164 TERNS 
II. Wing over 13°00. 
A. Wing 15°00 or over; outer primary mostly gray. 64. Caspian TERN. 
B. Wing under 15°00; inner half of inner web of first primary white. 
65. Roryau Trern. 
Fia. 79. First primaries of adult Terns, seen from below: (a) Caspian Tern; 
(b) Royal Tern; (c) Common Tern; (d) Arctic Tern; (¢) Roseate Tern. 
63. Gelochelidon nilotica (Linn.). GULL-BILLED TERN. Ads. in sum- 
mer.—Top of head and nape black; back and wings pale pearl-gray; outer 
web of outer primaries silvery; tip and shaft part of inner web darker; 
inner part of inner web, except for a narrow margin at end of feather, white; 
tail white, slightly forked, the middle feathers grayish; underparts white; 
bill and feet black, the former rather short and stout. Ads. in winter.—Sim- 
ilar to the above, but top of the head white, auriculars grayish, and a space 
in front of the eye blackish. L., 14°50; W., 12°00; T., 5°50; B., 1°40; depth of 
B. at base, °50. 
Range.—Nearly cosmopolitan. Breeds in N. Am. on coasts of Tex., 
La., N. C., Va. (formerly to N. J.), and in the Bahamas; wanders casually 
to Maine and Ohio; winters in s. Mex., s. Guatemala, and from Brazil s. to 
Patagonia and Chile. Breeds also in Europe, Asia, and Australia, and winters 
s. to n. Africa. 
_ Washington, casual in autumn, no recent records. Long Island, A. V. 
in summer. 
Nes, of shells and pebbles, on beaches. Eggs, 3-5, rather uniform buffy 
white, with numerous distinct and obscure chocolate markings, 1°80 x 1°30. 
Date, Corpus Christi, Tex., Apl. 30; Cobb’s Is., Va., May 30. 
