152 BIEDS. 



9. STERNA, Linnreus. COMMON TERNS. 



1. S. hirundo, Auct. COMMON TERN. SEA SWALLOW. 

 WILSON'S TERN. Bill red, blackening towards tip; tail 

 mostly white; outer web of outer feather darker than 

 inner; L. 14 (13 to 16); W. 10 (9 to llf); T. 6 (5 to 

 7.) Coasts of Europe and America; abundant. (/S. 

 wilsoni, Lawr.) 



2. S. forsteri, Nuttall. FORSTER'S TERN. Larger; 

 tail longer and wings shorter; inner web of outer tail 

 feather darker; W. 9 to 10; T. 6| to 8. N. Am., 

 common. 



3. S. macrura, Naumann. ARCTIC TERN. Bill carmine 

 throughout; plumage as in hirundo, but darker below; 

 L. 14 to 17; W. 10 to 12; T. 5 to 8; smaller than 

 hirundo, but tail proportionally much longer. Northern 

 regions, S. to U. S. 



4. S. paradisea, Auct. ROSEATE TERN. Bill black, 

 usually orange at base below; mantle very pale; some- 

 what rosy -tinted below; L. 12 to 16; W. 9 to 10; T. 5 

 to 8. Atlantic Coast, abundant. (S. dougalli, Mont.) 



5. S. port/andica, Ridgway. PORTLAND TERN. Near 

 the preceding, but mantle as in hirundo; the rump 

 white instead of pearly; feet blackish; under parts pure 

 white; L. 12; W. 9f ; T. 5 or more. Lately discovered 

 in Maine and Mass.; but two specimens known. 



6. S. superciliaris, (Vieill.) var. antillarum, (Lesson) 

 Coues. LEAST TERN. Bill yellow, usually tipped with 

 black; a white frontal crescent between cap and bill; 

 shafts of two or more outer primaries black above; very 

 small; L. 8 or 9; W. 6; T. 2 to 3. U. S., chiefly 

 abundant coastwise. 



