68 BRITISH BIRDS. WITH THEIR NESTS AND EGGS 



true migration as in that of the present species. Long-extending flights of these 

 pretty little birds may be seen travelling over the sea past the island [Heligoland] 

 at the close of September and during the first half of October. Their movements, 

 however, are quite different from what one is accustomed to see in the case of 

 most migrants. Companies of from one to two hundred individuals travel in 

 motley throng quite low over the sea, continuously dropping to the surface to 

 pick up food. All the time, however, they rigidly maintain their western course 

 of flight and, speeding along with great rapidity, are very soon lost to sight. . . 

 While roving over the sea in all directions in search of food, they execute many 

 rapid beats with their wings, continuously displaying at the same time the peculiar 

 greyish-black colour of their under sides." 



Family LARID&. SubJamilyLARINsE. 



BLACK-HEADED GULL. 



Larus ridibundus, LINN. 



THE Black-headed Gull is a true British species, breeding in all three islands, 

 and many individuals spending the winter also on our coasts. It is found 

 nesting throughout the whole of Europe, north to the Faeroes, and across all 

 northern temperate Asia to Kamtchatka. In winter it migrates south to the Red 

 Sea, to Northern Africa and down the west coast. It finds its way also to the 

 Persian Gulf and to India, and even to the Philippine Islands, perhaps, by way 

 of Eastern Asia. It is unknown on the western hemisphere. 



In the British Islands it is widely distributed, being found on the coasts and 

 on inland lakes and marshes, which it specially affects. It forms large colonies, 

 often called " Gulleries." The largest and most important in England are at 

 Scoulton Mere, in Norfolk; Cockerham Moss, in Lancashire, and Walney Island, 



