116 USEFUL BIRDS. 



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 noteworthy that most of 

 the more observing writers give the Cuckoo as an exception 

 to their established (?) rule that birds do not eat hairy cat- 

 erpillars. It is not strange that the Cuckoos should have 

 been known for years to feed on such caterpillars. The 

 Cuckoos are sizable birds ; they are not very 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 it is much more 

 difficult to observe the habits of shy birds, such as the Crows 

 and Jays, which feed on the larger caterpillars ; and to learn 

 the feeding habits of the smaller birds, which feed mainly 

 on the minute larvae soon after these have hatched from 

 the egg, requires the most painstaking care. Most of the 

 caterpillars that are eaten by the smaller birds are taken 

 when the larvae are so small and have done so little injury 

 that they have not become apparent to common observa- 

 tion. Thus they are destroyed before most people even 

 suspect their presence ; while, per contra, those which escape 

 the smaller birds and grow to a large size are seldom eaten 

 in this stage except by a few species of the larger birds, 

 which, like the Cuckoo, Catbird, Jay, and Crow, bolt them 

 whole. Thus another source of the prevalent opinion is ex- 

 plained. A few smaller birds, such as the Titmice, Vireos, 

 and Orioles, tear caterpillars open, and thus avoid swallowing 

 the head, skin, and hair. Sometimes, when the adult birds 

 put such caterpillars down the throats of their well-grown 

 young, the little birds will reject them. A young Oriole put 

 its foot upon the protruding end of a larva, and pulled the 

 wriggling creature back to daylight. There is no doubt 

 that when these caterpillars grow large many small birds 

 experience the same difficulty in eating them whole that we 

 should encounter were we attempting to swallow the bones of 

 a fish. So, when larvae have grown large, and are covered 

 with stiff spines or hairs, only the larger birds or the most 



