236 BRITISH SEA BIRDS. 



does not obtain much food upon them. Its food is 

 principally composed of marsh grass, and to obtain 

 this it comes up from the sea to the saltings, and the 

 banks of lakes and tidal rivers. Its flight and 

 actions generally very closely resemble those of the 

 Brent Goose. The note is similar. Nothing is 

 known of the breeding grounds or the nesting 

 habits of the Bernacle Goose. It has, however, 

 been known to breed in confinement. The eggs 



are creamy white. 



SWANS. 



These large and handsome birds form the small 

 but well-defined sub-family Cygninae. They may 

 be distinguished from all other species in the 

 ANATID^E, by having the lores, or space between the 

 eye and the base of the bill, bare of feathers, and 

 by their reticulated tarsus. In this sub-family, as in 

 the Anserinae, the sexes are nearly alike in colour. 

 Swans moult only once in the year, in autumn. 

 The young birds known as Cygnets are hatched 

 covered with down, and able to swim. In first 

 plumage they are uniform grayish - brown ; and, 

 unlike the Geese, they appear not to undergo any 

 moult during their first autumn, but after the moult, 

 which takes place in their second autumn, they 

 acquire the pure white plumage of the adult. 

 Although this sub-family contains but seven species, 

 probably all referable to one genus, its distribution 

 is wide, embracing the Palaearctic, Nearctic, Neo- 

 tropical, and Australian regions. Besides the Mute 



