224 ELEMENTS OF AGRICULTURE 



destructive beetles. It has also been shown that thirty 

 eeclar birds would destroy 9,000 worms during the 

 month when the cutworm caterpillar is exposed/'* 



We might add many hundred examples like the above 

 to show the great number of insects destro}^ed by birds. 

 It is very reasonable to suppose that the more birds we 

 have about, the more insects will be eaten. Professor 

 Forbes estimates the number of birds in Illinois at three 

 individuals to the acre, f In Virginia there are probably 

 as many birds to the acre as there are in Illinois, so we 

 may assume that there are three birds to each acre of 

 land in Virginia. This would give us for this State 

 something like eighty million birds. Suppose that each 

 bird destroys only one insect a day, it would mean 

 the destruction of eighty million insects. One insect 

 a day to each bird, however, is too low an estimate; 

 twenty insects to each bird would be more probable. 

 To be on the safe side, then, let us assume that two- 

 thirds of the total number of birds, or 53,000,000, 

 eat insects, and that each individual bird eats an 

 average of ten insects a day. This would mean 530,- 

 000,000 insects destroyed each day by birds. Could 

 there be a more effective way of destroying them? 

 Could we but add to the number of insect-eating birds 

 within the state of Virginia only one individual to each 

 acre of ground, it would mean the destruction of mil- 

 lions of insects, and a saving of many thousand dollars 

 to the farmers and fruit growers. Yet no efforts are 

 made to increase the number of such birds; on the con- 



•Report of Conn. Board of Agr., 1899, p. 83. 

 ilbid, p. 77. 



