OPEN NESTS 189 



stages (as in fact do those of the majority of Thrushes 

 and Ouzels) before it is completed, as we pointed out 

 twenty years ago.^ The first stage consists of a 

 structure formed of coarse grass, amongst which a 

 few twigs are sometimes woven round the rim or 

 sides, a little moss, and dead leaves. The second 

 stage sees this loose cup firmly cemented together 

 inside with a thick plaster of mud or clay. The third 

 or final stage brings the nest to completion by a thick 

 lining of finer grasses arranged very neatly and 

 smoothly. A divergence from this type is presented 

 in the nest of the Song Thrush (Turdus musicus), 

 which, however, may fairly be said to pass through 

 the triple stages. The first two are very similar to 

 those which the nests of the majority of Thrushes 

 undergo, but after the mud lining is inserted a second 

 lining is formed, this time composed of wet rotten 

 wood, which is very skilfully manipulated, so that 

 when dry it is almost as smooth as an earthenware 

 vessel. Then some of the species in the present 

 sub-family build more or less concealed nests on the 

 ground — a type of architecture which we have 

 already illustrated by the nests of the Robin, the 

 Nightingale, and so forth. There are, however, 

 certain other genera in which the birds more or 

 less habitually nest upon the open ground amongst 

 herbage. The Whinchat (Pratincola rubetra) is one 

 of the most familiar examples. This bird very often 

 ^ A History of British Birds, i. p. 241, 



