92 BULLETIiSr 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. 



Plvmiages. — [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 in 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 puffin is in the bill.] 



