in devouring small rodents, in destroying the seeds of harmful plants, and in acting as scavengers.
Leading entomologists estimate that insects cause an annual loss of at least two hundred million dollars to the agricultural interests of the United States. The statement seems incredible, but is based upon reliable statistics. This, of course, does not include the damage done to ornamental shrubbery, shade and forest trees. But if insects are the natural enemies of vegetation, birds are the natural enemies of insects. Consider for a moment what the birds are doing for us any summer day, when insects are so abundant that the hum of their united voices becomes an almost inherent part of the atmosphere.
In the air Swallows and Swifts are coursing rapidly to and fro, ever in pursuit of the insects which constitute their sole food. When they retire, the Nighthawks and Whip-poor-wills will take up the chase, catching moths and other nocturnal insects which would escape day-flying birds. The Flycatchers lie in wait, darting from ambush at passing prey, and with a suggestive click of the bill returning to their post. The Warblers, light, active creatures, flutter about the terminal foliage, and with almost the skill of a Hummingbird pick insects from leaf or blossom. The Vireos patiently explore the under sides of leaves and odd nooks and corners to see that no skulker escapes. The Woodpeckers, Nuthatches, and Creepers attend to the tree trunks and limbs, examining carefully each inch of bark for insects' eggs and larvae, or excavating for the ants and borers they hear at work within. On the ground the hunt is continued by the Thrushes, Sparrows, and other birds, who feed upon the innumerable forms of terrestrial insects. Few places in which insects exist are neglected ; even some species which pass their earlier stages or entire lives in the water are preyed upon by aquatic birds.
