NATURAL ENEMIES. 203 



Natural Enemies of the Gypsy Moth. 



Insect-eating Birds. 

 Since the work of preventing the spreading and securing 

 the extermination of the gypsy moth in Massachusetts was 

 placed in the hands of the Board of Agriculture in 1891, 

 particular attention has been paid to the natural enemies of 

 the moth. All persons employed in the work have been 

 instructed to watch for enemies or parasites, and keep a 

 record of all observations made. In accordance with these 

 instructions, voluminous notes now covering many hundred 

 pages have been made. Many enemies of the moth have 

 been studied both under natural conditions and in confine- 

 ment. Search has been made through European literature 

 for information in regard to the enemies of the moth abroad. 

 Much information bearing upon the subject has also been 

 obtained by foreign correspondence. In apportioning the 

 preparation of the report on the natural enemies, the task of 

 preparing a report on the birds was assigned to me. My 

 colleague, Professor Fernald, will treat of tlie other enemies 

 of the moth. 



The Usefulness of Birds as Insect Destroyers. 



The subject of birds versus insects is a most important 

 one. The influence of birds on the agriculture of a country 

 is incalculable. The protection or destruction of native birds 

 and the introduction of foreign species are subjects worthy 

 of the most thoughtful consideration of the agricultural 

 department of any government. 



Land birds fulfil their part in many ways in preserving 

 the balance of nature, but chiefly by doing much toward 

 holding in check the increase of the insect world, which, if 

 unrestricted, would swarm over and devastate the earth. 



Birds are among the most highly organized of vertebrate 

 animals. In them we find the greatest activity and the 

 highest temperature of the blood. To maintain this tem- 



