IVORY GULL. 229 



forked tail is much more pronounced than that of the Little 

 Gull. Many of its visits have been when terns were on the 

 move, and it has been seen associating with them ; indeed, 

 Mr. Caton Haigh was reminded of the note of the Arctic Tern 

 when he heard a young Sabine call. 



In its nuptial dress, which is occasionally seen in England 

 — ten or a dozen have been noted in this plumage in Yorkshire 

 alone — the head and neck are slate, with a black line where the 

 hood meets the general white plumage. The back and wings 

 are dark pearl-grey, the outer primaries are black tipped and 

 inwardly margined with white, and the inner primaries and 

 secondaries are mostly white. The yellow-tipped bill is black, 

 the legs are brownish black, and the irides, at any rate in some 

 examples, red. In winter the head is only marked with grey 

 streaks and suffusion. Young birds have the back, wings, and 

 a patch on the side of the breast ashy grey with brown bars ; 

 the nape is dusky and the forked tail broadly bordered with 

 dark brown. Length, 13 ins. Wing, 1075 i^s. Tarsus, 1*3 ins. 



lYOry Gull. Pagophila ebiirnea (Phipps). 



The Ivory Gull (Plate 103) is another circumpolar bird which 

 is almost an Arctic resident, but wanders south occasionally, 

 and has reached most parts of our islands, though it is best 

 knoAvn in the Orkneys and Shetlands. Though a winter visitor 

 it has remained so late as June ; unlike the last species, as 

 many mature as immature birds are met with. 



In its adult dress, whether in summer or winter, this gull is 

 white ; the white mantle distinguishing it from all others. 

 The white of immature birds is spotted with dark grey or black 

 to a variable degree, possibly due to age ; in some the upper 

 parts only are sparsely spotted, but in others the under parts are 

 similarly marked. The primaries have black tips and the tail 

 a subterminal brown-black band. Col. Fielden thought both 



