LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 155 



daytime. But in tlie early liours of tlie morning tlie rocks of the bluff seemed 

 alive with them ; tliey all disappeared on the approach of dawn. This species 

 has three distinct notes, the one of displeasure being very harsh. According 

 to Blr. Brewster's book, it seems only one set of eggs of this species has been 

 taken and that was on the island of Raza in 1875, and was taken by Doctor 

 Streets. The island of Raza is over 300 miles north of San Jose Island. 



His letter is dated March 10, a few days after returning from the 

 islands. 



Eggs. — -The eggs referred to above, now in the Thayer Museum, 

 form a beautiful series and show interesting variations. They are 

 '• elliptical ovate '' in shape, smooth, and somewhat gloss3\ In a 

 general way they closely resemble the eggs of Xantus's murrelet. 

 The ground color varies from '' Sayal brown '• or *' snufl' brown " 

 to '* light pinkish brown,^' " ivory yellow,'- or various pale shades 

 of olive or buff which are almost white. The markings are very 

 variable also; some eggs are finely and evenly sprinkled with small 

 spots or dots oAer the whole surface, and in others these markings 

 are gathered in a ring about the larger end; some are heavily spotted 

 or blotched irregularh' or in a wreath about the larger end; the 

 markings are in various shades of brown, mostly the darker shades, 

 with underlying spots or blotches of various shades of lilac or drab. 

 The measurements of 31 eggs, in various collections, average 52.3 by 

 34.9 millimeters; the eggs showing the four extremes measure 55 

 by 34.5, 53 by 37, 48.5 by 35, and 54.5 by 32.5 millimeters. 



Plumages. — The newly hatched downy young has never been de- 

 scribed and, so far as I can learn, no such specimen exists in any 

 collection. Mr. Brewster (1902«) has carefully described the de- 

 velopment of the plumage of the young bird, as follows : 



Two of Mr. Frazar's specimens, both taken on the same date (March 1), 

 i:re young, about one-half grown and still clothed, for the most part, in down. 

 This, over the upper parts, is seal brown, slightly redder as well as paler than 

 in adult birds and with fine transverse markings of whitish besprinkling 

 the back and rump, but not the crown nor the wings. The throat is grayish, 

 the abdomen white. On the jugulum and breast the down has been replaced 

 by true feathers, those of the second stage of plumage and everywhere silky 

 white save on the sides of the breast, where they are flecked with minute 

 spots of blackish. The sides of the body with the under as well as the upper 

 surfaces of the wings are covered with down of nearly the same shade of 

 brown as that of the crown and back, but there are also a few budding wing 

 coverts, as well as quills, the expanding tips of which are decidedly darker 

 in color. 



Other specimens in my series illustrate practically every stage through 

 which the young pass in arriving at maturity. They show that the natal 

 down is shed first on the breast, next on the throat and abdomen, next on 

 the wings, next on the back, next on the chin, next on the center of the crown, 

 next on the forehead, last of all on the occiput and sides of the crown. With 

 the disappearance of the last shreds of down the bird completes what I 

 suppose must be called its first winter plumage, although this in specimens 



