DESCRIPTION. 



15. Caspian Tern. 



Length about 22 inches. Bill about 3 inches 

 long, coral-red, feet black, tail about 6 inches long, 

 slightly forked, white. Upper parts pale pearl- 

 gray, head and nape glossy-black. Lower parts 

 pure white. 



16. Common Tern. 



Length about 15 inches. Bill about ]J inches 

 long, bright vermilion-red, blackish at tip. Tail 

 about 6 inches long, forked. Upper parts pearl- 

 gray and white, head and nape black. Lower 

 parts pale lavender-gray, feet orange-vermilion. 

 Young : Crown blackish and grayish-white, back 

 pale pearl gray, bill brownish dusky, base reddish, 

 feet pale-reddish. 



17. Arctic Tern. 



Length about 16 inches. Bill about 1| inches 

 long. Tail about 7J inches long. Bill and feet 

 carmine. Upper parts pearl-gray and white, black 

 cap on head. Lower parts lavender-gray. 



18. American Black Tern. 



Length about 10 inches. Bill about 1 inch long, 

 brownish-black. Tail about 3f inches long. Upper 

 parts blackish. Lower parts black, with lower 

 tail-coverts white, legs and feet reddish-brown, tail 

 slightly forked. Young : Head, neck and loAver 



