V0l i9™ n ] Dwight, The White-winged Gulls. 35 



differ from glaucus, as a rule, although the primaries more fre- 

 quently have white or brownish shafts untinged with the yellow 

 so prominent in glaucus. Some birds, too, are in the mottling 

 perhaps more black and white rather than brownish. Second 

 year birds more often have adult mantles than do second year 

 glaucus, but the creamy or pinkish drab, or white primaries and 

 brown mottled feathers in wings or tail betray their age. The 

 white phase is also illustrated by two specimens, one in the collec- 

 tion of Mr. Everett Smith which is white except for a few pearl- 

 gray feathers on the back, very pale drab primaries, and a few 

 obscure mottlings on otherwise white feathers, and one in the 

 American Museum which is pure white except for a small area 

 of gray on the back. These are doubtless birds that have passed 

 through the first postnuptial moult like ' hutchinsii,' and the 

 partly yellow bills support this assumption. They are probably 

 the ' candidus' and ' glacialis' of early writers. 



It should also be noted that in adults the mantle is rather darker 

 than that of glaucus, although the color of each species varies 

 somewhat in shade. In both of these gulls the gray is subject to 

 considerable fading, and the transition from gray to white a couple 

 of inches or so from the tips of the primaries is never abrupt. 



Larus glaucescens. Glaucous-winged Gull. 



While this medium-sized gull is not properly white-winged, 

 I introduce it here for purposes of comparison. Its range is 

 along the western coast of North America from the United States 

 northward. In size it is a little larger than leucopterus with a 

 much larger bill; in all plumages it differs radically from glaucus 

 and leucopterus. 



The juvenal plumage is deep plumbeous gray with broad dark 

 barring or mottling and obscure whitish edgings. The tail is nearly 

 solidly gray sprinkled basally with white, and the flight-feathers, 

 including the quills, are also dark gray. The legs and feet are 

 flesh-colored and the bill brownish black. Birds in this plumage 

 are never so pale (especially the primaries) as the darkest leucop- 

 terus, nor are they ever so dark as the palest of the black-pri- 



