LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 155 
daytime. But in the early hours of the morning the roeks of the bluff seemed 
alive with them; they all disappeared on the approach of dawn. This species 
has three distinct notes, the one of displeasure being very harsh. According 
to Mr. 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 glossy. In a 
general way they closely resemble the eggs of Xantus’s murrelet. 
The ground color varies from “Sayal brown”: or “snuff 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 over the whole surface, and in others these markings 
are gathered in a ring about the larger end; some are heavily spotted 
or blotched irregularly 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 34 eggs, in various collections, average 52.3 by 
34.9 millimeters; the eggs showing the four extremes measure 55 
by 34.5, 58 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 (1902a) 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), 
are 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 On the jugulum and breast the down has been replaced 
by true feathers, those of the second stage of plumage and everywhere silky 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 
