92 BULLETIN 107, UNITED STATES NATIONAL MUSEUM. 
tinct spots and blotches. The measurements of 41 eggs, in the United — 
States National Museum collection, average 63 by 44.2 millimeters; 
the eggs showing the four extremes measure 67 by 47, 58 by 43, and 
63 by 41.5 millimeters. 
Young.—Both sexes incubate, although the greater part of this 
work falls upon the females. Baird, Brewer, and Ridgway (1884) 
state that the period of incubation is 1 month. Audubon (1840) 
says it is probably from 25 to 28 days. Only one brood is raised in 
a season. When the young are 4 or 5 weeks old they are able to leave 
their burrows and follow their mothers to the sea. A large nesting 
colony such as that at Parroquet Island, near Bradore, Labrador, is 
a place of intense interest early in August, when the parents are 
busily engaged in filling the wants of the hungry young. The water 
all about the place is dotted with puffins; there are weird looking 
groups of the birds on the rocks and the air is filled with the birds 
returning with food and those going farther afield in quest of more. 
The returning birds all have capelin—often several—or other small 
fish hanging from their bills by the heads, and in the swift flight of 
the birds the fish trail out parallel to the bill. The young birds wait 
at the mouth of the burrow for the feast and are always clamorous 
for more. Fish appears to be the chief of their diet, although shrimps 
and other crustacea and mollusca may be added. 
Plumages.—[ Author’s note: The young puffin is hatched in a coat 
of long, soft, thick down which covers the whole body; the central 
belly portion is white, sometimes tinged with yellowish or light gray; 
the remainder of the down, covering the upper parts, the throat and 
the crissum, is light “seal brown” with “drab” shadings; in some 
specimens the upper parts are “Prout’s brown” or “ Vandyke 
brown.” .The plumage appears first on the wings and then on the 
back and the last of the natal down disappears on the neck, rump, 
and flanks. This first winter plumage is somewhat like the winter 
plumage of the adult, glossy brownish black above and pure white 
below; but the loral and orbital regions are more extensively dusky 
than fe the adult, and the bill is very small, weak, undeveloped and 
pointed. This plumage is worn all winter and apparently through 
the first spring, until the young bird becomes indistinguishable from 
the adult after the first postnuptial molt, a gradual development of 
the bill taking place during the spring and summer. The adult has 
only a limited prenuptial molt in the spring and a complete post- 
nuptial molt in the late summer and fall. In the adult winter plum- 
age the face, or the whole lower portion of the head above the black 
collar, is much darker gray than in the spring; whether the light 
gray, almost whitish, face of the nuptial plumage is produced by 
molting or only by fading I can not say. The most conspicuous 
seasonal change in the pufiin is in the bill.] 
