WATER BIRDS. 93 
black and white, the white lines being about twice as wide as the black ones, the result 
being a very light canvas pattern (whence the name “ White-back”’); rump and upper 
and under tail-coverts black; lower breast and belly white, the latter grayish posteriorly. 
Speculum bluish gray, some of the secondaries white-tipped, two or three of the inner 
ones black-edged. Adult female: Head, neck and upper breast cinnamon or umber 
brown, the throat and face lighter and more rusty; back, sides and flanks grayish brown, 
usually more or less cross-lined with white; rest of under parts white or grayish white. 
Length 20 to 23.50 inches; wing 8.75 to 9.25; culmen 2.10 to 2.50. 
45. Greater Bluebill. Marila marila (Linn.). (148) 
Synonyms: Big Bluebill, Blackhead, Broadbill, Greater Scaup, Raft Duck, Flocking- 
fowl, Shuffler.—Anas marila, Linn., 1761.—Fuligula marila, Steph., 1824.—Fulix marila, 
Bd., 1858, B. B. & R., 1884. 
The adult male is known by its size, dull blue bill, uniform greenish- 
black head and neck, with black nape, and pure white speculum tipped 
with black. The female is similar, but browner, and has a conspicuous 
white face or ‘mask.’ 
Distribution.—North America, breeding far north. South in winter 
to Guatemala. 
This bird is usually confounded with the Lesser Bluebill from which 
it can be discriminated only with difficulty. It is probable that nine- 
tenths of the records for Bluebills relate to the Lesser Bluebill and not 
to the present species, which is much less common, more northern in its 
distribution, and probably the species which most often remains in the 
open waters about the state during the winter. In most respects it is 
impossible to discriminate between the two species and I know of nothing 
peculiar in the habits of the Greater Bluebill which requires mention. 
The only record of its nesting in Michigan is by the late W. H. Collins, 
who found one nest containing three eggs in the summer of 1879. “The 
nest was built in a tuft of flags, and composed of rushes and wild rice 
lined with some down and feathers. It was resting in the water and held 
in place by the tuft of flags in which it was built. I killed the female.” 
(Bull. Nutt. Orn. Club, V. 62). Mr. A. C. Bent states that “The American 
(Greater) Scaup Duck probably breeds sparingly in North Dakota, but 
I have no evidence to prove it, and I am inclined to think that if it occurs 
there at all it is extremely rare.” (Auk, XIX, 1902, 165). The eggs are 
pale buffy olive gray, and average 2.54 by 1.71 inches. 
TECHNICAL DESCRIPTION. 
So similar to the following species, the Lesser Bluebill, that except in two or three par- 
ticulars the same description would answer for both. The most important difference 
is in the size, the present species being decidedly larger, and this is particularly noticeable 
in the width of the bill which ranges from .85 to 1.05 inch, the average being .97, while 
in the Lesser Bluebill the greatest width ranges from .80 to .95 inch, the average being .89. 
In the male of the Greater Bluebill the black of the head and neck always (?) shows a 
greenish gloss, and the flanks are pure white without any cross-lines or spots, while the 
Lesser Bluebill has a purplish gloss on head and neck and the flanks distinctly cross-lined 
with dusky. The females of the two species probably are separable only_by the measure- 
ments. Length 18 to 20 inches; wing 8.25 to 9; culmen 1.85 to 2.20. 
