Family ANATIDAE. 



Aythia ferina (L.) — Common Pochard. ') 



(Plate 187, fig. a-b). 

 (Snouckaert: Avifaiuin Neerlaiidica, p. 128. Nu. 306). 



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 : 



greenish drab (hazel coloured); greyish green. 



62 X 44 iniUimetres. 



6.5 grams. 



fine and smooth. 



usually oval, often bellied; sometimes ellip- 

 tical; rounded off abruptly at both ends. 



consists of vegetable materials, lined with 

 down. 



brownish grey (particularly soft). 



brownish, faintly striped from the centre in 

 an upward direction, a small part of the 

 top being often coloured grey. 



in marshy regions on dense tufts of sedge. 



as a rule 8—10 (sometimes more). 



May. 



about 27 days. 



>) For biological particulars of this species see especially the important 

 article by Mr. Tjeerd de Vries Gzn. in : „Verslagen en Mededcelingen der 

 Nederlandsclie Ornithologisclie Verecniging", No. 4, p. 13 et seq. 



