154 THE GULLS 



as to the duration of the incubation period. When the young are 

 hatched they skulk about among the thick growth of water-plants like 

 the young blackheaded-gulls. 



W. Meves, in his account of the Ladoga colonies contributed to 

 Dresser's Birds of Europe, states that the noisy flocks which surround 

 the visitor to a breeding colony from time to time all leave as if by 

 some common impulse, but in a short time return and again renew 

 their expostulations. He also observed young of the previous year, 

 easily distinguished by the black band on the tail and the light head, 

 but they did not appear to be breeding. 



A great part of the food of this species consists of insects captured 

 on the wing. It also takes small fish, and at Lake Ladoga Meves 

 found that these constituted its chief food. They are picked up from 

 the surface of the water, and the gulls do not drop into it in the way 

 that the terns do, so that it is rare, according to Naumann, to see 

 more than the bill, head, and neck immersed in the water. The same 

 writer includes larva? of dragon-flies, water-beetles, and molluscs in its 

 dietary. The huge swarms of gnats and midges, which are hatched off 

 in millions from the waters of these shallow lakes, also provide a great 

 store of food, especially Chironomus riparius, according to Christoleit. 

 Towards evening great columns of these insects appear, dancing 

 in the air, and the gulls dash through and through them with 

 rapid flight, seldom rising more than twenty feet above the water, 

 which is about the height to which the flies ascend. About the 

 middle of July the young are fully fledged and are strong on the 

 wing. Soon afterwards they begin to leave their breeding-haunts, 

 and by the beginning of August all have disappeared for their 

 winter quarters. 



