CHAPTER I. 



THE METHODS OF STUDYING THE FOOD OF BIRDS. 



The accurate determination of the feeding habits of birds 

 must form the foundation of any adequate knowledge of their 

 economic status. To determine these habits two principal 

 methods are available : (1) the birds may be watched in their 

 natural haunts and the food they take be observed as care- 

 fully as possible ; (2) the birds may be killed and the food 

 found in their alimentary canals examined to determine its 

 nature. A third method, that of observing the food prefer- 

 ences of birds in captivity, is chiefly valuable in helping to 

 determine the amount of food eaten by birds, although con- 

 siderable information may thus be obtained also regarding 

 their choice of food. 



The first of these methods may be readily employed in 

 determining the varieties of vegetable food that adult birds 

 eat, and in exceptional cases is of value in determining the 

 animal food of such birds. It is of greatest value, however, 

 when applied to the nestlings, especially in the modification 

 of the method first successfully employed by Professor F. H. 

 Herrick, and described in detail later in this chapter. 



To the majority who would learn at first hand what birds 

 eat, field-work is the only sort that appeals. Only those with 

 the genuine scientific spirit are willing to soil their fingers 

 with dissection or to spend hours in identifying the contents 

 of a single stomach, even though possessed of sufficient expe- 

 rience to carry on such an investigation. Even in field-work 

 an extensive knowledge of animals and plants is necessary if 

 one would name half the objects he sees in birds' bills. But 

 while it is highly desirable to ascertain exactly what birds eat, 

 it by no means follows that a person should wait until he has 



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