122 CASSELL'S BOOK OF BIRDS. 



of the beak are black ; the feet brownish or pure black. This bird is seventy inches long, and one 

 hundred inches broad ; the length of the wing is twenty-seven inches, and of the tail ten to eleven 

 inches; the female is not quite so large. Brehm is of opinion that the Polish Swan (Cygnus 

 immutabilis) of Yarrell, is merely a variety of the above species, but the following extract from a 

 paper, read by Yarrell before the Zoological Society, will give our readers that naturalist's reasons for 

 maintaining that these birds are not identical, although in their appearance, habits, and mode of life, 

 they closely resemble each other. " The London dealers in birds," he says, " have long been in the 

 habit of receiving from the Baltic a large Swan which they distinguish by the name of the Polish Swan. 

 Daring the severe weather of January, 1838, several flocks of these Polish Swans were seen pursuing 

 a southern course along the line of our north-east coast, from Scotland to the mouth of the Thames, 

 and several specimens were obtained. The circumstance of these flocks being seen without any 

 observable difference in the specimens obtained, all of which were distinct from our Mute Swan ; the 

 fact also that the Cygnets, as far as we observed, were of a pure white colour like the parent birds, 

 and did not assume at any age the grey colour borne for the greater part of the first two years by the 

 young of the other species of Swans ; and an anatomical distinction in the form of the cranium, which 

 was described by Mr. Pelerin in the Magazine of Natural History, induce me to consider this Swan 

 as a -distinct species, and in reference to the unchangeable colour of the plumage, I proposed for it 

 the name of Cygnus immutabilis." 



As additional peculiarities of this species, Yarrell notes that " the parent birds were remarkable 

 in having the legs, toes, and their intervening membranes, of a pale ash-grey colour. The black 

 tubercle at the base of the beak was of small size, and there was a slight difference in the nostrils, the 

 elongated openings of which did not reach the black colour at the base of the beak." The Mute 

 Swan, as it has erroneously been called from the fact of its possessing a soft voice very unlike the harsh 

 tones of its wild brethren, utters a somewhat monotonous and plaintive call during the spring, or 

 occasionally later in the season when moving about with its young. Col. Hawker, in his " Sporting 

 Notes," describes this " Swan's melody" as consisting of two notes, C and the minor third E flat, adding 

 that the musician he heard kept working with his head, as though delighted with the sounds he was 

 producing. In England, where these birds live in a state of semi-domestication, they are met with at 

 all seasons. During the period of incubation they live in pairs, and jealously drive away all intruders 

 from the domain they have appropriated for the purpose of building. The nest, which is formed of a 

 mass of reeds and rushes, is placed near the edge of the river or pond, or on an island, and by a most 

 wonderful instinct is frequently raised to a height sufficient to escape a rising of the water even before 

 man himself has observed any indication of such a danger. The eggs are six or seven in number, 

 and have a dull greenish white shell ; their length is about four inches by two inches nine lines broad. 

 During the whole period of incubation, which lasts about six weeks, the male is in constant attendance 

 to guard his spouse, boldly chasing off all intruders, and occasionally taking his place upon the nest. 

 When first hatched, the young follow the mother about in the water, and are frequently carried on her 

 back as she sails along the stream. Speaking of these birds in their wild state, Lloyd says, " In flying 

 they make a strange appearance ; their long necks protrude, and resemble at a distance long lines with 

 black points ; their heavy bodies and triangular wings seeming mere appendages to the prolonged 

 neck. When thus in motion, their wings pass through so few degrees of a circle that, unless seen 

 horizontally, they appear almost quiescent, their movements being widely different from the semicircular 

 sweeps of the Goose. The Swan, when migrating, with a moderate wind in its favour, and mounted 

 high in the air, travels at the rate of one hundred miles or more an hour. I have often timed the 

 flight of the Goose, and found one mile a minute a common rapidity, and when the two birds, in a 

 change of feeding ground, have been flying near each other, the Swan invariably passed with nearly 



