TERNS. 81 



under parts white ; tail light pearl -gray, the outer feather darker toward the 

 end, where the inner web is always darker than the outer ; bill dull orange, 

 the end third blackish ; feet orange. Ad. in winter. Similar to the above, 

 but head white, more or less washed with grayish or spotted with black, a 

 large black spot on the side of the head inclosing the eye ; bill mostly black ; 

 feet brownish. Im. Similar to the preceding, but the back and wings more 

 or less mottled or washed with light brownish, and the tail much shorter. 

 L., 15-00 ; W., 10-25 ; T., T'OO ; Tar., 90 ; B., 1-50. 



Range. Of more or less general distribution throughout North America, 

 breeding in the east locally from Texas northward through the Mississippi 

 Valley to St. Glair Flats and Manitoba recorded from Lake Mistassini ap- 

 parently not breeding on the Atlantic coast north of Virginia, but wandering 

 irregularly to Massachusetts. 



Washington, rare and irregular T. V. Long Island, rare T. V. in fall. 



Nest, of seaweed, flags, or weeds on a slight elevation in grassy marshes. 

 Eggs, three, very variable, olive-gray, or olive brownish ashy, more rarely 

 whitish or buff, heavily marked with chocolate, T80 x 1-30. 



Dr. Brewer, writing of Mr. Ridgway's experience with this species 

 on Cobb's Island, Virginia, where it was found breeding in numbers, 

 says : " It was only less abundant than the Anglica [= nilotica\, and 

 quite as numerous as the hirundo, frequenting especially grassy 

 marshes, in which it nests. He found it pre-eminently a marsh Tern. 

 It nested in company with, or in close proximity to, colonies of the 

 Black-headed Gull. It could be readily distinguished from the Com- 

 mon Tern, which it closely resembles when on the wing, by its grating 

 monotonous note, which very closely resembles one frequently uttered 

 by the Loggerhead Shrike" (B. B., and R.). 



70. Sterna hirundo Linn. COMMON TERN; WILSON'S TERN; SEA 

 SWALLOW (see Fig. 7). Ad. in summer. Whole top of the head black ; back 

 and wings pearl-gray ; inner border of inner web of outer primaries white, 

 except at the tip (Fig. 61, c) ; throat white ; breast and belly pale pearl-gray ; 

 tail white, the outer webs of the outer feathers gray or pearl-gray ; bill red at 

 the base, the end third black ; feet orange-red. Ad. in winter. Similar to 

 the above, but front part of the head and under parts white: bill mostly 

 black. Im. Similar to the preceding, but the back more or less washed or 

 mottled with light brownish ; lesser wing-coverts slaty gray, and tail much 

 shorter. L., 15-00 ; W., 10-25 ; T., 5-50 ; Tar., -75 ; B., 1-40. 



Remarks. The Common Tern is closely related to Forster's Tern and also 

 to the Arctic Tern. From the former it is to be distinguished by the color of 

 the long outer tail-feathers. In the Common Tern the outer web of these 

 feathers is always darker than the inner web; in Forster's Tern the inner 

 web is always darker than the outer one. Adult Common Terns have the 

 breast and belly washed with pearl-gray, while in Forster's Tern these parts 

 are pure white. 



The Common Tern differs from the Arctic Tern in having the bill tipped 

 7 



