BIRDS. 229 



Sub-family LARIN^E. 



Gulls may almost be termed the staple commodity in birds 

 in Orkney, and notwithstanding their constant persecution at 

 the nesting season, still fairly hold their own, if, indeed, some 

 species may not be increasing, as the Common and Black-headed 

 Gulls. 



Gulls have certain places on which they sit, and these may 

 be known by their green appearance, even amongst heather. 

 The reason of this seems to be that the gulls cast up the husks 

 of corn, on which they have been feeding, on these spots, and 

 this acts as a sort of manure to the ground. Mr. Moodie-Heddle 

 informed us that in Hoy there are nearly 120 acres thus used, 

 and that the castings represent many quarters of corn. 



Gulls swallow large quantities of mussels, which their 

 gizzards break up easily, the remains of the shells being found 

 in their castings ; they also swallow " buckies," 1 but these shells 

 are cast up whole. 



Enormous flocks of gulls are to be seen here and there 

 throughout the islands, even during the breeding season. Such 

 a flock we saw on Papa Westray, the birds composing it at first 

 sight seeming to be nearly all adults ; a closer inspection, how- 

 ever, showed them to be all, or nearly all, immature ; many of 

 them being in most interesting stages of plumage. 



Pagophila eburnea (Phipps). Ivory Gull, 



In addition to the specimens mentioned by Messrs. Baikie and 

 Heddle, our friend Mr. Eeid informs us that one was shot by 

 Mr. Eanken, Kirkwall, in 1849. 



Eegarding the one killed by Strang in the Bay of Firth, 

 the late Eobert Heddle has this note: "Eun off with by 

 James Sinclair," probably the birdstuffer living at Kirkwall at 

 that time. 



Mr. Moodie-Heddle informs us that an Ivory Gull was kept 

 alive at Melsetter, but gives no date. This may be the one 

 mentioned by Gray in his Birds of the West of Scotland, p. 481. 

 1 Buckies : Anglicb, Periwinkle. 



