306 CHARADRIIFORMES 



Tarrock, is much variegated with dark grey or- black, and has a 

 blackish tip to the tail, as is the case iii most fresh-water Gulls. 

 Many fine colonies inhabit the loftier cliffs of Great Britain, the 

 nests of sea-weed and grass being closely crowded together, and 

 the eggs exhibiting softer colours_than is usual in the Sub-family. 

 The darker B. hrevirostris of Bering Sea has red feet. 



Pagophila ehurnea, the Ivory Gull, seems truly circumpolar, 

 while it accidentally visits Britain, Northern Europe, and New 

 Brunswick. It is pure white, with black feet, the young shew- 

 ing grey and black variations. It will eat whale- or seal-offal. 



Zeucophaeus scoresMi, of South Patagonia, the Falkland 

 Islands, and the neighbouring Antarctic seas, has a crimson bill, 

 coarse red feet, with somewhat excised webs, a dark hood in 

 immature examples, and a white tail. Gabimius pacijicus of 

 Australia and Tasmania is somewhat like Larus marinus, but 

 has a very short stout bill and a black-banded tail. 



In the genus Larus, as throughout this Family, the arrange- 

 ment followed is that of Mr. Howard Saunders,^ much of whose 

 admirable work is here incorporated. His first section com- 

 prises species with a white tail but no hood, the young having 

 the head striated. Of these, L. glaucus, the Burgomaster or 

 Glaucous Gull, and L. leucopterus, the Iceland Gull, are the only 

 members of the group with nearly white primaries, the former 

 being larger, with proportionately shorter wings. In summer 

 the former is circumpolar, and the latter occurs from Jan Mayen to 

 Greenland and perhaps the west side of Baffin Bay ; in winter 

 both visit Britain, but the latter only reaches the Gulf of Gas- 

 cony, and Boston in America, whereas its ally extends to the Medi- 

 terranean, the Caspian, Japan, California, and the Bermudas. At 

 this season the head shows brown markings ; while the young are 

 entirely mottled, though they apparently become creamy white 

 just before assuming the grey mantle. Z. glcmcescens of the 

 North Pacific, Z. nelsoni of North- West America, and Z. kumlieni 

 of Cumberland Sound have the quills chequered with grey, and 

 connect the above with the following or blacker-quilled group. 



Z. argenicUus, our Herring Gull, has a blue-grey mantle ; the 

 black primaries shew white tips and "mirrors" or round white marks, 

 as well as a grey wedge on the inner web ; the feet are flesh-coloured, 



' Gal. Birds Brit. Mas. xxv. 1896 ; J. Linn. Soc. xiv. pp. 390-406 ; f.Z.S. 

 1876, pp. 638-672, 1878, pp. 155-212. 



