SJVAJVS. . 335 



pressed in the well-known line, rara avis in terris, nigroque simillima cygno, 

 was considered a mere flight of the poetic imagination. Nevertheless, not only- 

 does a black swan exist, but a second species is remarkable for having a black 

 head and neck and a white body. The swans, all of which may be included 

 in the single genus Cygnus, are readily defined as members of the present 

 family characterised by their exceedingly long necks, their naked lores, the simple 

 first toe, and the metatarsus reticulated and shorter than the third toe with the 

 claw. The group as thus defined, indicates not only a genus, but likewise a distinct 

 subfamily. All these birds are of large size, and have the flexible and slender neck 

 as long as, or longer than the body ; while the beak exceeds the head in length, 

 and has its edges parallel, and the terminal nail small. The tail-feathers vary 

 from twenty to twenty-four in number; and, with the exception of the black 

 Australian swan, the plumage is entirely or mainly white in the adult state. The 

 two sexes are nearly alike ; and there is but a single moult. Swans, of which 

 there are comparatively few species, are distributed over the greater part of the 

 world except Africa south of the Sahara, North Australia, and the northern 

 districts of South America. The gracefulness of their form, and especially the 

 beautiful curving of the neck, is proverbial ; and they are all birds of powerful 

 flight, more aquatic in their habits than the geese, but also walking well on land. 

 Frequenting lakes and other inland waters in summer, they often seek the sea in 

 winter; but while some prefer open waters, others, like Bewick's swan, rather 

 favour marshes and narrow rivers. Their food consists of the seeds, stems, and 

 roots of flags and other water-plants, supplemented by insects and molluscs. All 

 the white swans are migratory, and during their migrations fly both by night and 

 day. Like the geese, they are more or less gregarious, especially during the winter ; 

 and they also resemble those birds in pairing apparently for life. Their large 

 untidy nests are placed on the ground, often among tussocks of coarse grass, and 

 contain from three to eight dull whitish eggs. As a rule, the young birds have 

 feathered lores, and a greyish brown plumage. The call-note is loud and trumpet- 

 like. 



At least two species of swans are winter- visitants to the British 

 Whistling Swans. . . 



Islands, while a third occurs in a domesticated state, although 



probably a few wild individuals also arrive. The first of these is the whooper or 

 whistling swan (C. musicus), which belongs to a group of species common to the 

 northern half of both the Old and New Worlds, and characterised by their com- 

 paratively short and rounded tails ; while it is specifically distinguished by the 

 lores and the basal portion of the beak to below the nostrils being yellow, the 

 remainder of the nostrils being black. In length this species reaches 60 inches. The 

 whooper is essentially an Arctic species, breeding chiefly within the Arctic Circle 

 either on the islands in the deltas of the great rivers, or on the lakes of the Siberian 

 tundras. Iceland and the northern parts of Scandinavia are also favourite nesting- 

 haunts of this species, which appears to breed in pairs and not in small flocks. Mr. 

 Hume is of opinion that during its winter migration this species does not, except 

 in unusually severe winters, go as far south as some of its allies, although at times 

 it reaches the Mediterranean Islands, Egypt, Algeria, and Palestine. Eastwards, it 

 visits the Caspian, Persia, Turkestan, China, and Japan, but is unknown in India 



