[30] The following quotation from I. P. Trimble, A Treatise on the Insect Enemies of Fruit and Shade Trees, bears out this statement: "On the fifth of May, 1864, ... seven different birds ... had been feeding freely upon small beetles.... There was a great flight of beetles that day; the atmosphere was teeming with them. A few days after, the air was filled with Ephemera flies, and the same species of birds were then feeding upon them."
During the outbreak of Rocky Mountain locusts in Nebraska in 1874-1877, Professor Samuel Aughey saw a long-billed marsh wren carry thirty locusts to her young in an hour. At this rate, for seven hours a day, a brood would consume 210 locusts per day, and the passerine birds of the eastern half of Nebraska, allowing only twenty broods to the square mile, would destroy daily 162,771,000 of the pests. The average locust weighs about fifteen grains, and is capable each day of consuming its own weight of standing forage crops, which at $10 per ton would be worth $1743.26. This case may serve as an illustration of the vast good that is done every year by the destruction of insect pests fed to nestling birds. And it should be remembered that the nesting season is also that when the destruction of injurious insects is most needed; that is, at the period of greatest agricultural activity and before the parasitic insects can be depended on to reduce the pests. The encouragement of birds to nest on the farm and the discouragement of nest robbing are therefore more than mere matters of sentiment; they return an actual cash equivalent, and have a definite bearing on the success or failure of the crops.—Year Book of the Department of Agriculture.
[31] Directions for the treatment of these pests may be found in pamphlets issued by the U. S. Department of Agriculture.
Reference Books
elementary
Hunter, Laboratory Problems in Civic Biology. American Book Company.
Beebe, The Bird. Henry Holt and Company.
Bigelow, Applied Biology. Macmillan and Company.
Davison, Practical Zoölogy. American Book Company.
Herrick, Household Insects and Methods of Control. Cornell Reading Courses.