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 ; ^'^ outer primaries of the wing curved and usually 

 stiff ; ground-living game birds — 



— Wing, 4-15 inclies long XXXI V. Grouse, etc. 



— Wing over 16 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 ^^ (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 ; i^ tarsus 



very short XXIII. Kingfishers. 



C. Bill very slender and long ; i* 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 gai)e 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 ; lo nail of hind toe much lengthened and generally 

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

 D. Inner secondaries not especially lengthened ; the first primary 

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

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

 wing.i9 (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. ^^ (H.) 



