Birds of the Caucasus. 37 



Larus ridibundus. 



The Black-headed Gull is found throughout the Caucasus, 

 except on the mountains. It is probably a resident. 



Larus minutus. 



The Little Gull passes the Caucasus on migration. 



Sterna caspia. 



The Caspian Tern is seen on the Caspian Sea during 

 autumn. 



Sterna cantiaca. 



The Sandwich Tern is seen in autumn on the Caspian Sea. 



Sterna anglica. 



The Gull-billed Tern is frequently seen in the Caucasus in 

 summer and autumn. 



Sterna hirundo. 



The Common, Tern is very abundant in the valleys of the 

 Terek and the Kuban. It is probably a resident. 



Sterna minuta. 



The Lesser Tern is very abundant in the valleys of the 

 Caucasus. 



Sterna nigra. 



The Black Tern is common in the valleys of the Terek and 

 the Kuban during summer. 



Sterna hybrida. 



The Whiskered Tern is very common in tlie valleys of the 

 Terek and the Kuban. 



Sterna leucoptera. 



The White-winged Black Tern is often seen during summer 

 and autumn in the valleys of the Terek and the Kuban. 



