SEA DUCKS 
97 
148, Greater Scaup Duck, scaup duck, bluebill. broad-bill, lake bluebill. 
le grand MORiLLON. Nyroca marila. L, 18-50. Like a larger edition of the Lesser Scaup 
Duck shown on Plate X A. 
Distinctions. Difficult to separate from the Lesser Scaup, but larger. Male with 
greenish instead of purple reflections on head. In any plumage except occasional young 
birds, distinguished from the Lesser Scaup 
by the white to near-white on the outer 
webs of the inner primaries (Figure 143, 
compare with Figure 144). In the Lesser 
Scaup this light spot may be represented 
by a pale area, but it does not reach the 
clear white of this species. The females 
resemble the females of several other 
species, but can be separated from all 
except the female Lesser Scaup and the 
lling-neck by the white spot at base of the 
bill, and from the latter, together with the 
Redhead and Canvas-back, by the white 
instead of grey speculum. 
Field Marks. In general the adult male 
Scaups appear black for the front half of 
the body and white for the remainder, a 
colour pattern visible at a considerable distance. At rest, distinguished from the male 
Ring-neck by light instead of black back; in flight, in any plumage by white instead of 
grey speculum. .An experienced eye can sometimes tell the two Scaups apart in life by 
the white on the primaries as above, otherwise, as small differences in size are very 
deceptive, they are probably inseparable in the field. The female is distinct from all white- 
bellied brown ducks except the Lesser Scaup and the Ring-neck by the white spot at the 
base of the bill, and from the latter and the Redhead and Canvas-back by the white 
instead of grey speculum. 
Nesting. On the ground, near grassy ponds. 
Distribution. Common to New and Old Worlds. In America, across the continent. 
Many of our breeding records for this species have been confused with the Lesser Scaup 
Duck, but this is a more northern species. We have no authenticated nesting record from 
the prairies or British Columbia where it seems to be a migrant only. Known to nest 
north at least as far as Churchill and Great Slave Lake. It is more common in migration 
on the coast than in the interior. 
Much information founded on accurate specific identification is 
desired as to the occurrence, nesting, and migration of this species. It is 
more of an open or large water bird than the Lesser Scaup, earlier in spring 
and later in autumn. 
149. Lesser Scaup Duck, bluebill. broad-bill. little bluebill. marsh; 
bluebill. le petit morillon. Nyroca affinis. L, 16-50. Plate X A. 
Distinctions. Difficult to separate from 
the Greater Scaup, though slightly smaller. 
Male: with purplish instead of greenish 
reflections on head. In any plumage 
except occasional young birds distinguished 
from the Greater by the absence of white 
or near- white on the outer web of the inner 
primaries (Figure 144, compare with 143). 
In this species this area may pale a little, 
but it does not acliieve the whiteness of 
the Greater Scaup. The female resembles 
the female of several other species, but 
may be separated from all except the 
Ring-neck by the white spot at base of bill 
and from that species together with the 
Redhead and Canvas-back by the white 
instead of grey speculum. 
Figure 144 
Wing of Lesser Scaup Duck; 
scale, about 
Figure 143 
Wing of Greater Scaup Duck; 
scale, about J. 
