MUTE SWAN 85 



DESCRIPTIVE CHARACTERS. 



PLUMAGE. Adult male nuptial. Pure white. 



Adult female nuptial. Similar to the male in plumage. 



Adult winter, male and female. Similar to the nuptial 

 plumage. 



Immature, male and female (cygnet). Greyish-brown, 

 the breast and abdomen being of a lighter shade. 



BEAK. Deep orange colour, except the 'nail,' the nos- 

 trils, and the ' basal protuberance,' which are black. There 

 is also a noticeable patch of black, extending from the 

 front of the eye to the base of the beak. 



FEET. Black. 



IEIDES. Blackish-brown. 



AVERAGE MEASUREMENTS. 



Note. The Mute Swan is the only one of the three 

 species mentioned, which carries its neck with a graceful 

 sigmoid curve, its wing-plumes at the same time being 

 raised and arranged loosely over the back. The whole 

 carriage of the bird is one of pride and dignity. 



The Whooper and Bewick's Swans, on the other hand, 

 assume a stiffer gait ; they move on the water like Geese, 

 with necks straight and backs flattened. 



In the Mute Swan there is no cavity in the upper part 

 of the breast-bone (sternum) to receive a coil of the wind- 

 pipe (trachea). In the adult Whooper the loop of wind-pipe 

 takes a vertical course, in Bewick's, a horizontal course, as 

 it Jies in the sternal cavity. 



The so-called * Polish ' Swans are now looked on as 

 white varieties of the cygnet of the Mute Swans (' Zoolo- 

 gist,' 1887, p. 463, 1888, p. 470, also Cat. B. Brit. Mus., 

 xxvii, p. 38) (Saunders). 



