EASTERN SPOT-BILLED DUCK or GRAY DUCK 
ANAS ZONORHYNCHA Swinhoe 
(Plate 24) 
Synonymy 
Anas pcecilorhyncha Reichenbach (jiee Forster), Synopsis Avium, Natatores, pi. Ill, 
fig. 1081, 1845. 
Anas zonorhyncha R. Swinhoe, Ibis, ser. 2, vol. 2, p. 394, 1866. 
Vernacular Names 
English: Eastern Spot-billed Duck, Eastern Yellow-billed Duck, Zone-billed Duck, 
Dusky Mallard, Eastern Gray Duck, Yellow-nib. 
French: Canard a bee orange. 
German: Gelbschnabel Ente. 
Japanese: Karugamo. 
DESCRIPTION 
Adult Male: Most like the male of Anas pcecilorhyncha, but the whole under surface except breast 
a nearly uniform gray brown with spots hardly showing at all. Some specimens are much darker 
than others. The upper breast is lighter and more like that of Anas pcecilorhyncha, but is less heavily 
spotted. The head is nearly the same except for the presence of an ill-defined stripe running back 
from the angle of the jaw. Upper surface nearly the same, but mantle more uniform. Speculum 
purple instead of green. Anterior white wing-bar reduced or nearly absent. Posterior white bar 
absent or reduced to a mere line. 
Iris yellow-brown. Bill without the orange patch at base of culmen; tip yellow. Legs and feet 
deep orange. 
Wing 263-293 mm.; bill 50-55; tarsus 43^9. 
Adult Female : Under parts much more streaked and spotted than in the male. Upper side nearly 
the same as in male; colors of soft parts the same; size smaller. 
Wing 255-262 mm.; bill 45-49; tarsus 42^4. 
Immature Specimens: Paler than the female, and with small dusky spots on the under parts. The 
edges of the upper wing-coverts pale; a broad subapical white band across the greater wing-coverts, 
and the outer web of the tertials for the greater part white (Salvadori, 1895). 
Young in Down: Upper side from the forehead to the tail pale olive-brown; a stripe of the same 
color from the base of the culmen through the eye, and another short line under the ear-coverts; 
superciliary stripe, sides of head and neck, throat, crop, and the back edge of the wing, a spot behind 
the wing, and another on the sides of the rump light pale-yellow. Sides and front part of breast, 
almost to the middle, grayish brown ; middle of the under side of the body, dirty, rusty cream-color 
(Hartert, 1920). 
