REPRODUCTION— NIDIFICATION 179 



{Myopsittacus monachus), the only Parrot, by the way, which 

 builds a nest, all other members of the order nesting in holes 

 in trees ; thus the domed nest in this case is significant. 



The transition from the platform of twigs to the more 

 highly finished nests such as we must now pass on to examine 

 may well be studied in the work of the Hawfinch {Coccothraustes 

 vulgaris) and the Bullfinch {Pyrrhula vulgaris), which to a 

 platform of twigs adds a neatly wrought central cup composed 

 of rootlets and fine hair. From nests such as these we may 

 pass, by a series of infinite gradations, to cup-shaped structures 

 of exquisite beauty, composed entirely of the finest materials. 

 To follow up these gradations in detail would be an almost 

 impossible task ; suffice it to say that we find in the earlier 

 phases of this evolution that mud is a material commonly used. 

 This fact is of no small significance, since, as we shall show 

 later, it is to this habit that the use of mud exclusively for 

 building material owes its origin. 



The larger Thrushes all employ mud as an agent in the 

 construction of their nests, which are composed of sticks, roots 

 and moss, held together by an admixture of clay, while the 

 interior of the nest is cup-shaped and lined with fine roots and 

 grass. But the Common Thrush {Turdus musicus) has become 

 an expert mason, lining its nest with an admixture of mud, 

 rotten wood and cow-dung in varying proportions. So per- 

 fectly is this plaster-work done that during wet seasons the 

 nest often becomes filled with water, to the destruction of the 

 eggs of course. As the evolution of the nest proceeds the use 

 both of sticks and mud is discarded, the whole structure being 

 composed simply of deftly interwoven root-fibres, grass and 

 moss, with a lining of feathers and fine hairs, commonly pro- 

 cured from the tails of horses. The nest of our Common 

 Redstart {Ruticilla phanicurus) answers to this description. 

 More perfect and more beautiful are the nests of the Goldfinch 

 {Carduelis elegans) and of the Chaffinch {Fringilla coelebs'), 

 the former choosing fine twigs of fir, fine roots and wool, 

 lining the whole with willow-down, feathers and hair. The 

 last-named species is a yet more skilful architect. Wool ap- 

 pears to form the staple building material, and into this moss 

 and lichens of various colours are dexterously woven, producing 

 a shapely cup of uniform texture and singular beauty. Extern- 



