INSECTS AND BIRDS. 305 



jurious. Even those that the farmer considers as 

 among his chief enemies are often found to be far more 

 useful than harmful when their food habits are studied 

 with scientific care. Whenever a bird attacks poultry, 

 fruit or grain its ravages are conspicuous. But many 

 birds may feed on the enemies of fruit, grain or poul- 

 try without attracting our attention in the least. 

 Therefore the harm that birds do is often exaggerated, 

 while the good offices they perform are either unnoticed 

 or underestimated. 



Beneficial Species. It sometimes happens that the 

 investigator finds so many factors entering into the 

 food relations of a bird that it is difficult to determine 

 whether or not the species is beneficial. But no family 

 of birds can be regarded as wholly inimical to the 

 farmer, and only a few species in any country can be 

 regarded as injurious. Species vary greatly in im- 

 portance and usefulness when looked at from the stand- 

 point of the agriculturist. Some appear to be of little 

 or no economic worth, while the services of others seem 

 absolutely essential to successful Husbandry, Horticul- 

 ture or Forestry. 



The Good that Birds Do. They are well fitted by 

 nature for their peculiar office. Their flight is remark- 

 ably swift and well sustained. Their sight is keen and 

 telescopic, and they are endowed with a tremendous 

 capacity for devouring, digesting and assimilating food. 

 The muscular exertion put forth by birds in their every- 

 day occupations is extreme. They are so energetic 

 and active that they need far more food than is re- 

 quired by mammals. It is not unusual for the growing 

 young of certain species of birds to consume daily an 

 amount of food fully equal to their own weight, and 

 the quantity eaten by many small land birds is so large 

 that when they forage in flocks on the crops of the 

 farmer they cause excessive loss; but the severity of 

 such losses only serves as an indication of the amount 

 of good that birds do in devouring the destructive in- 

 sect enemies of the same crops. 



