TENTH ANNUAL REPORT. 



169 



BLACK-NECKED SWANS. 



except for the head and the major part of the neck, which are 

 velvety blackish brown. This is relieved by a line of white feath- 

 ers about the eye, extending backward as a w-ell-defined stripe 

 across the entire head. While in the northern wdiite species the 

 bill is often decorated with bright yellow, in the Black-Necked, 

 as in the Black Swan, the presence of a darker color in the feath- 

 ers seems correlated with a change in the bill pigment from yel- 

 low to red. A full-grown bird of the present species has the cere 

 or fleshy base of the bill swollen and enlarged above into a knob 

 or an irregular bunch of caruncles stained a vivid scarlet. This 

 bird is somewhat larger than the Black Swan, with a stouter, 

 shorter neck, and, though more striking in appearance, is less 

 graceful wdien swimming. 



From the young birds we may, perhaps, get a hint of the devel- 

 opment of color in this species. The white feathers of the body 

 are tipped with rusty brown, and, still more significant, the tips 

 of the primaries are chocolate brown. This may be a vanishing 

 hint of a former closer relationship betw^een this swan and the 

 black wing-tipped coscoroba. \\'hether the presence of black in 

 the plumage of the adults of this species and the Australian spe- 



