JACKDAWS AS EGG-STEALERS. 



257 



The defenceless character of all the Terns 

 makes their eggs and young easy prey for any 

 winged depredator that happens to come along. 

 Jackdaws fly over from the mainland to harass 

 them, and sometimes even levy toll upon the 

 nests of the Lesser Black Backs and Herring 

 Gulls, whose eggs they finish devouring on the top 



LESSER BLACK-BACKED GULLS. 



of St. Cuthbert's Tower. This necessitates a 

 periodical inspection of the little bit of flat roof 

 by the watchers, who have to depend upon it for 

 the collection of their fresh water, and therefore 

 cannot afford to have it fouled by offensive matter. 

 Often our attention would be called across the 

 water by a great clamour and commotion, and, turn- 

 ing our field-glasses in the direction from whence 

 it came, we could see a vast congregation of Terns 

 hovering close over some particular part of then- 

 is 



