Family ANATIDAE. 



Tadorna tadorna (L.) Common Sheld-Duck. 



(Plate 181, fig. a-b). 

 (Siiouckaert: Avifauna Necrlandica, p. 124, No. 296). 



Colour of surface of shell: 



Average dimensions: 

 Average weight of shell : 

 Texture of shell: 

 Shape : 



Nest: 



Down: 



Small feathers: 



Site of nest: 



Number of eggs: 

 Breeding season: 

 Duration of incubation : 



more or less creamy white; yellowish with 

 a faint reddish tinge. 



66 X 47 millimetres. 



about 8 grams. 



fine and smooth. 



as a rule oval. 



consists mainly of down, with some vege- 

 table material as bedding. 



light pearl grey. 



white; topped broadly black or reddish brown. 



in rabbit burrows; among sand-elymus grass, 

 under duue-thorns, etc.; also in artificial 

 burrows made for the purpose. 



usually 7—10 (sometimes more). 



May, June. 



about 28 days. 



