94 NEW YORK STATE MUSEUM 



and measure about 2.85 by 2.2 inches. The period of incubation is 4 

 weeks or more, and the young do not leave the nest till July or the first 

 of August. When hatched they are covered with whitish down, but 

 before they are able to fly have acquired the brownish black plumage 

 as described above. 



Haliaeetus leucocephalus alascanus C. H. Leonard 



NortJiern Bald Eagle 



Eagles of the species leucocephalus inhabiting the boreal zone of North 

 America are larger than southern birds and equal or surpass the largest dimensions 

 given (wing 25, tail 13, tarsus 4, depth of bill 1.5). Many specimens from this State 

 exhibit these dimensions, and are to be assigned to the northern race. In deciding this 

 question, however, it is well for the amateur to remember that immature eagles have 

 longer wings and tails than old ones. 



Family KA.LCONIDAE 



Tlic Falcons 



Characters. Beak sharply hooked, toothed and notched, the lower 

 mandible truncate and notched near the tip; nostrils circular, high up 

 in the cere, with a central tubercle; bony eye shield projecting, of a single 

 piece; septum of the nose much ossified; palatal bone with a median keel 

 anteriorly; scapular process of the coracoid united to the clavicle; tarsus 

 shorter than tibia, more or less feathered above, its scales reticulate ; middle 

 toe long; talons strong and curved; wings long, strong and pointed; tail 

 stiff and rather short; legs stout; general build strong and muscular; the 

 plumage af tershaf ted ; basipterygoid process wanting; eyes brown in color; 

 flight swift and strong, the prey usually pursued and captured in the air; 

 courage great for the size of the birds. 



In this family the raptorial nature reaches its highest differentiation. 

 The muscular build, the length and strength of the wings, the curious 

 sculpturing of the sharp cutting edges of the beak, the powerful legs and 

 long, strong, curved talons fit the falcons admirably for their career of 

 rapine. They choose prey which is oftentimes larger and heavier than 

 themselves. Few birds can escape their powerful, sweeping flight. They 

 strike down and slaughter without trouble the swiftest flying ducks, grouse 

 and pigeons, and, with the exception of the smaller members of the family 



