302 FIELD MUSEUM OF NATURAL HISTORY -ZOOLOGY, VOL. IX. 



weeds and grass, usually in a marsh. The eggs are three (rarely 4) 

 in number, pale olive gray (sometimes buffy white), marked and 

 blotched with chocolate brown, and measure about 1.85 x 1.30 

 inches. 



"Rather common summer resident in this portion of the state, 

 breeds in the numerous small reedy lakes." (Nelson, Birds N. E. 111., 

 1876, p. 147.) " Although the larger part are migratory, a good many 

 still nest within the state." (Kumlien and Hollister, Birds of Wiscon- 

 sin, 1903, p. 12.) 



26. Sterna hirundo LINN. 

 COMMON TERN. 



Distr.: Ranges throughout eastern North America, breeding nearly 

 throughout its range from Florida to the Arctic ocean; winters from 

 Virginia southward. 



Adult in summer: Bill, red, broadly tipped with black; feet, red; 

 crown, black; upper parts, pearl gray; under parts, pale ashy gray; 

 feet, orange red. 



Adult in winter: Forehead and crown, white or grayish white; 

 under parts, white; bill, blackish. Immature specimens have the 

 upper parts mottled with buff or pale brown. The outer web of outer 

 tail feather is darker than the inner web at all seasons. 



Length, about 15; wing, about 10.30; tail, 5.50; tarsus, about 

 75; bill, 1.45. 



Common Tern. 



The present species is not uncommon at times on Lake Michigan 

 during the migrations, and a few remain to breed in Wisconsin. The 



