KEY TO THE FAMILIES OF BIRDS 



48 



B. Bill hooked and with a distinct membrane (cere) at the base, extend- 

 ing past the nostrils ^ — 



— Head fully feathered, or nearly so XXIX. Hawks, etc. 



— Head and neck naked or merely covered with hair" 



XXX. Vultures. 



B. Bill without cere, and in most cases not strongly hooked. (C.) 

 C. Hind toe short, small, inserted above the level of the others ; ' front 

 toes with a plain webbing at base ; ' bill generally stout, short, 

 and horny ; i'' outer primaries of the wing curved and usually 

 stiff ; ground-living game birds — 



— Wing, 4-1.5 inches long XXXIV. Grouse, etc. 



— Wing over 10 inches long XXXIII. Turkeys. 



C. Bill straight, the horny tip separated from the base by a narrow por- 

 tion ; nostril opening beneath a soft, swollen membrane ii (hard 

 and somewhat wrinkled in mounted birds) XXXI. Pigeons. 



C. Bill stout, straight, longer than the head ; i^ feet with the outer 

 and middle toes grown together for half their length ; ^ tarsus 



very short XXIII. Kingfishers. 



C. Bill very slender and long ; " the smallest of birds ; wings not over 



2; long in our species XIX. Hummingbirds. 



C. Bill with the top ridge or culmen very short, but the gape both 

 wide and deep, reaching about to the eyes ; ^^ gape usually three 

 times as long as the culmen. (0.) 

 C. Not as above. (D.) 

 D. Inner secondary quills lengthened, nearly as long as the primaries in 

 the closed wing ; i^ nail of hind toe much lengthened and generally 

 straightened ; " the ground birds called "larks." (N.) 

 D. Inner secondaries not especially lengthened ; the first primary 

 short,i8 never more than | as long as the longest, usually less than 

 J as long, sometimes barely noticeable on the under edge of the 

 wing." (J.) 

 D. With neither the inner secondaries very much lengthened nor the 

 first primary much shortened ; the first primary always more than 

 I as long as the longest quill. (E.) 

 E. Bill broad, depressed, wider than high at base, usually tapering to 

 a point, which is often abruptly hooked. 2' (H.) 





^ 



