270 



DUCK GROUP 



on some of the Irish lakes, where they usually make their appearance 

 as late as December, to depart in the following February. By some 

 ornithologists the name of Cygnus minor is employed for this swan. 

 An immature swan killed (with others) at Aldeburgh, Suffolk, in 1866, 

 has been regarded as a specimen of the American trumpeter-swan 

 {Cygnus buccinator). 



Mute Swan 

 (Cygnus olor). 



From the fact that the cygnets, both wild and domesti- 

 cated, occasionally assume the white plumage of the 

 adult immediately on quitting the downy stage, the 

 mute swan may be regarded as the most specialised member of the 

 group ; being, in fact, a species which is on the way to entirely discard 

 ihe original non-breeding plumage, retained in the young of all other 



swans. It was on the evidence 

 o{ such white cygnets that the so- 

 called Polish swan, which takes its 

 name of Cygnus inunutabilis from 

 this peculiarity, was at one time 

 regarded as a separate species. 



From both the whooper and 

 Bewick's swans the present species 

 is distinguishable at a glance by 

 the presence of the large fleshy 

 •black knob or " berry " surmount- 

 ing the root of the beak. The 

 black extends downwards and 

 backwards as far as the eye, but 

 the rest of the beak is reddish 

 orange, except the tip and a ring 

 round each of the nostrils, which 

 are black, as are also the legs and 

 toes. Cygnets — save for the 

 above-mentioned occasional exceptions — are sooty grey above and paler 

 beneath, with no knob on the beak, which, like the legs and toes, is 

 lead-coloured. Ash-grey and paler below is the colour of the newly 

 hatched chick. From 4^ to 5 feet is the length of the adult bird. 



The mute swan is, however, not distinguished solely by external 

 characters, for its windpipe does not enter a hollow in the breast-bone, 

 as is the case in the two preceding species ; this feature accounting for 

 the lack of voice in the present bird. Another distinctive feature is to 

 be found in the pale green colour of the eggs. 



ML lli SWAN. 



