KEY TO FAMILIES 



119 



very long and pointed, the outer feathers being much the longest; 

 toes webbed. Adult Gulls and Terns are usually pearl-gray above, 

 white below ; Jaegers and most young Gulls are dark. 

 A. Bill hooked and hawklike. 



a. Bill with a naillike hook, its base with a scaly shield; plumage 

 dark; central tail-feathers longest. (Fig. 23, a). . . . Family 

 Stercorariidce: SKUAS and JAEGERS, p. 150. 



6. Hook continuous with bill, no scaly shield, tail-feathers usually 

 of about equal length (Fig. 23, 6) .... Subfamily Larince: 

 GULLS, p. 152. 



Fio.24. 



FIG. 25. 



B. Bill not hooked. 



a. Bill straight, usually slender and sharply pointed; tail usually 



more or less forked. . . . Subfamily Sternina: TERNS (Fig. 24), 



p. 162. 

 6. Bill thin and bladelike, the lower mandible longer than the 



upper (Fig. 25). . . . Family Rynchopidce: SKIMMERS, p. 172. 



FIG. 26. 



Order III. Tubinares. ALBATROSSES, PETRELS, and FULMARS. 



Gray, sooty, or black and white sea-birds; living, except when nesting, 

 well off shore; flying low, often skimming the waves. Nostril-openings 

 tubelike; bill hawklike, its 'hook' often prominent; front-toes webbed, 

 hind-toe small or absent ; wings long and pointed ; tail short. 



A. Size very large, nostril-tubes separated, on sides of bill (Fig. 26, a). 



. . . Family Diomedeidce: ALBATROSSES, p. 172. 



B. Size smaller, nostril-tubes joined on top of bill (Fig. 26, 6). ... 



Family Procellariidce: PETRELS, FULMARS, SHEARWATERS, p. 173. 



