54 Birds of Colorado 
lining its often bulky nest with down. The eggs are 
said to be rather more greenish in shade than those of 
the Redhead, and to measure 2°50 x 1°75. 
Scaup Duck. Marila marila. 
A.O.U Checklist no 148—Colorado Records—Drew 81, p. 142; 
85, p. 18; Morrison 88, p. 140; 89, p. 165; Cooke 97, pp. 55, 195; 06, 
p. 44; Henderson 03, pp. 107, 110; 09, p. 226; Warren 09, p. 13; 
Felger 09, p. 281. 
Description.—Closely resembling M. affinis—the next species—but 
larger, the head glossed with green instead of purple, and the flanks 
nearly white with but faint traces of the wavy bars. The female 
can be distinguished from that of M. afinis by its larger size. Length 
19-75; wing 9-0; tail 2-80; culmen 2-0; tarsus 1:55. Wing of female 
8-50. 
Distribution.—The northern parts of the Old and New Worlds, south 
in winter ; in America breeding from Minnesota and south-east British 
Columbia north to Alaska; in winter chiefly on the Atlantic coast 
from Massachusetts to Delaware, in the Mississippi Valley, and west- 
wards to southern California. 
The Scaup is rather a rare duck in Colorado. It has been reported 
from Boulder eo. (Henderson) Barr (Hersey), Longmont (Felger), 
Breckenridge (Carter), Coventry in April (Warren), and La Plata 
in fall (Morrison) on migration, while Drew came across it in December 
in San Juan co., at 9,000 feet, so that perhaps it spends the winter 
in the southern part of the State. 
Lesser Scaup Duck. Marila affinis. 
A.O.U. Checklist no 149—Colorado Records—Aiken 72, p. 210; 
Drew 81, p. 142; 85, p. 18; Morrison 88 p. 140; 89, p. 165 ; Cooke 97, 
pp. 18, 56, 195; 06, p. 46; Henderson 03, p. 107; 09, p. 225. 
Description.—Male—Head, neck, front half of the breast, and back 
black ; the sides of the head glossed with purple ; lower-back, rump, 
upper and under tail-coverts, tail and primaries, dusky brown or 
blackish ; middle of the back, scapulars, and some of the upper coverts 
white with narrow wavy bars of dusky ; below white, slightly mottled 
with dusky on the lower abdomen and sides ; wing with a white patch 
on the secondaries forming a speculum ; iris yellow, bill dull bluish 
with nail black, legs slaty. Length 16-5; wing 8-0; tail 2-25; culmen 
1-7; tarsus 1-2. 
The female is chiefly dark brown with a conspicuous white patch at 
the base of the bill, a white chin, speculum and abdomen. The male after 
the breeding season moults to a plumage like the female but darker. 
