254 



BAY, SEA OR DIVING DUCKS 



JUVENILE. In September the sexes are alike and somewhat like adult 

 female except the white face-patch does not extend across forehead, is less clearly 

 defined and is mottled with brown; head, neck and chest are paler brown. Dur- 

 ing October both sexes make steady progress towards maturity and the purplish- 

 black feathers begin to appear on head and neck of young male; the brown 



feathers of back begin to be replaced by grey- 

 ish, and vermiculated black-and-white feathers 

 appear in scapulars; in November the first black 

 feathers appear in the chest; by February the 

 head is almost adult. The plumage of both 

 sexes is practically adult by spring. Wing of 

 both sexes. As in adult female but coverts of 

 young male show some vermiculation (as in adult 

 male) on lesser and middle coverts and also on 

 tertials. 



FIG. 46. Above, bill of Greater 



Scaup. Below, bill of 



Lesser Scaup. 



SPECIMEN IDENTIFICATION 



MALE. WINTER PLUMAGE: General effect: 

 A medium-sized, grey-backed duck, with white 

 breast and sides, and black head, neck and fore- 

 quarters. Chief distinguishing features (a) hind 

 toe with lobe, (b) solidly black head glossed 

 with purplish; black neck, chest and foreback, 



(c) back, whitish, vermiculated with black, (d) white speculum, but no white on 



primaries, though three inner ones may be palish. 



Practically identical with male Greater Scaup Duck except gloss of head is 



predominantly purplish instead of 



greenish; is somewhat smaller; nail of 



bill is narrower, and bill less deep at 



base (fig. 46); respective bill measure- 



ments are: Greater Scaup, greatest 



width .85 to 1.05 inches, Lesser Scaup, 



.85 to .95 inch. The Greater Scaup 



has six and sometimes seven inner pri- 



maries marked with white, producing 



a long, white wing-stripe; the Lesser 



Scaup has no white on the primaries, 



though the three inner ones may be 



very pale, but seldom approaching the 



whiteness of those of the Greater 



Scaup (fig. 47). The sides of the 



Greater Scaup, in full plumage, are 



practically pure white, while the Lesser, 



on the average, shows much dusky 



vermiculation. The feathers of the 



crown and nape of the Lesser are longer Bd w{ 



and fuller giving the bird a "higher- ^^ ^ 



appearing" and more angular head. 



Similar also to the male Ring-necked Duck, but that species has black back and 



pearl-grey speculum. 



AUTUMN AND JUVENILE PLUMAGE: See "Descriptions." 



FJG 47 ._ Ab wi of Greater Scaup , 

 ' h 



flight-feather?. 



