42 



KEY TO THE BIHDS OF EASTEUN NORTH AMERICA. 



J' 



Forster's Tern. Winter. 



Roseate Tern. 





Common Tern. 



%,,: 



.\(lult Tern.-: (except 

 and season. 



Least Teru. Gull-bille.l Tern. 



the No<idv) l.ave tl.e top of the head entirely black, part of the year, varying with age 



