112 NORTH AMERICAN FAUNA 61, FISH AND WILDLIFE SERVICE 



Field observations on numerous immature birds in Alaska were 

 confusing, and we were unable to correlate some plumage patterns 

 with age. 



The downy-young plumages are well known and are well de- 

 scribed by Bent. However, the color of beak, eyes, and other 

 soft parts is not so well known. A young bird in the dark-down 

 stage on Ananiuliak Island had a slate-colored upper mandible, 

 the cere was of a similar color, but it was of a little lighter 

 shade. The tip of the lower mandible was similar to the upper 

 in color, but posteriorly the margin of the gape was flesh color, 

 becoming paler posteriorly and shading into a near-yellow at the 

 corner of the mouth. The lores were dull bluish. The iris was 

 dusky brown, and the pupil was blue. The eyelids were pale 

 plumbeous. The feet were a yellowish-clay color, and the claws 

 were slaty. 



The first-year plumage is dark ; as Bent says, "uniformly 

 dark 'bone-brown' to 'clove brown' above and below; the flight 

 feathers are nearly black, but there is usually a slight sprinkling 

 of grayish white in the tail." In the first year, both the bill and 

 cere are of a blackish-slate color. The iris is brown, and the 

 pupil is black. At this stage, the eyelids are still plumbeous. 



The plumages preceding the final adult stage are hard to 

 define. There appears to be much variation, probably over a 2- 

 year period. Assuming a 2-year period for the post ju venal 

 phases, the plumage varies in the degree of white mottling. 

 The essential feature is a pattern that includes patches of dull- 

 white mottling on scapulars and back (which, in flight, show as 

 three distinct areas), and light-colored upper tail coverts and 

 considerable white in under parts. In one phase of this plumage, 

 which must be in the second year, the bill and cere are still 

 blackish and the eye is still a rich brown. The preocular area 

 is essentially white, the eyelid is plumbeous, and the gape is 

 dull yellowish. The feet are yellow. 



A later phase, which possibly may represent the third year, 

 still includes the dark bill, with a dull-yellowish hue appearing 

 on the lower mandible and the margin of the cere. The eye is 

 dull yellow also, and a yellowish tinge is encroaching upon the 

 preocular area. The eyelid is gray, and the gape is yellow. There 

 is much light speckling on the head, though the head is chiefly 

 brownish. The specimen on which this description is based did 

 not have the light mottling on upper parts falling into a pattern 

 of three light patches, as was seen on many birds; instead, it 

 was more scattered. 



