No. 4.] BIRDS AND CATERPILLARS. 331 



Rose-breasted grosbeak. Yellow warbler. 



Indigo bunting. American redstart. 



English sparrow. Catbird. 



Scarlet tanager. Brown thrasher. 



Red-eyed vireo. Chickadee. 



Yellow-throated vireo. Robin. 

 Bluebird. 



Assuming that our observations have proved that birds eat 

 hairy caterpillars, it may be interesting to inquire why this 

 fact has not been previously noticed. It will be seen at once, 

 by one who makes a study of the subject, that the error 

 which has been so long persisted in arises, first, from a lack 

 of careful observation. 



It is not strange that the cuckoos should have been known 

 for years to feed on hairy caterpillars. The cuckoos are 

 sizable birds ; they are not shy, and as they feed on the 

 larger caterpillars when those insects are full grown, and as 

 both cuckoos and caterpillars are common in the vicinity of 

 dwellings, their habits in this respect could not escape the 

 most casual observer. But to observe the habits of shy 

 birds, such as the crows and jays, which feed on the larger 

 caterpillars, is much more difficult ; and to learn the feeding 

 habits of the smaller birds, which feed mainly on the minute 

 larvae soon after these larvae have hatched from the esfET, is 

 still more difficult. Reliable observations of this class can 

 be made only by trustworthy and skilled observers, who can 

 devote time to the task. 



But it may be asked, Why have not those who have dis- 

 sected the stomachs of the birds discovered that they were 

 eating hairy caterpillars to a considerable extent ? To this 

 it may be answered that up to the present time most of the 

 knowledge that has been gained in regard to the destruction 

 of hairy caterpillars by birds has been gained from stomach 

 examinations, and it is by stomach examinations mainly that 

 light has been thrown on this question. Yet he who 

 examines the stomachs of small birds labors under many 

 difiiculties in determining the specific character and quantity 

 of food of this class. Minute caterpillars are speedily re- 

 duced to a pulpy mass in the bird's stomach. While the 

 field observer may readily identify the small tent caterpillars, 

 for instance, on which the birds are feeding, and even count 



