best conditions exist when there are many varieties of birds in a region, but no one variety in great numbers, for then they eat many kinds of insects and weeds, and do not exhaust all the food supply of one kind. Under such circumstances, too, the insect-eating birds would find plenty of insects without preying on useful products, and the insects would be held in check, so that the damage to crops would be slight.

The following are examples of the food eaten by birds and the good that they thus accomplish to man:

During the outbreak of Rocky Mountain locusts in Nebraska, a scientific observer watched a long-billed marsh wren carry thirty locusts to her young in an hour and the same number was kept up regularly. At this rate, for seven hours a day, a nest-ful of young wrens would eat two hundred and ten locusts a day. From this he calculated that the birds of eastern Nebraska would destroy daily nearly 163,000 locusts.

A locust eats its own weight in grain a day. The locusts eaten by the baby birds would therefore be able to destroy one hundred and seventy-five tons of crops, worth at least ten dollars a ton, or one thousand seven hundred and fifty dollars.

So we see that birds have an actual cash value on the farm. The value of the hay crop saved by meadow-larks in destroying grasshoppers has been estimated at three hundred and fifty-six dollars on every township thirty-six miles square.

An article contributed to the New York Tribune by an official in the Department of Agriculture estimated the amount of weed seeds annually destroyed by the tree sparrow in the state of Iowa on the basis of one-fourth of an ounce of seed eaten daily by each bird. Supposing there were ten birds to each mile, in the two hundred days that they remain in the region, we should have a total of 1,750,000 pounds, or eight hundred and seventy-five tons, of weed seed consumed in a single season by this one species in the one state. In a thicket near Washington, D. C. was a large patch of weeds where sparrows fed during the winter. The ground was literally black with the seeds in the spring but on examining them it was found that nearly all had been cracked and the kernels eaten. A search was made for seeds of various weeds but not more than half a dozen could be found, while many thousands of empty seed-pods showed how the birds had lived during the winter.

In no place are birds more important than in the forests, where they save hundreds of thousands of dollars worth of valuable timber each year. In forests there can be no rotation of crops and no cultivation, and spraying, which keeps down the insect pests in the orchard, is impossible here because of the expense. It would not pay to spray two or three times a year a crop of timber that requires a lifetime to grow. So in the forests the owner must depend entirely on birds for his protection. How great the destruction of our forests would be is shown by the fact that the damage at present is estimated at $100,000,000, in spite of the fact that a vast army of birds is working tirelessly, summer and winter, to devour the insects! The debt of the forester to the birds can hardly be estimated.

A full variety of birds will thoroughly protect a farm and orchard. The sparrows will destroy the weed seeds; the hawks and kites, flying by day, will catch the meadow mice and other small mammals, and the owls will pounce on those that venture forth at night. Of the insect-eating birds, the larks, wrens, thrushes and sparrows search the ground for worms, eggs and insects under leaves and logs everywhere. The nuthatches, vireos, warblers and creepers search every part of the tree, while the woodpeckers tap beneath the bark for grubs and worms. The fly-catching birds catch their insect food on the wing among the trees and branches, and, last of all, the swallows skim high in the air and catch the few insects that rise high above the tree-tops.

Thus each family has its part of the work and the good they do is almost too great to calculate. Without this check it would be impossible for any green thing to flourish. So vast an amount of food is required to feed the great army of insects that the task would be impossible in any other way.

A brief description of some of the common birds and their food habits is given here that farmers may know their friends, and that people everywhere may learn to protect the useful birds and drive out the few that do the mischief.