THE COMMON TEEN AND AECTIC TEEN 



{Sterna hirundo and S. arctica) 



In spite of the dissimilarity of their appearance, the Terns 



and Gulls are closely related to the Plovers and Sandpipers, 



being probably the most highly specialised forms of the 



great natural group which comprises the Plovers, the 



Auks, the Petrels, the Cranes, the Bustards, and the Eails. 



The Terns rank among the most graceful of birds, and are 



indeed charming ornaments to the wild shore and the restless 



sea. They not only frequent the coast, but may often be met 



with considerable distances inland, and some species even 



prefer the marshes to the shore. The Common Tern is by no 



means so abundant or so widely distributed as its name seems 



to imply. It is a bird of passage to this country, arriving 



late in spring, and departing southwards in autumn to the 



seas round sultry Africa. If the weather is fine and the 



season a moderately early one, the Common Tern arrives at 



its usual summer haunts by the end of April, but in backward 



years not until early May. In most places where the shore 



is suited to its needs the Common Tern may be found. It 



loves the various groups of low islands and ocean rocks that 



occur so frequently round our northern coasts, and it never 



makes its colony on the mainland if an island can be had 



instead. Terns are birds of the air and justly deserve their 



name of " sea swallows." Upon the ground they are awkward, 



and they seldom attempt to walk, because, like the Swallows, 



