METHODS OF STUDYING THE FOOD OF BIRDS. 13 



fruit-eating birds do not digest their food so thoroughly but 

 that its nature is apparent from the excreta. Wherever birds 

 roost in numbers, pellets or excreta or both may be gathered, 

 and when analyzed will give results scarcely less valuable 

 than those obtained by dissection, with the advantage that 

 there is no sacrifice of bird life. 



A study of the food of nestlings is less difficult and on the 

 whole more satisfactory. Both the kind and the quantity 



may be accurately determined without injuring so much as 

 a feather. 



If the nest is on or near the ground, a small neutral-colored 

 tent may be set up beside it as near as you please, into which 

 you may retire, and, by watching the progress of affairs 

 through a small u peep-hole,'' fill your note-book with an ac- 

 count of the rations that are consumed. If on the ground the 

 nest and young may be transferred to a sunken pail for better 

 observation, as shown in the bobolink photographs herewith. 

 It usually happens, however, that the nest is not in a position 



