VALUE OF BIIWS TO MAN. 59 



the economic ornithologist, lead him to accept as facts the 

 extreme statements made by competent investigators. 



It will be seen from the foregoing explanations that, while 

 a large nmiiber of injurious insects found in a bird's stom- 

 ach may indicate its usefulness, it may not always mean that 

 it has eaten a great bulk or quantity of such food. 



The question which most interests the farmer, however, 

 is, not so much what birds require to sustain life, as how 

 much they will eat if they can get their fill. If in times of 

 plenty birds will eat more than they really need, then they 

 become more useful or injurious, as the case may be, than 

 they would l)e if they ate only enough to live. The amount 

 of food that has been found in l)irds' gizzards indicates that 

 they will eat until surfeited. 



Professor Beal, who has examined the contents of over 

 twenty thousand stomachs, says, regarding this habit : — 



The majority of people have no idea of how much these insects can 

 be compressed in the stomach of a bird. It is often the case tliat when 

 a stomach lias been opened, and the contents j^laced m a pile, the lieap 

 is two or three times as large as the original stomach with the food all 

 in it. Moreover, in the cases Avhere remarkable numbers of insects 

 have been found, the crops or gullets usually have been full, as well as 

 the stomach itself. It is a fact, perhajjs not generally known, that Avith 

 birds that have no special enlargement of the gullet in the nature of a 

 crop, the whole gullet is \ised for the purpose ; and when favorite food 

 is abundant, the l)ird will till itself to the throat. I have seen a Snow- 

 bird so full of seeds that they were plainly in sight when the beak was 

 opened, and from the l)ill to the stomach was a solid mass of seed. 

 The stomachs of birds are often packed so hard and tight with food 

 that it is a wonder how the jjrocess of digestion can go on ; but it does, 

 nevertheless. 



In giving the maximum amounts of food found in birds' 

 stomachs, I shall be ol)liged to refer to the publications of 

 the Bureau of Biologfical Survey of the United States De- 

 partment of Agriculture ; and it is but just to say here 

 that the world owes much to Dr. ^Slerriam, chief of the 

 Bureau, for his indefatigaljle labors in behalf of science and 

 agriculture. 



In connection with the work of the survey, the contents 

 of more than thirty-tive thousand bird stomachs have been 



