138 British Birds. 



To England Bewick's Swan is a rarer migrant than the Whooper, but to 

 Scotland and the Hebrides it is a much more frequent visitor, and it visits Ireland 

 occasionally in very large numbers. Its breeding-home is in the tundra of Northern 

 Russia and Siberia and it also nests on the island of Kolguev. The nest is made 

 entirely of moss, and is a large structure, but is smaller than the nest of the Whooper. 

 The eggs are two or three in number, white like those of its larger ally, but smaller 

 and less glossy, measuring about four inches in length. 



The trachea in this species is simple and does not enter the 



keel of the sternum, as in the two precedmg species. 1 he adult 



MUTE SWAN. , . , . , . ,, , ,,,,•,■',,• , , 



bird is white all over, but the bill is ot a reddish-orange colour, 



(Cyguus olor.) 



with a black tip ; the lower mandible is also black as well as the 



lores, base of the upper-mandible, and the nostrils : there is also a black swollen 

 tubercle on the base of the bill, smaller in the female than in the male. The 

 nestlings are of a dull ash}--grey, and the young birds are sot)ty-grey. The so- 

 called Polish Swan (Cvgnus iiiiiiiiitnbilis) is now considered to be merely an albino 

 variety of the Mute Swan, due to captivity. This form has white nestlings, but 

 when the birds are adult, no difference can be detected between them and the 

 ordinar\' Mute Swan, though C. iiiiniutahilis has been said to have the legs and feet 

 ashy grey. In Great Britain the present species is principally known as a domes- 

 ticated bird, but occasionally examples appear to visit us from the Continent, where 

 the Mute Swan is still met with in a wild state. It nests in South Sweden and 

 Central Europe generally, as well as in Southern Russia, as far east as Turkestan. 

 The food of the Mute Swan consists of water-weeds and other aquatic plants, 

 together with small molluscs and water insects. The nest is a huge structure of 

 dead flags and grass, and the eggs, from three to five or six in number, are greenish 

 white : their length is about four-and-a-half inches. 



All the t3'pical Ducks have a narrow lobe on the hind toe, and 



there is a metallic speculum of bright colour on the wings, bv 



TRUE DUCKS. ^.- u . s: .u • 1 Ti 1 u 



which most 01 the species are recognised. 1 he males have a 

 Sub-family 

 ANATIN ¥ bony swelling on the trachea. Several species, if not every 



Duck, moults after the nesting-season is over, the quills even 

 being shed, so that the bird is not able to fly. The brilliant plumage of the breeding- 

 season is discarded, and the male puts on a sober-coloured dress like that of the 

 female, and hides himself away in reed-beds and cjuiet places, until his wings 

 have grown again. Sea-Ducks, like the Eiders, betake themselves to the open sea, 

 where the males collect in large flocks until the moult is completed. 



Besides the species enumerated below, there are several which have obtained a 

 place in the British List, such as the Egyptian Goose (Chfiiulope.v ngyptiaca), the 

 Summer Duck (.:7:.r spoiisa), and the Muscov}- Duck (Cairina iiioscJiiita). These, 

 however, are all species which are frequently kept in captivit}-, and the records of 

 their capture are doubtless those of escaped birds. 



