224 THE PHILOSOPHY OF BIRDS' RESTS. 



which is so strictly analogous to the house-building of 

 savage man. In support of the view that birds learn 

 and improve in nest-building, it may be mentioned, 

 that the celebrated American observer, Wilson, strongly 

 insists on the variety in the nests of birds of the same 

 species, some being so much better finished than others ; 

 and he believes that the less perfect nests are built by the 

 younger , the more perfect by the older birds. 



Again, we always assume that because a nest ap- 

 pears to us delicately and artfully built, that it there- 

 fore requires much special knowledge and acquired 

 skill (or their substitute, 'instinct) in the bird who 

 builds it. We forget that it is formed twig by twig 

 and fibre by fibre, rudely enough at first, but crevices 

 and irregularities, which must seem huge gaps and 

 chasms in the eyes of the little builders, are filled up 

 by twigs and stalks pushed in by slender beak and 

 active foot, and that the wool, feathers, or horsehair 

 are laid thread by thread, so that the result seems a 

 marvel of ingenuity to us, just as would the rudest 

 Indian hut to a native of Brobdignag. 



Levaillant has given an account of the process of nest- 

 building by a little African warbler, which cufficiently 

 shows that a very beautiful structure may be produced 

 with very little art. The foundation was laid of moss 

 and flax interwoven with grass and tufts of cotton, and 

 presented a rude mass, five or six inches in diameter, 

 and four inches thick. This was pressed and trampled 

 down repeatedly, so as at last to make it into a kind of 

 felt. The birds pressed it with their bodies ; turning 



