c8 DwiGHT, Moults and Plujuages of Gulls and Terns. \^^n 



also gray, the black nuchal patch usually being obliterated by new 

 feathers. The claim of a color-change without moult in Lams 

 ridibiDidus is not substantiated by a series of specimens taken 

 throughout the year. In first winter plumage there is a brownish 

 crown patch and occipital band concealed by white or gray feather 

 tips, much as in L. Philadelphia, and as these wear off the brown 

 comes more into view, but at the same time new darker brown 

 feathers grow. A specimen in the midst of a second (or later) 

 prenuptial moult (Amer. Museum No. 54632, 9 , March 6, 

 England) shows new growing feathers not only on the head but 

 elsewhere ; the forehead anteriorly still retains the worn white 

 plumage of the winter dress. Another bird (Amer. Museum No. 

 26977, 9, March 25, France) has acquired the full brown hood 

 of new feathers, some of them still pushing out from their sheaths. 

 If such feathers were recolored how is their perfect structure to 

 be explained ? 



We come now to a third type of moult which is peculiar to all 

 of the larger Gulls, and I have chosen as a representative species 



Larus argentatus Briinn. Herring Gull. 



1. Natal Doivn.- — Grayish above with obscure mottling on 

 the back and black spots on the head and throat, paler below. 



2. Jirt'cnal Plumage acquired by a complete postnatal moult. 

 Above grayish brown with whitish and buffy edgings ; below 

 plumbeous with inconspicuous whitish mottling, the head and 

 neck paler and tending to streaking. The primaries are uni- 

 formly brownish black. The rectrices are similar but basally, and 

 the outer one slightly, mottled with grayish white. The bill is 

 plumbeous and the feet flesh-colored. 



3. First Winter Flu mage acquired by a limited postjuvenal 

 moult which is apparently either suppressed in some individuals 

 or postponed till the prenuptial period. The worn and faded 

 Juvenal dress is replaced on the back, head, and sides of breast 

 by a similar plumage, which, however, is somewhat grayer and 

 more mottled. November specimens are most apt to show this 

 growth, which is very gradual and easily overlooked. 



