ANAS IXNDULATA. 



YELLOW- BILLED DUCK OR GEELBEC. 



(Plate 55.) 



Anas undulata, Dubois, Om. Gall., p. 119, pi. lxxvii (1839) ; 

 Salvadori, Cat. Birds Brit. Mus., xxvii, p. 212 (1895) ; Wood- 

 ward, Natal Birds, 209 (1899) ; Reichenow, Vogel Afrikas, i, 

 p. 113 (1900-01) ; Sclater, Ann. S. Afr. Mus., iii, p. 352 (1905) ; 

 Sclater & Stark, Birds of S. Afr., iv, p. 134 (1906). 



Anas xantJwrhyncha, Sharpe's ed. Layard's Birds of S. Afr., p. 755 

 (1875-84) ; NicoUs & Eglington, Sportsman in S. Afr., p. 127 



(1892). 



Description. The bird figured is an adult male. Length about 

 22| in. The sexes in the Yellow-billed Duck resemble each 

 other, but there is a marked difference : the males, besides 

 being distinctly larger and more brightly coloured in the yellow 

 of the beak, have aU the pale edgings of the feathers whiter 

 and the centres darker than the corresponding feathers of the 

 female bird, so that their breasts and flanks have a scaled 

 appearance, whereas in the females and young birds the whole 

 colouring is dingier, the dark brown is lighter, and the centres 

 to the feathers of the under- parts more longitudinal, giving them 

 a more striped appearance. 



These differences are hard to describe, but easy to see if the 

 birds are compared. 



Distribution. This is the common Wild Duck of South Africa, and 

 is found everywhere except, perhaps, in German South-west 

 Africa and the Natal sea-board. It only extends as far west 

 as Angola, but in the east has been recorded from all over Africa 

 as far north as Abyssinia. It is very common in British East 

 Africa. 



Yellow-bill, like most South African duck, are partially 

 migratory, their movements depending on the amount of 

 water there is in their haunts and on the rainfall. 



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