EELATION TO AGRICULTURE 49 



Added to this is the value rendered in the 

 destruction of weeds and rodentsi. The daily 

 consumption of weed seeds alone amounts to thou- 

 sands of tons. The value of weeds, however, can 

 only be measured by the amount of labor and 

 time it takes the farmer to eradicate them. The 

 cash thus saved must amount to a large total. 



Useful birds of prey average about two noxious 

 rodents a day as food. If a field-mouse is ca- 

 pable of inflicting only one cent's worth of dam- 

 age upon farm crops, every mouse-eating bird 

 will consume about seven dollars ' worth of mice a 

 year. Allowing to a hawk a life span of ten 

 years, then each such bird must potentially be 

 worth seventy dollars to the United States. 



In the northeastern States there are at a low 

 estimate two birds residing on every acre of 

 land. We shall call forty acres the average farm, 

 thus allowing eighty birds to each farmer. Every 

 bird, if it lives for five years, is worth, according to 

 McAtee's figures, fifty cents as a destroyer 

 of insects. As a consumer of weed seeds let us 

 suppose it is valued at half that. This will give 

 the birds an average value of seventy-five cents 

 apiece, or a total of sixty dollars for the farm. 



On every two farms there should be at least 

 one beneficial bird of prey, a hawk or an owl, 

 whose value alone is seventy dollars, or thirty- 

 five dollars to one farm. Added to the above, 

 this gives us a total of ninety-five dollars for 



