1914J Bryant: Economic Status uf I he Western Mcadoiclark 469 



Such writers have been proue to take the point of view that 

 birds were expressly made to destroy injurious insects. One 

 might just as well say that insects were created to furnish food 

 for birds. If birds should become numerous enough actually to 

 control the number of insects, they w'ould doubtless become a 

 greater pest than the insects themselves. 



Parasitic insects are not proving to be the controls which 

 their advocates have maintained they would be. And certainly 

 there are arguments which prove that birds are not the panacea 

 for all insect ills. Birds destroy many of the most beneficial 

 insects known. Some of the most injurious insects are less often 

 taken by birds. Birds, though they be in abundance, fail to 

 prevent outbreaks of injurious insects. Birds scatter weed seed 

 as well as destroy it. If there were no birds, would not other 

 factors, such as parasitism, climatic conditions, etc., soon bring 

 about a balance? Besides, cannot insect pests be more surely 

 and successfully controlled bj' artificial means, insecticides, 

 sprays, etc. ? On the other hand, is there not a saving of expense 

 in letting nature control insect ravages as far as possible ' 



All of these points deserve our consideration. They need to 

 be weighed in the balance. When all the evidence for and 

 against the utility of birds is in, a solution will be available. 

 Until that time there will always be two sides to the question. 



A partial solution of the problem is afforded by placing 

 emphasis elsewhere, thereby avoiding these two opposing sides 

 of the question. Forbes (1903) pointed out that the value of 

 birds does not lie in the fact that they discriminate and take 

 only injurious insects, but in the fact that they eat insects. The 

 place filled by birds in the economy of nature is the important 

 thing. 



Jlost life under the natural order of things is conditioned 

 very largely by its food supply : in the case of purely insectiv- 

 orous birds, by insects; in the case of in.sects, by plant life. If 

 it be true, as it appears to be, that organisms become so adjusted 

 to their food supplies that only the surplus or excess is normally 

 taken, then the importance of birds in their relation with insects 

 lies in their toll of the surplus. Since it is the excess or abnormal 

 abundance of insects that makes most trouble for the agricul- 



