VOl iio? I3tI ] Dwight, The White-winged Gulls. 31 



as fall specimens always reassume brown feathers while late winter 

 birds acquire much paler brown feathers usually mixed with white 

 or gray ones, thus approaching the plumage of the adult, it is but 

 logical to assume that some birds at least undergo a double moult 

 during the first winter of their lives. In juvenal plumage the back 

 and upper surface of the wings is dull white, the individual feath- 

 ers coarsely barred and mottled with a pale buffy brown or drab- 

 gray, giving a 'watered' effect, as if the color had run. The' head, 

 throat and neck are similar but paler, the brown in obscure streaks, 

 and the lower parts are darker gray with indistinct clouding. The 

 tail resembles the back but the mottlings are generally finer. There 

 is considerable variation in the color of the primaries and second- 

 aries of different specimens. They vary from pale ecru-drab, 

 which tinges the yellowish white shafts, to dull white with straw- 

 yellow shafts. There is usually a subapical dash or spot of brown, 

 most conspicuous on the inner and often lacking on the outer pri- 

 maries, especially if these be white. The first primary is usually 

 palest on the outer web, and nearly all of them become paler to- 

 ward their tips where occasionally an obscurely indicated white 

 area may be found. The legs, feet and eyelids are flesh colored, 

 becoming brownish ochre in the dried skin. The bill of very 

 young birds is also largely flesh colored, later becoming bluish 

 black at the tip beyond the nostril and drying in skins to a brown- 

 ish black with the base dull buff-yellow. The iris is brown and, 

 like the bill, remains of the same color for about a year. 



First Winter Plumage. — Acquired by a partial postjuvenal 

 moult. As explained earlier, this plumage does not appear to 

 differ from the juvenal which it only partially supplants, chiefly 

 on the back. The overlapping of the postjuvenal and prenuptial 

 moults obscures the question of whether all young birds pass 

 through one or two moults during their first winter, but the evi- 

 dence is in favor of two. Before the time of the prenuptial arrives 

 birds have faded out a good deal and are often quite white in 

 appearance with the brown mottling very obscure. The paler of 

 the drab primaries apparently fade to white in some cases. 



First Nuptial Plumage. — Like many other species of the larger 

 gulls glaucus does not breed the first year and most of them remain 

 in a brown plumage not materially different from the juvenal. 



