214 BIRDS IN THEIR RELATION TO MAN 



Note. Dr. S. A. Forbes, State Entomologist for Illinois, 

 believes that if the operations of birds in Illinois were stopped 

 for a period of seven years, the entire state would be covered 

 with insects, one to a square inch. He estimates birds' value 

 to agriculture at $76,000,000 a year. 



2. Which of the above birds are clearly beneficial ? Clearly 

 harmful ? Explain your answers. 



b. Special Economic Importance of Some Birds 

 Observations. 1. Fill in the following tabulation : 



