350 



MERGANSERS 



JUVENILE. The sexes are alike and similar to the adult female, except 

 the lower throat is white instead of washed with brown; crest, shorter; back, 

 brownish grey. During autumn and winter a prolonged moult takes place; head 

 and neck of young male become mottled with black and sides vermiculated. The 

 tail is renewed in spring but not the wings. By the second November the plumage 

 is fully adult. (See features (c) and (d) below). Wing of Both Sexes. As in adult 

 female. Some young males may be told by superior length of wing and by having 

 the tertials longer, and the inner ones paler grey, than those of adult female, and 

 boldly edged with dusky. 



SPECIMEN IDENTIFICATION 



MALE. WINTER PLUMAGE: General effect: A very large duck, with black head 

 and much white on wings and body. Chief distinguishing features (a) hind toe 

 with lobe, (b) typical merganser bill, long, narrow, cylindrical and toothed, (c) 

 nostril near middle of bill, (d) feathering on side of upper mandible extends for- 

 ward about equal to feathering on side of lower mandible (fig. 54), (e) head 

 without pronounced crest. 



The typical merganser bill will distinguish 

 this bird from the ducks of any other subfamily. 

 In full plumage it is known from the Red-breasted 

 Merganser by its lack of crest and lack of band 

 around upper chest, and by its white chest and 

 sides. In worn or in juvenile plumage, features 

 (c) and (d) will provide means of distinguishing 

 with certainty between the two species. 



AUTUMN AND JUVENILE PLUMAGE: See "Descrip- 

 tions." These juveniles can always be distinguished 

 from the adults and juveniles of the Red-breasted 

 Merganser by features (c) and (d) above. 



FIG. 54 Above, bill of Amer- 

 ican Merganser. Below, bill o] 

 Red-breasted Merganser. The 

 position of the nostril and the 

 featheration at base of bill are 

 important distinguishing fea- 

 tures between these mergansers 

 when in worn or juvenile plu- 

 mage. (Compare also with fig. 

 53). 



FEMALE. General effect: A large brown- 

 headed, grey-backed, white-breasted duck. Chief 

 features, (a), (b), (c) and (d) same as in male, 

 (e) head with elongated crest, (f) large white 

 throat-patch, distinctly outlined against red of 

 cheek and neck, (g) red of upper neck, clearly 

 defined against colour of lower neck. 



The typical merganser bill will prevent 



confusion with the ducks of any other sub- 

 family. In full plumage the clearly defined, white throat-patch and the sharp 

 demarcation of the red and white on neck will separate from female Redbreasted 

 Merganser. In worn or in juvenile plumage, features (c) and (d) will identify. 



FIELD MARKS 



ON THE WATER. The appearance of the male, when sitting, is that of 

 a very large, rakish-looking duck, with much white on the body and a black 

 head. The much smaller, grey-backed female shows the brown colour of head 

 and upper neck sharply defined against the paler colour of lower neck. The 



