JAN., 1909. BIRDS OF ILLINOIS AND WISCONSIN CORY. 



461 



Cooper's Hawk. 

 Red-tailed Hawk. 



Red-shouldered Hawk. 



Illustrating comparative difference in size. 



Male: Length, 19 to 22.50; wing, 13.50 to 16; tail, 8.60 to 10; 

 tarsus, 2.50 to 3. 



Female: Length, 20.50 to 24; wing, 14.75 to 17.50; tail, 9 to 10.50; 

 tarsus, 2.75 to 3.10. 



This is the common form of Red-tailed Hawk in Illinois and Wis- 

 consin and breeds in both states. The adult may be easily recog- 

 nized by its size and rufous red tail. The immature bird has the 

 tail brownish gray with numerous bars. The large size and stout 



