42 



KEY TO THE BIRDS OF EASTE[;N NORTH AMERICA. 



Forster's Tern. Winter. 



Roseate Tern. 



Common Tern. 



^;ji:- 





Least Tern. , Gull-billefl Tern. 



Adult Ternn (except tlie Norldy) have the top (if tlie head entirely black, part of the year, varying with .age 



