436 LAEID^E 



its formidable beak ; even weakly lambs may fall victims 

 (Saunders). Fish, dead or alive, are consumed in great 

 quantities, a Great Black-backed Gull being capable of 

 swallowing a mackerel two pounds in weight (Payne- 

 Gallwey, 'Fowler in Ireland'). At the same time this 

 species is a good scavenger, stranded and foul-smelling 

 carcases being speedily demolished. The numbers of dead 

 dogs, cats, pigs, &c., washed ashore from time to time at 

 the mouths of city rivers always attract party-gatherings. 

 I have seen two (which I surmise were the same couple 

 each time, one being a mottled first year's bird, the other 

 older, and showing the signs of mature plumage about 

 the back and wings) resort daily to a particular spot on 

 the beach, just as the receding tide began to lay bare the 

 drowned carcase of a large terrier dog moored to the spot 

 by a stone attached to the neck-rope. On my approacli 

 they walked sedately from their feast, returning when I 

 ambushed myself behind a sand-bank. They always moved 

 to and from the carcase with the same deliberate gait, 

 looking suspiciously on all sides before resuming their 

 repast. In less than a week the carcase was reduced to 

 hide and skeleton. 1 The animal had been drowned when 

 in good condition, and was fresh when I first discovered 

 the Gulls attacking it. 



Nest. In the breeding-season the Great Black-backed 

 Gull becomes more or less gregarious, though its colonies 

 are often composed of but very few pairs. It usually selects 

 the summit of a lonely stack which is tenanted by a single 

 pair, but, on larger islands, several eminences are thus 

 occupied ; and in the case of the Bills of Achill, lofty rocks 

 that stand seven miles from Achill Head, Mr. Ussher found, 

 in 1890, probably the largest British colony known, estimated 

 at some fifty pairs. He writes : " The young, and the nests 

 which they had in many cases quitted, lay around us among 

 bosses of gigantic thrift, not on the top of the rocky ridge, but 

 on the slope beneath it facing south" ('Birds of Ireland'). 

 In Scotland and in the Lake district, it breeds away from 

 the tide on the islets of mountain-lakes. The nest, like 

 that of many other Gulls, is composed of grasses, bits of 



1 I kept this carcase under close observation daily for the short time 

 that it was visible at ebb-tide, and with the exception of occasional 

 visits from a few Herring-Gulls, it was apparently entirely disposed of 

 by the two Black-backed Gulls. 



