Number of Insects Destroyed by Birds in the Eastern United States

Birds feed their young, on an average, about two hundred insects a day. If we take fifteen days as the average time that young birds remain in the nest, the young during this time would devour about three thousand insects. A recent bird-census of the United States, made by the Bureau of Biological Survey, showed that there was an average of one pair of birds per acre on the farms of the eastern United States. East of the Mississippi River there are about 375,000,000 acres of farmland supporting an equal number of pairs of birds. These birds in rearing one brood of young would destroy about 1,100,000,000,000 insects.

This is the amount for only two weeks eaten by the young birds alone while in the nest. To get some conception of the total amount of food eaten by all birds, to this must be added the. insects eaten by the second and third broods which some species raise, those eaten by the adult birds and those eaten by the young birds after leaving the nest.

The amount eaten by the young after leaving the nest and by the adults in a month would doubtless equal the amount required to feed the young for a half-month in the nest. This would make a monthly total of about 2,000,000,000,000 insects destroyed by birds on the farms of the east­ern United States, or for the summer season about 10,000,000,000,000 insects.

If these insects averaged an inch in length and were placed end to end, they would make a proces­sion 160,000,000 miles long, which, if it were to travel at the rate of a mile a minute, would require three hundred years to pass any given point. This would reach to the sun and almost back again; it would reach the moon and return three hundred times; it would encircle the earth sixty-four hundred times.

If the insects were placed side by side one inch apart they would make a band fifty feet wide extending to the moon, and would form a belt five hundred feet wide extending all the way around the earth. These insects, if placed an inch apart each way would form a sheet that would completely cover the State of Delaware.

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