JAN., 1909. BIRDS OF ILLINOIS AND WISCONSIN CORY. 155 



Thighs, tinged with deep rufous, with numerous bars. 



Archibuteo ferrugineus. 

 Ferruginous Rough-legged Hawk. 

 See No. 163. 



GROUP 7. Wing, over 21 inches long. (Eagles.) 



General plumage, fuscous brown ; tarsus, entirely feathered ; head 

 and terminal portion of tail, never white. Immature birds have the 

 basal half or more of the tail feathers white. Aquila chrysaetos. 



Golden Eagle. 

 See No. 165. 



Tarsus, not entirely feathered; head and tail, more or less white 

 in old birds ; younger birds have no white on head, and very little on 

 the tail, but the partly bare tarsus will always distinguish immature 

 birds of this species from the Golden Eagle ; fully adult birds have the 

 head, neck, and tail entirely white and the bill yellow. 



Haliaetus leucocephalus. 

 Bald Eagle. 

 See No. 166. 



Family STRIGID^. Owls. 



Radiated disk of feathers surrounding the eye; plumage, soft; 

 toes, armed with strong curved talons ; bill, hooked. 



* GROUP 1. Wing, less than 8.50 inches long. , 

 SECTION 1. Toes, thickly feathered. 



Wing, less than 6.10; upper plumage, dark cinnamon brown, 

 more or less marked with white; under parts, whitish, streaked .with 

 brown ; adult birds have much white about the face ; immature birds 

 have the face dusky, but the eyebrows white. Glaux acadicus. 



Saw-whet Owl. Acadian Owl. 

 See No. 179. 



* For directions for measurement, see page 21. 



