70 BUJ^LETIN 130, UNITED STATES NATIONAL MUSEUM 



The measurements of 75 eggs, in various collections, average 



61.4 by 42 millimeters; the eggs showing the four extremes measure 



70.5 by 45.5; 66.9 by 47.1, 55.5 by 40.5, and 59.2 by 37 millimeters. 

 Plumages. — The downy young Steller eider is easily recognizable, 



as it is quite different from the young of other species. The bill, 

 even in the smallest specimens, shows the characteristic shape pecu- 

 liar to the species, tapering evenly from forehead to tip, slightly 

 compressed in the middle, with an overhanging upper mandible 

 near the base ana near tiie tip. The color is decidedly dark; the 

 upper parts, including the crown, hind neck, back, and rump are 

 very dark, glossy " bone brown " or " clove brown " ; slightly lighter 

 shades of the same colors extend downwards on the sides of the 

 head to the chin and throat, on the sides of the body and across the 

 chest ; there is a " buffy brown " spot above the eye, a whitish spot 

 below it and a stripe of " buffy brown " behind it ; the throat and 

 chin are " light vinaceous cinnamon " or " pinkish buff " in the 

 youngest birds, grayer in older birds, the colors merging gradually 

 into the darker colors above; the breast and belly are dull, silvery, 

 grayish brown, invaded on the sides w^ith darker browns. The bill 

 and feet are black in dry skins. 



In the Juvenal plumage, during the first fall young males and 

 females are very much alike and somewhat resemble the adult 

 female except that they are lighter colored, redder, and more mottled 

 below; in the young male the breast and flanks are heavily barred 

 with rich reddish brown or " chestnut " : while in the young female 

 the under parts are barred with paler browns ; in the young male the 

 wing is much like that of the adult female, with the curved tertials ; 

 but in the young female there is less blue in the speculum and the 

 tertials are straighter, less curved. In both sexes the feathers of the 

 back and scapulars have brownish buff edgings; and the under 

 parts are wholly mottled or barred, instead of being uniform dark 

 brown as in the adult female. 



During the first winter and spring the sexes begin to differentiate 

 more. The young male becomes lighter colored; the dusky throat 

 patch and the black n«ck ring begin to show; the breast begins to 

 assume a tawny shade; and in some forward birds some of the 

 white-edged scapulars and long curved tertials appear before sum- 

 mer. But, on the whole, there is not much change until the sum- 

 mer molt occure in July and August. This produces what might 

 be called a first eclipse plumage, relatively similar to that of the 

 common eider. The plumage is completely changed during this 

 molt, after which old and 3'oung birds are practically indistinguish- 

 able. 



