VALUL OF BIRDS 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 number 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 be if they ate only enough to live. The amount 
of food that has been found in birds’ 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 that when 
a stomach has been opened, and the contents placed in a pile, the heap 
is two or three times as large as the original stomach with the food all 
in it. Moreover, in the cases where 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, perhaps not generally known, that with 
birds that have no special enlargement of the gullet in the nature of a 
crop, the whole gullet is used for the purpose; and when favorite food 
is abundant, the bird will fill itself to the throat. J have seen a Snow- 
bird so full of seeds that they were plainly in sight when the beak was 
opened, and from the bill 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 process of digestion can go on; but it does, 
nevertheless. 
In giving the maximum amounts of food found in birds’ 
stomachs, I shall be obliged to refer to the publications of 
the Bureau of Biological Survey of the United States De- 
partment of Agriculture; and it is but just to say here 
that the world owes much to Dr. Merriam, chief of the 
Bureau, for his indefatigable labors in behalf of science and 
agriculture. : 
In connection with the work of the survey, the contents 
of more than thirty-five thousand bird stomachs have been 
