204 THE GYPSY MOTH. 



perature and supply the tremendous waste of the tissues 

 caused by this activity a great quantity of food is necessary. 

 Excellent provision is made by nature for the rapid digestion 

 and assimilation of a great amount of food. In August, 

 1895, two young crows were confined at the experiment 

 station in Maiden, and observations were made on their feed- 

 ing habits. The time from the entrance of the food into the 

 mouth to the first voidinsf of excreta containino- remains of 

 the food eaten was usually about one and one-half hours. It 

 is probable that digestion is still more rapid in the smaller 

 insect-eating birds.* The common titmouse or chickadee 

 (Parus atricapillus) is one of the smaller birds of New Eng- 

 land, yet the good accomplished by it in destroying the eggs 

 of insects injurious to orchard and forest trees is almost 

 beyond belief. I have given elsewhere an estimate, based 

 on careftil observations and dissections, that in twenty-five 

 days one of these birds will destroy 138,750 eggs of the 

 canker-worm moth (Aiiisopteryx pometaria) .■\ 



Prof. Samuel Aughey, who fed confined plovers on in- 

 sects, found that they would eat on an average 202 locusts 

 and other large insects per day.| 



Professor Trcadwell fed to a young robin in twelve hours 

 forty-one per cent, more than its own weight in worms. The 

 same bird consumed nearly half its own weight of beef in a 

 day.§ 



At this rate a man would eat daily about seventy pounds 

 of meat. Because of their enormous appetites, birds are 

 most potent factors for good or ill. It is well known that 

 crows and blackbirds destroy vast quantities of grain for a 

 short season when they swarm upon the fields ; but their 

 services in destroying injurious insects are not generally 

 recognized. 



* According to Maynard the indigestible remains of food are excreted by the cedar- 

 bird in one-half hour after eating. (See " Birds of Eastern North America," C. J. 

 Maynard.) 



t Bulletin on " Birds as protectors of orchards," Massachusetts Crop Report, 

 July, 1895, published by the Massachusetts State Board of Agriculture. 



X First report United States Entomological Commission, 1877, page 343. 



§ "Birds of New England," by E. A. Samuels, page 159. The paper on this 

 subject was originally read by Professor Treadwell before the Boston Society of 

 Natural History. 



