334 BAY, SEA OR DIVING DUCKS 



AUTUMN PLUMAGE: Same as winter plumage. 



ADULT FEMALE. Head and neck, dusky brown, with vague whitish patch 

 on back of head (lacking in yearlings), the whitish colour being produced by 

 presence of short, dark-brown feathers among the white; crown, to just below eye, 

 black; cheeks, with two obscure white patches, one over ear, and the other be- 

 tween eye and base of bill; bill, blackish, with black patch at base, surrounded by 

 pale grey; bill, less swollen than in male, and frontal feathers not extending as 

 far along ridge of bill; eye, brown. Body, Tail and Wings, all blackish brown; 

 breast, mottled greyish and dusky; belly, dusky brown; wing-lining, dusky brown 

 and silvery brown; axillars, dusky brown; feet, dull yellowish to dull brownish 

 red; webs dusky. 



JUVENILE. In first autumn the sexes are alike, and similar to adult female 

 but without whitish patch on back of head; the two light patches on side of 

 head often clear white; breast, pale grey or whitish. During first winter, sexes 

 begin to differentiate, males becoming blacker and females browner; during spring 

 young males acquire white patch on back of head but not the white fore-head- 

 patch, and bill develops in colour and size. By second autumn, after first post- 

 nuptial moult, plumage is practically adult. By third autumn, after second post- 

 nuptial moult, when 27 or 28 months old, the plumage is fully adult. Wing of 

 Both Sexes. As in adult female. Occasionally, young female has the coverts slightly 

 paler. 



SPECIMEN IDENTIFICATION 



MALE. General effect: A medium-sized, black duck, with two white patches 

 on the head, and a peculiar bill. Chief distinguishing features (a) hind toe with 

 lobe, (b) white patch on forehead and another on nape (note that the white 

 feathers on nape are shed at times, leaving an area of black down which is dis- 

 cernible only on close examination), (c) head elongated, forehead following slope 

 of bill, (d) a peculiar varicoloured bill; feathers on ridge of bill extend nearly 

 to nostril, but no feathers on side of bill as in White-winged Scoter (see "De- 

 scription"). 



The lack of white speculum will separate from the White-winged Scoter; 

 and the white head-patches and shape of head and bill from the American 

 Scoter and all other ducks. 



FEMALE. General effect: A medium-sized, dark-brown duck, with a greyish 

 breast. Chief features (a) hind toe with lobe, (b) black crown, two poorly defined, 

 white cheek-patch, and whitish patch on back of head, (c) as in male. 



The lack of white speculum will separate from female White-winged Scoter, 

 and shape of head, feature (c), from female American Scoter and any other duck. 



JUVENILE. The juveniles can be distinguished from the juveniles and adults 

 of other scoters by features (c) and (d) above. See "Description." 



FIELD MARKS 



ON THE WATER. Both sexes appear as large, black, thickset ducks. The 

 males are recognized by the white patches on the nape and forehead and by the 

 peculiar bill, which features are clearly noticeable even at a considerable distance. 



The two whitish face-patches of the dark 

 brown female are usually easily seen. An 

 excellent field mark is the action of the 

 birds when alighting; as the Surf Scoter 

 touches the water the wings are extended 

 upward and so held as the body ploughs 



