46 NEW YORK STATE MUSEUM 



as shown by the investigation of Charles Darwin. These beneficial insects 

 are destroyed as well as the injurious ones by many of our native birds, 

 ground beetles and tiger beetles especially being destroyed by such ground 

 feeders as the Crow, Blackbird, Robin and Bluebird ; the parasitic hymen- 

 optera by the flycatchers and to some extent by other species like the 

 vireos, warblers and kinglets. The earthworm and ground beetles are, 

 unfortunately, a large percentage of the food of the Robin while he is not 

 devouring fruit of some kind. 



Dispersal of injurious plants. The especial harm done in this manner 

 may be attributed to such species as the Downy woodpecker, Hairy wood- 

 pecker, Robin, Cedarbird and to a less extent to others which feed on the 

 fruit of the poison ivy, poison sumac, or other injurious plants and disperse 

 their seeds broadcast over the country on the roadsides, fence rows and 

 lake shores. 



THE ECONOMIC VALUE OF BIRDS 



Destruction of insects. As intimated in various connections hereto- 

 fore, the main value of birds is in holding tree and crop enemies in check. 

 Modern methods of fighting injurious insects seem, in some cases, to render 

 the aid of birds unnecessary, but the special value of the birds' work con- 

 sists in attacking insect pests which are not reached by poison spray and 

 at seasons of the year when spraying is not practised, thereby preventing 

 outbreaks which otherwise would cause great destruction and expense. 

 There can be no doubt that the hordes of migrating warblers attacking 

 plant lice, which can not be controlled by poison, and other injurious species 

 early in the season, thereby destroying the mother insect from which 

 innumerable progeny would later result, are of inestimable value. In fact, 

 insect scourges can never make great headway when the proper enemies 

 are at hand. Next after weather, parasites and predaceous beetles, birds 

 are the most efficient force in preventing outbreaks of insects. The almost 

 incredible voracity of birds and the rapidity of their digestive process, 

 caused by their high temperature, rapid circulation, activity and generally 

 high-strung mode of life, inevitably results in the consumption of large 



