178 LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS 



Plumages. When first hatched the young murre is covered with 

 short down which varies from "bone brown" to "hair brown" above, 

 almost black on the head and neck, except that the throat is mottled 

 with white; the under parts are white; the head and neck are sparsely 

 covered with long, hairlike filaments, grayish white or buffy white 

 in color, giving the bird a coarse, hairy appearance. The Juvenal 

 plumage is acquired when the young bird is about half grown and is 

 not very different, except in texture, from the first winter plumage, 

 dark "seal brown" above, including the sides of the head and neck, 

 the throat mottled with dusky and whitish and the under parts white ; 

 there are no white tips on the secondaries in this. plumage and the 

 bill is very small. This first plumage is replaced, by the end of Sep- 

 tember, by the first winter plumage, which is similar to the adult 

 winter plumage. Young birds may be recognized, however, by their 

 smaller and lighter colored bills, by their mottled throats, and by 

 having less white on the sides of the head and neck. A partial molt 

 takes place in the spring, at which a plumage similar to the adult 

 nuptial plumage is assumed; but young birds are still recognizable 

 by their bills until after the postnuptial molt, when the adult plumage 

 is assumed. 



Adults have a complete postnuptial molt beginning sometimes in 

 August but often not until September; I have seen birds beginning 

 to molt as early as August 2 and others which had not started to molt 

 on September 11; I have also seen birds in full spring plumage in 

 December. Adults in winter can be recognized by having larger 

 and blacker bills, white throats, and more white on the sides of the 

 head and neck than in young birds, although the latter character is 

 not very well marked. The adult winter plumage is worn for a short 

 time only, as the prenuptial molt sometimes begins as early as No- 

 vember and is often completed in December. In studying large series 

 of California murres I have been puzzled to decide whether certain 

 fall specimens were molting into or out of the winter plumage, and I 

 am led to infer that the birds are in nearly continual molt throughout 

 the fall, and that many individuals never acquire the full winter 

 plumage, as the two molts may overlap. Probably most of the birds 

 in winter plumages in collections are young birds, as the prenuptial 

 molt in young birds does not occur until spring. 



Before leaving the subject of plumages we might consider briefly 

 the status of the ringed murre (Uria ringvia), which now seems to 

 be regarded as a plumage phase of the common species. The evi- 

 dence is puzzling and far from conclusive, though most of it seems 

 to indicate that the ringed murre, with its conspicuous white spec- 

 tacles, is a distinct species. Macgillivray ( 1852 ) treats it as a doubt- 

 ful species under the name Uria lacrymans, but says that, in search- 

 ing his collections, he finds "only one specimen, which, however, is 



