THE ECONOMIC VALUE OF BIRDS 



haustive and exceedingly thorough investigation of 

 the feeding habits of the wild birds that frequent 

 the fields and forests. The reports of the economic 

 ornithologists herein given are almost as surprising 

 as the sad records given by the entomologists in the 

 Year Book. We learn that birds, as a class, con- 

 stitute a great natural check on the undue increase of 

 harmful insects, and furthermore that the capacity 

 for food of the average bird is decidedly greater in 

 proportion than that of any other vertebrate. 



Some Useful Birds. — Most people who have made 

 the acquaintance of our common birds know the 

 friendly little Chickadee, which winter and summer 

 is a constant resident in groves of deciduous trees. 

 It feeds, among other things, on borers living in the 

 bark of trees* on plant lice which suck the sap, on 

 caterpillars which consume the leaves, and on cod- 

 ling worms which destroy fruit. One naturalist 

 found that four Chickadees had eaten one hundred 

 and five female cankerworm moths. With scalpel, 

 tweezers, and microscope these moths were examined, 

 [105] 



