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of food for the stomach and also to the rapid digestion of the food by 
the bird, it is impossible in many cases to identify a large part of the 
stomach’s contents. It is also very difficult to get by stomach exam- 
inations alone an accurate estimate as to the relative amounts of the 
component parts of the food taken by a species. CU. J. Maynard says 
that food can be assimilated and digested by the cedar bird and the 
residue passed through the alimentary canal within half an hour. The 
process of digestion in the crow probably does not consume more than 
an hour and a half. Much of the insect food is so finely comminuted 
in the stomach of the bird in a few minutes that it becomes unrecog- 
nizable. Certain insect-eating birds eat only the internal parts of 
certain insects, casting aside the external parts, which only could be 
recognized by one examining the stomach of the bird. This is espe- 
cially the case when the food consists of hairy caterpillars. The 
smaller birds eat many of the younger and smaller hairy caterpillars, 
swallowing them whole. It is very difficult for one depending on 
stomach examinations alone to recognize these soft-bodied, minute 
caterpillars in the stomach of the bird, where they are soon transformed 
into a shapeless mass. As the caterpillars become larger the birds 
attack them, killing them by repeated blows of the beak, tearing them 
open and eating out certain portions of the viscera or taking out all the 
body contents, rejecting the head and skin. This has often come under 
the writer’s personal observation, and many instances are now on record 
where this method of feeding has been observed. Mr. I. H. Mosher 
records an instance where a vireo took brown-tail caterpillars, swallow- 
ing the sinaller ones, pulling the larger ones to pieces, and swallowing 
some of the pieces. In eight minutes she destroyed 15 in this manner. 
Another bird of the same species was seen to destroy 73 gypsy cater- 
pillars in forty minutes. The larve were large and the bird held them 
under its foot, pulling out certain inner parts, eating them, and dis- 
carding the rest. This is a common practice with the chickadees and 
tanagers. The warblers and certain other birds have the same habit. 
This habit is not constant, but quite general. A bird may tear one 
caterpillar to pieces, eating some of the pieces, swallow another whole, 
and take a portion of the viscera of the next. 
The crows, jays, and titmice kill a great many caterpillars and pup 
which they do not eat. They are first beaten with the beak and then 
dropped by accident or in sport and left where they fall. Therefore we 
come to see the necessity of field observations to supplement dissection. 
He who examines the stomach contents of the birds without knowledge 
of the locality which the birds frequent in life and the opportunities 
which they have for obtaining different kinds of food, or without an 
insight into their feeding habits, may fall into grave errors. 
Field observations will help the laboratory worker in another way. 
He may be enabled, by noting the feeding habits of the birds, to iden- 
