126 THE NESTS AND EGGS OF BRITISH BIRDS. 



The nest is large, and made externally of dry grass, fine 

 twigs, and sometimes a little moss or a few dead leaves. 

 Then a lining of mud is inserted, which is finally finished 

 off with a second layer of wet, rotten wood, obtained 

 from decaying timber in the vicinity. Very often the 

 nest remains empty for a day or so after it is finished. 

 The Song Thrush is a close sitter, remaining brooding 

 over the eggs until driven from them. When disturbed 

 both parents often become very noisy and anxious for 

 the safety of their home. 



RANGE OF EGG COLOURATION AND MEASUREMENT : 

 The eggs of the Song Thrush are four or five in number, 

 very exceptionally six. They are of a clear turquoise- 

 blue in ground colour, more or less thickly spotted and 

 speckled with dark blackish-brown, and with a few 

 underlying markings of similar character of ink-gray. 

 The spots vary a good deal in size, some being round, 

 others irregular in shape, and most are distributed over 

 the larger end of the egg. Some varieties are blotched 

 rather than spotted with paler brown ; others are with- 

 out markings at all. They also vary considerably in 

 shape and size. Average measurement, ro inch in 

 length, by '8 inch in breadth. Incubation, performed 

 mostly by the female, lasts from thirteen to fifteen days. 



DIAGNOSTIC CHARACTERS: The turquoise-blue ground 

 colour and nearly black spots readily distinguish the 

 eggs of the Song Thrush from those of all other British 

 species. The nest also is unique. 



