xviii INTRODUCTION 



It is not generally known, however, that the 

 so-called seed-eaters both feed their young largely 

 upon insects and eat many themselves ; nor is 

 it realized how much good they do by eating 

 weed seeds. Prof. F. E. L. Beal has calculated 

 that the little Tree Sparrow in Iowa alone destroys 

 1,720,000 lbs. of noxious weed seeds every year. 

 Moreover, in summer seed-eaters eat blueberries, 

 huckleberries, strawberries, and raspberries, and 

 distribute their seeds unharmed over thousands 

 of acres wdiich would not otherwise sujiport such 

 growth. 



These facts show how imj^ortant it is that the 

 birds should be protected and encouraged, ex- 

 cept in the exceedingly few cases where for a 

 short time they eat some one cultivated crop to 

 such excess that the loss is not compensated by 

 the good they do in destro3ang pests the rest of 

 the year. The Department of Agriculture, real- 

 izing the losses that often result from the igno- 

 rant sacrifice of useful birds, constituted the 

 Division of Ornithology, now a part of the Biolo- 

 gical Survey, a court of appeal where accusations 

 against the birds could be received and investi- 

 gated. 



The method used by the division is the final 

 one — the examination of stomach contents to 

 prove the actual food of the birds. A reference 

 collection of 800 kinds of seeds and 1,000 s^Decies 

 of insects has been brought together for compari- 



