28 ANNALS OF SCOTTISH NATURAL HISTORY 



this way a whole brood is destroyed in a few minutes. We found 

 them waiting on the Greater Black-backed Gull, mobbing him 

 directly he had seized his prey, and compelling him to drop it, 

 in much the same way as a Skua. Often unable to swallow 

 their victims, they would leave them floating on the water. In 

 spite of these facts, their eggs are not smashed, nor is any 

 effort made to reduce their numbers. Once having found a 

 nest, they do not forget its whereabouts, and if driven off once 

 invariably return. Often they are to be seen catching flies in 

 the long grass in company with the Black-headed species. The 

 stomachs of specimens examined contained large quantities of 

 slugs and worms rolled together in a ball by tenacious mucus. 

 In the act of courting they assume curious positions, pouting 

 out their chests after the manner of a Pouter Pigeon. One I 

 saw wheeling and tumbling in the air almost like a Pewit. 

 Before the young are fledged, it would appear that they leave 

 the islands on which they were hatched and congregate on 

 some islet, possibly to evade the depredations of the Herring 

 Gulls. Thus one small island appeared almost grey from the 

 number of young birds we found on it, though there were no 

 signs of a single nest. On other lochs we noted the same thing. 



HERRING GULL, Larus argentatits, Linn. It is curious to note the 

 extent to which the different members of this genus prey 

 upon each other. Thus whenever a Herring Gull puts in 

 an appearance it is instantly mobbed by all the Common 

 Gulls. Large numbers nest undisturbed on an island in a solitary 

 loch amid the hills. Here each species have their own 

 particular boundaries : the Herring are confined to the most 

 exposed end ; in the middle a large colony of Greater Black- 

 backs, of which more anon ; finally an equally large one of the 

 Lesser Black-back. On two occasions we swam out to this 

 island and noted that the young of the two smaller species 

 were few in number, owing no doubt to the unwelcome 

 attentions of their larger neighbour. 



GREAT BLACK-BACKED GULL, Larus marinus, Linn. On the 

 island above mentioned there exists a colony of this species, 

 which for size must have rivalled that mentioned by Mr. 

 Harvie-Brown in his Fauna of the Outer Hebrides. Here I 

 counted no less than sixty-two old birds on one island. Here 

 too we killed no less than thirty-four young in all stages, and 

 took away four eggs. Many of the young when captured 

 ejected large slabs of fish, one in particular weighing at least 

 a pound. All the nests were huddled together in one small 

 area a hundred yards or so square. One young one whose 

 primaries were just sprouting survived an immersion of some 

 five minutes on his swim back to land. I found that he soon 



