NON-INDIGENOUS BRITISH BIRDS. 179 



down three feet from the entrance to the burrow. 

 Beyond lining the selected hole copiously with down 

 this Duck makes no nest. 



Range of egg colouration and measurement : 

 The eggs of the Buffel-headed Duck are from six to ten 

 or twelve in number. They are smooth in texture, 

 with some polish, and greenish-gray \\\ colour. Mr. 

 Raine describes his eggs as "warm dull buff colour, 

 with a grayish tinge." Average measurement, 2*0 inches 

 in length, by r45 inch in breadth. Incubation may 

 possibly be performed by both sexes, but the matter 

 still requires determination. The duration of the period 

 is unknown. 



Diagnostic characters : The eggs of the Buffel- 

 headed Duck somewhat closely resemble those of the 

 Gadwall, but the situation of the nest is different, as is 

 also, most probably, the down, although American 

 naturalists have as yet omitted to describe it. Their 

 colour readily distinguishes them from those of the 

 Golden-eye and Barrow's Golden-eye ; they are also 

 smaller. 



Family ANATID^. Genus Claxgula. 



Sub-family FULIGULIN/E. 



GOLDEN-EYE. 



Clangula glaucion {Linnceus). 



(British : Common autumn and winter migrant.) 



Single Brooded. Laying season, May and June. 



Breeding "area : Northern Nearctic and Pala^arctic 

 regions. The Golden-eye breeds in Iceland, and 

 throughout the Arctic and sub-Arctic regions of Europe 

 and Asia up to the limits of forest growth. In Europe 



