794 REPORT OF STATE GEOLOGIST. 



The young have a greater expanse of wing than the adults, and have 

 not the white head and tail. They do not assume perfect plumage 

 until the third year. The first year they are black, and are known 

 as the Black Eagle, also "Washington Eagle." The second year, they 

 are commonly called "Gray Eagles." It is well to recall that this and 

 the Golden Eagle are the only Eagles in the United States. 



The favorite food of the Bald Eagle is fish. These it picks up on 

 the beach, where they are strewn; takes by robbery from the Osprey; 

 or, when it can get them in no other way, catches itself. February 

 24, 1891, Mr. E. Deane saw one of them fishing at English Lake. It 

 poised in the air, after the manner of a Kingfisher, sustaining itself 

 by rapid vibration of its wings, then suddenly "let go" and fairly dived 

 to the water. This was repeated twice. Failing in procuring fish, it 

 preys upon all kinds of waterfowl. They also eat lambs, small pigs 

 and poultry. Mr. E. J. Chansler informs me of a Bald Eagle that 

 was killed in Knox County, October 1, 1896, which had killed two 

 lambs. Mice and other rodents form an important article of their 

 food, and, all in all, they are considered to belong to that- class of 

 rapacious birds whose lives are mostly beneficial. 



SUBFAMILY FALCONING. FALCONS. 

 78. GBNUS FALCO LINN^IUS. 



a 1 . Only first primary with inner web emarginated; first quill longer than the 

 fourth; tarsus shorter than middle toe, and scarcely feathered below the knee; 

 wing over 11.00. Subgenus RHYNCHODON Nitzsch. 



F. peregrinus anatum (Bonap.). 141 

 a 2 . Two outer primaries with inner webs emarginated ; first quill shorter than the 



fourth. 



b l . Basal joints of toes with small hexagonal scales; tarsus about equal to mid- 

 dle toe. Size small; wing, 9.00 or less; sexes unlike. 



Subgenus ^ESALON Kaup. F. coluxnbarius Linn. 142 

 b z . Basal joints of toes covered with transverse plates; tarsus longer than middle 

 toe; size small, wing 8.00 or less; sexes different. 



Subgenus TINNUNCULUS Vieillot. F. sparverius Linn. 143 



Subgenus RHYNCHODON Nitzsch. 



*141. (356). Falco peregrinus anatum (BONAP.). 



Duck Hawk. 



Adult. First and second wing feathers equal and longest. Top 

 of head, black, decidedly darker than back; chest, creamy-buff, 

 buffy-white, or pure white, often unspotted, never very heavily 

 spotted with blackish. Immature. Lower parts streaked with 

 dusky. In Peale's Falcon, the top of the head is dark slaty, uniform 

 with back; chest, heavily spotted with blackish. 



