LIFE HISTOKIES OF NORTH AMEEICAN WILD FOWL 147 



The color is a very pule " cartridge buff," or a pinkish or buff y 

 v.hite. Mr. Millais (1913) describes the eggs in the Massey collec- 

 tion as *' rather pointed in shape, creamy in color." The measure- 

 ments of 33 eggs, in various collections, average 61.6 by 43 milli- 

 meters; the eggs showing the four extremes measure 67.5 by 43, 

 59 by 45, 58 by 41, and 59 by 40.5 millimeters. 



Plumages. — Strangely enough there does not seem to be a single 

 specimen of the downy young surf scoter in any American or Eu- 

 roj3ean collection, except two half-grown young in the Museum of 

 Comparative Zoology, in Cambridge, Massachusetts, collected by 

 Francis Harper on Athabasca Lake, on July 28, 1920. Although as 

 large as teal, these birds are still wholly downy, with no trace of 

 appearing plumage. The smaller, a female, has the crown, down 

 to and including the eyes, a deep glossy " clove brown " in color ; 

 the color of the black varies from " olive brown " anteriorly to 

 '' clove brown " on the rump ; the sides of the head and throat are 

 grayisli white, mottled with " clove brown "; the entire neck is pale 

 " clove brown " ; the colors of the upper parts shade off' gradually 

 into paler sides and a whitish belly. In younger birds these colors 

 would probably be darker, brighter, and more contrasted, as they 

 are in other species. 



In the Juvenal plumage the sexes are alike. The crown is very 

 dark, blackish brown, conspicuously darker that the rest of the 

 plumage ; the upper parts are dark brown and the lower parts lighter 

 brown and mottled; there is a whitish loral space and a smaller 

 whitish auricular space; the tail feathers are square tipped; and 

 there is no trace of the white nuchal patch. During the first win- 

 ter, beginning sometimes as early as October but often not until Feb- 

 ruary, the sexes differentiate by the growth of new black feathers in 

 the male and brown feathers in the female; this growth begins on 

 the head, scapulars, and flanks, whence it spreads, before spring, 

 until it includes all the fore part of the body and much of the back, 

 leaving only the juvenal wings, part of the back, and the central 

 under jjarts, which fade out almost to white ; tlie tail is molted dur- 

 ing the winter and the new feathers are pointed at the tip. The 

 white nucluil patch is acquired by the young male before spring, but 

 not the frontal patch; the bill assumes its brilliant coloring and in- 

 creases in size, but it does not reach its full perfection for at least 

 another year. 



A complete postnuptial molt takes place in August, Sei)tember, or 

 even later in young birds, which produces a plumage which is prac- 

 tically adult. The male acquires tlie white frontal |)atch and the 

 female the white nuchal patch at this molt and the bills become more 

 mature, but full perfection is probably not attained for another year. 



