GLAUCOUS GULL 441 



DESCRIPTIVE CHARACTERS. 



PLUMAGE. Adult male nuptial. Head, neck, breast, 

 abdomen, and tail, white ; back and wings, pale ' pearl ' 

 grey ; scapulars, secondaries, and outermost webs of the 

 primaries, tipped with white. 



Adult female nuptial. Similar in plumage to the male. 



Adult winter, male and female. Differs from the nuptial 

 plumage in that the head and neck are streaked with pale 

 greyish -brown. 



Immature, male and female. The plumage is light buff- 

 colour, profusely streaked and mottled with light ashy- 

 brown ; outer primaries, light nut-brown on the outer webs, 

 paler on the inner webs. With each moult the bird 

 becomes lighter, until, for a short time before maturity it 

 is entirely pure white. At this phase of plumage, in which 

 the ' pearl ' coloured feathers of the fully adult bird have 

 not yet appeared, the Glaucous Gull was described as 

 L. hutchinsi of Kichardson ; Mr. Saunders disposes of the 

 idea of a separate species, having watched the successive 

 plumage changes in captivity. 



BEAK. Yellow, orange at the angle. 



FEET. Bright pink. 



IRIDES. Yellow ; margin of eyelids, vermilion-red. 



AVERAGE MEASUREMENTS. 



Female smaller. 



Allied Species and Representative Forms. L. barro- 

 vianus of Kidgeway, is a Glaucous Gull of Alaska, but 

 Mr. Saunders can find nothing exceptional in specimens 

 from the North Pacific, and the Arctic regions of America, 

 including Greenland. But L. glaucescens, which inhabits 

 the Pacific north of lat. 40 N. is smaller, and its primaries 

 are chequered with pale grey. A large and rare represen- 

 tative found in Alaska and Vancouver Island, has been 

 named!/, nelsoni (Henshaw), while L. kumlieni, a smaller 

 bird, " with rather more definition in its wing-pattern," 



