26 



BULLETIN OF 

 MASSACHUSETTS BOAED OF AGRICULTUKE. 



OENITHOLOaiCAL. 



The Regulative Influence Exerted by Birds on the Increase 

 OF Insect Pests. 



It is only by a comprehensive knowledge of the numbers, repro- 

 ductive capacity and insatiable voracity of insects, and a searching 

 inquiry into the food habits of birds during all seasons and at all 

 periods of their existence, that we are enabled to appreciate the 

 economic relations which insect-eating birds assume toward the 

 tiller of the soil. 



The number of species of insects on the globe is vast, and that 

 of "the individuals of each species is beyond comprehension. The 

 number of species is greater by far than that of all other living 

 creatures combined. More than three hundred thousand have 

 already been described. There are many thousands of unde- 

 scribed species in museums. Dr. Lintner, the distinguished en- 

 tomologist of the Empire State, considers it not improbable that 

 there are a million species of insects. Each one of these species 

 is enormously productive, and it is undoubtedly true that were the 

 progeny of one pair of insects allowed to reproduce without cheeky 

 the species would soon cover the entire habitable earth. 



The Rocky Mountain locust in its flights fills the air and hides 

 the sun. From the high peaks of the Sierra Nevada it has been 

 seen filling the valleys below and the air above as far as a power- 

 ful field glass could bring the insects within its focus. The chinch 

 bug covers the corn and grain fields in countless millions over 

 towns, counties and States. The army worm moves at times in 

 solid columns, destroying the crops in its path. The voracity of 

 insects is almost beyond belief. Says Dr. Lintner: "A certain 

 flesh-feeding larva will consume in twenty-four hours two hundred 

 times its original weight. . . . There are vegetable feeders, cater- 

 pillars, which during their progress to maturity, within thirty days, 



