54 BULLETIN 180, UNITED STATES NATIONAL MUSEUM 



the lores, hind neck, back and rump ; the under parts, including the 

 cheeks up to the eyes, are pure white ; there is a white spot above and 

 in front of the eye and an indistinct whitish streak on each scapular 

 region; the front of the wing is margined with white. The juvenal 

 plumage comes in first on the flanks and scapulars; the former are, 

 at first, " olive brown " Avith white tips and the latter are " warm 

 sepia.*' 



In the juvenal plumage in the fall the young male resembles the 

 adult female, but can bq recognized by the looser texture of the 

 plumage, the worn tail, the gray instead of brown flanks, and by 

 having less white on the breast. J. G. Millais (1913) says: 



Toward the end of November the young male begins to assume the adult 

 dress rapidly ; the tail and tail coverts are replaced by adult feathers ; a tinge 

 of burnt sienna appears on the long flank feathers ; tlie wing coverts, the scapu- 

 lars, mantle, and the whole of the adult feathers on head and neck come in, 

 so that by the end of January a young male in my possession is almost like an 

 adult, except for the smaller black and white bars on the sides of the chest, 

 a brown rump and bill, mottled and immature under parts, and immatiu'e wings. 



The change then proceeds very slowly. From specimens in Mr. Schioler's 

 collection it is clear that the male harlequin follows the same course of 

 plumage as the long-tailed duck and the goldeneye. A greater or lesser part of 

 the immature under parts are shed between the months of March and June, and 

 the last signs of immaturity in the shape of the wings are not shed until late 

 July or August, when the young male goes into an eclipse similar to the adult 

 male. By September the new wings are obtained and the portions that were 

 assumed as eclipse are being shed, so that it is not until November — that is, at 

 14 months — that the young male stands in full dress. It will breed in the fol- 

 lowing spring. 



This does not agree with what specimens I have seen, which indi- 

 cate that the young male makes but little progress toward maturity 

 during his first year. Among the large flocks of immature males 

 which we saw in the Aleutians in June very few birds showed any- 

 thing approaching the adult plumage, and most of them could hardly 

 be distinguished from females, except at very short range. Most of 

 the specimens seen and collected were in worn immature plumage, 

 dull brown above, with lighter edgings, wholly mottled below, and 

 with varying amounts of the slaty feathers and the white markings 

 of the adult on the head. Perhaps these were especially backward 

 birds, and others, which we took to be adults, were normal or ad- 

 vanced young birds; but the latter were certainly in a very small 

 minority. 



The young female requires about the same time to reach maturity — 

 about 16 months. Mr. Millais (1913) says: 



There seems to be less difference between the young and adult female harle- 

 quin than almost any of the diving ducks. Yet the immature female, prior to 

 February, when the new tail is assumed, can always be recognized by the worn 



