22G NYROCA ERYTHROPHTHALMA 



soft prr-ah-ah, brr-ah-ah (Sjostedt, 1910). I am afraid I cannot add anything as I did 

 not hear them calling. 



The trachea is considerably dilated in its middle part, much like that of the Red- 

 crested Pochard, Scaup, White-eye, Golden-eye and Red-breasted Merganser, but 

 the swelling is not as great as in the Red-crested Pochard, though greater than that 

 in the Scaup. The tracheal box is left-sided, the posterior side being almost entirely 

 osseous, while the anterior side is composed of membranous windows supported on 

 bony frames (P. L. Sclater, 1878a). The osseous part is a very hard bony bulb, while 

 the keeled structure has one large membranous window in the middle and a smaller 

 one on each side of it. The large membrane does not seem always to be intact and 

 there is some variation in the structure of the fine bony framework in different in- 

 dividuals. The interior of the membranous chamber connects through a narrow 

 passage with the bulbous portion and also freely with the left bronchus. 



Food. The food has never been carefully studied. The stomach of one in Africa 

 was filled with black laval gravel mixed with what seemed to be Chara algae; an- 

 other had "water plants" mixed with gravel. Those I shot in Uganda in April 

 seemed to be feeding entirely on vegetable food, mostly small blackish seeds about 

 two millimeters in diameter. 



Courtship and Nesting. The courtship seems never to have been observed. 

 All we know is that the nesting season is very irregular and so few nests have been 

 found that adequate descriptions of the site chosen are as good as absent. In East 

 Africa full-grown young were found by Schillings (1905) in July, while in Natal 

 young ten days old were seen on September 18, others in October and November 

 (E. A. Butler, Feilden and Reid, 1882). Eggs were taken in southwestern Africa 

 February 23 (British Museum), while in Cape Colony, Davies (B. Horsbrugh, 1912) 

 found a nest on the 24th of April. Along the Berg River it was "breeding" in 

 September (Layard, 1875-84). When Dr. Osgood was at Maracaibo, Venezuela, in 

 May, 1920, at a big swamp near sea-level these ducks were evidently nesting, for 

 only single male birds and no females were seen. I know nothing more about the 

 season of nesting in South America. Without a doubt it is just as irregular as in 

 Africa. 



The nest which Davies found was in a clump of grass about twenty yards from 

 the water, a long distance for a diving duck. It was "neatly made of grass and a little 

 down" and contained nine eggs. 



The clutch numbers from five to nine and the eggs are smooth in texture, moder- 

 ately glossy, and pale brown to pale cream color. They measure 2 to 2.3 inches 

 (51 to 59 mm.) in length and 1.58 to 1.68 inches (40 to 42.5 mm.) in width (E. W. 

 Oates, 1902; B. Horsbrugh, 1912). 



