BRITAIN'S BIRDS AND THEIR NESTS. 153 



years ago. Injured birds occasionally remain there during 

 the summer at the present time. The nest is a large 

 heap of herbage, usually on an islet in a lake. The eggs 

 are up to seven in number, and yellowish white or pale 

 brownish yellow in colour. 



THE MUTE SWAN 



(Cygnus olor). 



Most of the Swans we see are feral or escaped ex- 

 amples of this introduced species, best recognised by the 

 conspicuous black tubercle at the base of the bill. The 

 Mute Swan is said to have been introduced as long ago 

 as the reign of Richard Cceur-de-Lion, and it is now widely 

 distributed, and is practically wild in some parts. We 

 may therefore accord it passing mention as a ' naturalised 

 citizen,"* like the Pheasant and the Red-legged Partridge. 

 It is probably also an occasional winter visitor from 

 Scandinavia. Its nesting habits are like those of the 

 Whooper Swan, but the eggs are greenish white. The 

 gray plumage of the goslings is well known. 



