38 Dwight, The White-winged Gulls. [j" n k 



tail is a feature not seen in leucopterus. Besides this, the barring 

 and mottling is much coarser and darker. In one of the birds 

 there is a faintly indicated whitish subapical spot on the first 

 primary, but similar spots may be found in other species of gulls 

 and it seems to be a variable character of little importance. These 

 specimens are perhaps not 'in full juvenal plumage, for they are 

 probably partly in first winter dress, and two of them, just begin- 

 ning the prenuptial moult, have acquired a few gray nuptial feath- 

 ers of the mantle, but it must be remembered that the differences 

 between juvenal and first winter plumages of the gulls are inappreci- 

 able. It is probable that the brown shade is due to fading and 

 that earlier in the season these birds were grayer. They also bear 

 quite a close resemblance to L. californicus in similar dress, but 

 in this species the primaries are usually very much darker. In 

 thfe young bird figured, Plate I (Collection of J. D., Jr., No. 7711, 

 Tadousac, Que.) the wings, tail and part of the body plumage 

 are juvenal, while some of the body feathers are doubtless the 

 brown first winter with a sprinkling of the new first nuptial dress. 



First Winter Plumage. — From what has just been said it has 

 been made evident that this plumage differs in practically no 

 respect from the juvenal. The postjuvenal moult is variable 

 in the time of its occurrence, just as it is in all the gulls, and over- 

 laps the prenuptial so as to be in many cases confused with it. 



First Nuptial Plumage. — This plumage doubtless closely 

 resembles the juvenal or the first winter, but birds may be expected 

 to become whiter about the head and with a few gray feathers 

 on the back. 



Second Winter Plumage. — Like leucopterus, this species attains 

 a considerable amount of adult plumage at this moult. The 

 gray mantle, clouded white head and body and white tail indicate 

 a close approximation to the adult plumage, but the primaries 

 and other feathers of the wings are usually drab and not very 

 much paler than in first winter birds. Dark gray or mottled 

 feathers may also be found on the wings or tail or on the body 

 posteriorly. The bills are yellow but often clouded and with 

 the red spot lacking. The variation is considerable, just as in 

 glaucus or leucopterus or glaucescens, but the darkness of flight- 

 feathers or tail or of both combined is a character useful in sepa- 



