AFRICAN YELLOW-BILLED DUCK 
AXAS UNDULATA Dubois 
(Plate 25) 
Synonythy 
Anas flavirostris Smith (nec Vieillot), Cat. South African Mus., p. 36, 1837. 
Anas undulata Dubois, Ornith. Gallerie, p. 119, pi. 77, 1839. 
Anas xanthorhyncha Forster, leones Ined., pi. 72; Descriptiones Animalium, p. 45, 
1844. 
Anas capensis Lichtenstein (nec Gmelin), Verzeiehniss d. Saugethiere und Vogel, 
p. 20, 1842. 
Anas ruppelli Blyth {sic), Journ. Asiatic Soc. Bengal, vol. 24, p. 265, 1856. 
Querquedula xanthorhyncha Sharpe, Ibis, ser. 6, vol. 4, p. 541, 1892. 
Vernacular Names 
English: 'Vellow-billed Duck, African Yellow-billed Duck. 
French: Canard a bee orange. 
German: Gelbschnabel Ente. 
Dutch: Geelbec — (South Africa). 
Arabic: Boumon. 
DESCRIPTION 
Adult Male: General appearance like a female Mallard, but head and neck much darker and 
browner. Margins of the feathers of mantle and scapulars narrowly edged with very pale buff and 
gray. Lesser wing-coverts edged with white, and not plain-colored as in female Mallard. Speculum 
very similar to that of Mallard, varying from purple to green and framed with black and white bars. 
Iris dark brown. Bill orange-yellow, with the middle of the culmen and the nail black. Legs and 
feet dark brown (Neave, 1910) and black, or tinged with yellow according to other writers. 
Wing 246-255 mm.; tarsus 45-46; bill 49-52. 
Female: There is no real difference in the plumage of this sex as far as I have been able to see. The 
head may be slightly less dark and rich in color than in the male. Color of soft parts same as in male. 
Immature Specimens: Very similar, but the heads are apparently browner than in old birds. Mr. 
F. E. Blaauw says the markings of the feathers are less well defined. 
Young in Down : The whole of the under side, including throat and cheeks golden yellow. A dark 
band begins at the base of the bill, widens over the occiput, and becomes narrower over the back of 
the neck to join the brownish black of the upper side. The brown of the upper side runs into the 
yellow of the breast for about a centimeter on each side. A thin black line runs through each eye, 
meeting the brown of the back of the neck. There is a blackish patch over each ear. There is a 
yellow spot on each side of the back at the base of the wings and a yellow streak over each wing, also 
a yellow spot on each side of the back at the base of the tail and one above each thigh. The legs. 
