242 THE BIRDS OF NORTHAMPTONSHIRE 



this Gull nesting in any numbers together, as it is 

 said to do in certain localities on the coast, and on 

 the islands of certain freshwater lakes : the few nests 

 that I have seen were built upon some of the 

 islets of the Scilly group, generally on their grassy 

 summits ; three nests were the greatest number that 

 we met with upon any one of these isolated rocks, 

 and only two of these had been occupied in the 

 breeding-season, which was just over at the time 

 of our visit. These nests were evidently the accu- 

 mulation of several years, and were composed of 

 piles of withered "marram" and other grasses, with 

 a few sticks and some fragments of rabbit-skin : 

 although the young birds could ily and take very good 

 care of themselves, their parents were very savage 

 and swooped at us, barking angrily, as we clambered 

 about the rocks ; in fact they appeared to be perfectly 

 fearless of man, although I have generally found 

 them very wide awake during the winter months. 

 The Great Black-back fears no other bird, and, as 

 I am assured on good authority, holds even the 

 Great Skua, the terror of all other Gulls, at defiance. 

 I am not aware that this species is held in more 

 abhorrence on the Grouse-moors than the two 

 species last treated of, but its tastes are certainly 

 just as indiscriminate and its aggressive powers 

 much greater. In my experience this is a rare 

 bird in the Mediterranean ; I have occasionally seen 

 solitary adults upon the Guadalquivir nearly as high 

 up that river as Seville. 



