42 



KEY TO THE BIRDS OF EASTEItX NORTH AMERICA. 



Forstei'V Tern. Winter. 



Roseate Tern. 



Common Tern. 



Least Tern. Gull-billcd Tern. 



AduU Terns (except the No«lily) liave tlie top ol' tlie liead entirely l)lack, i)art of the year, varyin},' witli age 

 and season. 



