110 



USEFUL BIRDS. 



to tree culture cecropia has no equal in some portions of the 

 prairie country, and that its large caterpillars often defoliate 

 entire groves. Mr. W. C. Colt, who has had experience in 

 raising trees in Dakota, told me that the caterpillars of this 



Fig. 37. The larva of the cecropia moth, a destructive leaf-eating insect, 

 held in check by birds. 



and other large species were terribly destructive there. As 

 groves and orchards became established, however, and arbo- 

 real birds spread over the country, these caterpillars were 

 reduced to a state of comparative harmlessness. There is 

 good reason, therefore, for the belief that the caterpillars so 

 commonly eaten by practically all arboreal birds would, to- 

 gether with the borers, destroy all the forests were the birds 

 to be banished from their chosen haunts. 1 



1 The latter part of this chapter consists of revised portions of several papers 

 by the author, originally published by the Massachusetts State Board of Agri- 

 culture. 



