Family TETRAONIDAE. 



Lyrurus tetrix (L.) — Black Grouse. 



(Plate 116, fig. a-c). 

 (Snoucl.aert : Avifauna Necrlandica, p. 79, No 180). 



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: 



yellowish, tinged with brown or red. 



rusty brown. 



49.7 X 3G.1 millimetres. 



2.38 grams. 



smooth, with many well visible pores. 



oblong ovoidal. 



consists of a little dry grass and leaves, as 

 a bedding for the clutch. 



in a little hollow in the ground among long 

 grass, heather, low shrubs, among young 

 firs, etc. 



6—12 (sometimes more). 



May, June. 



about 27 days. 



