Family SITTIDAE. 



Sitta europaea caesia Wolf. — Nuthatch. 



(Plate 38, fig. a— c). 

 (Snouckaert: Avifauna Neerlandica, p. 29, No. 63). 



Colour of surface of shell: 

 Colour of spots: 

 Average dimensions: 

 Average weight of shell: 

 Texture of shell: 

 Shape : 

 Nest: 



Site of nest: 



Number of eggs: 

 Breeding season: 

 Duration of incubation: 



milk-white. 



reddish brown, in various shades. 



19.8 X 14.5 millimetres. 



0.134 gram. 



presents no special characteristic. 



ovoidal. 



a heap of vegetable materials as an under- 

 layer for the eggs. 



at from about 3 to 4 Metres from the ground; 

 especially in old Woodpecker nests, the 

 entrance of which is narrowed with earth 

 (mixed with saliva) in proportion to the 

 size of the own body. 



6-9. 



end of April— June. 



about 14 days. 



