MERGANSERS 
111 
only in the highest plumage and quickly fades 
to white after death. Female and young male 
are alike and not distinguishable from parallel 
plumages of the Red-breasted Merganser except 
Gy careful study of details. The head is generally 
a deeper brown and stops with a sharp line 
where it meets the grey of the lower neck. The 
upper throat usually has a well-defined, pure 
white patch. The bill characteristics (Figure 
168) are the only ones for absolute identification. 
The bill of the American is of heavier and less 
slender build, and the nostrils are set near the 
centre of its length instead of well within its 
basal half (Compare with Figure 169). These 
are distinctions that are evident only when both 
species are in hand for direct comparison. The 
feathering of the base of the bill gives an absolute 
distinction. In this species the feathering of 
the sides of the two mandibles extends forward 
an approximately equal distance, instead of the 
upper featheration decidedly over-reaching the 
lower. 
Figure 1G6 
American Merganser; scale, {. 
Field Marks. In adult male, lack of crest, Male Female 
reddish breast-band, and considerably more 
white on sides, flanks, and wings. In flight, the large amount of white on the bend of 
the wing and outer scapulars. It is doubtful whether females may be distinguished in 
life, with certainty, from the Red-breasted Merganser. The darker brown of the head, 
its sharp ending on the neck, and the white throat are suggestive but not determinative 
characters. 
Nesting. In hollow trees or 
rock cavities near water. Nest 
of grasses, etc. 
Distribution. Common in 
New and Old Worlds, nesting 
throughout western Canada, 
north to limit of trees. 
SUBSPECIES. Repre- 
sented in America by the Ameri- 
can Common Merganser Mergus 
merganser americanus (le Grand 
Bec-scie) a very close relative Figure 167 
of the European form. Appearance in flight of American Mergansers. 
This is the larger of the two representatives of this genus, but generally 
frequents the smaller waters, streams, and lakes. It is less common than 
the Red-breasted on the larger lakes or the sea. Otherwise the two birds 
are similar in habit. 
Figure 168 
Bill of American Merganser; scale, F 
Figure 169 
Bill of lled-breasted Merganser; scale, F 
130. Red-breasted Merganser, saw-bill, fish-duck, sheldrake, shelduck. 
le bec-scie A poitrine rousse. Mergus s err a tor. L, 22. Plate XII A. 
Distinctions. Male: similar to last species, but smaller and of lighter build through- 
out, with crest and reddish band across breast and with less white more interrupted with 
black on flank, wings, and neck. The delicate salmon tint of the underbody is present only 
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