222 NORTH AMERICAN BIRDS. 



different from the adult (?). Length 23.00-27.00 ; extent about 54.00 ; wing 16.50- 

 17.50, tail 7.50-8.50, culmen .90-.95, tarsus 3.00, middle toe 2.90. Nest a hollow in 

 stump, log, or tree-trunk, or secluded spot among undergrowth of woods. Eggs 

 1-2, 3.09 X 2.01, ovate or broadly elliptical-ovate, similar in coloration to those of 

 Cathartes aura, but usually more sparsely marked. Hab. Whole of tropical and 

 warm-temperate America, south to Argentine Republic and Chili, north regularly 

 to North Carolina and lower Mississippi Valley, irregularly or casually to Maine, 

 New York, Ohio, Indiana, Illinois, Dakota, etc. (Apparently wanting in western 

 Mexico and California) 326. C. atrata (BARTR.). Black Vulture. 



FAMILY FALCONID^E. VULTURES, FALCONS, HAWKS, EAGLES, ETC. 



(Page 218.) 



Genera. 



a 1 . Outer toe not reversible ; claws graduated in size from the largest (that of hind- 

 toe) to the smallest (that of outer toe), broader and (except in Elanus) 

 grooved on under side. 



b l . Nostril not circular, nor linear and oblique, with the upper end the posterior 

 one, nor with central bony tubercle. (Subfamily Accipitrince.') 



c\ Tail deeply forked Elanoides. (Page 224.) 



c 2 . Tail not deeply forked. 



d 1 . Wing not more than 18.00. 

 e l . Tarsi naked in front. 



f l . Front of tarsi covered with minute roundish scales ; claws 



not grooved beneath Elanus. (Page 224.) 



/*. Front of tarsus covered with large transverse scutellae; 



claws grooved beneath. 

 g 1 . Cutting-edge of upper mandible notched. 



Ictinia. (Page 225.) 

 g 3 . Cutting-edge of upper mandible not notched. 



h\ Tip of upper mandible produced into a conspicu- 

 ous lengthened hook. 



Rostrhamus. (Page 225.) 



A a . Tip of upper mandible not produced into a con- 

 spicuous lengthened hook. 

 i 1 . Face encircled by a "ruff" of short, stiffened, 

 compact feathers, as in the Owls. 



Circus. (Page 226.) 

 i*. Face not encircled by a ruff. 



y 1 . Tail decidedly more than two-thirds as 



long as wing. 



A' 1 . Depth of bill at base not decidedly 

 less than chord of culmen ; mid- 

 dle toe equal to or longer than 



