THE IVORY GULL 347 



wing, ever on the look-out to seize any refuse 

 which may be thrown overboard, and apparently 

 never moving its outstretched wings, sailing along 

 in the wake of some Channel steamer which plies 

 between England and Ireland, to again return with 

 the next ship. 



It measures some fifteen inches, rather more 

 than less, and the summer plumage varies some- 

 what from that worn during the winter. At the 

 former season the head, neck, tail, and under parts 

 are white ; the bill greenish-yellow ; the feet nearly 

 black ; the mantle dark gray. 



In winter the nape and hinder part of the neck 

 are slate-gray. At both seasons the primary 

 feathers are tipped with black. 



The ivory gull may be described as a rare winter 

 visitor. Saunders states that but some thirty speci- 

 mens have been procured in the British Islands, 

 half of which appear to have been adults. Hailing 

 from the Arctic regions, the visitations of this bird 

 have been more frequent in the Northern portion 

 of Britain than elsewhere. Its plumage is entirely 

 white, the legs black. A peculiarity noticeable 

 in this gull is the web which connects the hind-toe 

 and the leg. It measures eighteen inches in length. 



Of the Stercorariinse, or predatory gulls, we 

 have four British varieties, viz. : 



1. The great skua. 



2. The twist-tailed or pomatorhine skua. 



3. Richardson's skua. 



4. The long-tailed or Buffon's skua. 



