SEXUAL SELECTION— NESTING OF BIRDS. 237 



The materials with which it is made seem very 

 different too. The cup of the nest is small, loosely 

 j)ut together, apparently lined with feathers, and 

 the walls of the structure are prolonged for about 

 eighteen inches, and hang loosely down the side of 

 the suj^porting branch. The whole structure bears 

 some resemblance to the nests of the Hangnests 

 (IcTERiD^), with the exception that the cavity con- 

 taining the eggs is situated on the top. Clearly 

 these New Zealand Chaffinches were at a loss for a 

 design when fabricating their nest. They had no 

 standard to work by, no nests of their own kind to 

 copy, no older birds to give them any instruction, 

 and the result is the abnormal structure I have just 

 described. Perhaps these Chaffinches imitated in 

 some degree the nest of some New Zealand species ; 

 or it may be that the few resemblances this extra- 

 ordinary structure presents to the typical nest of 

 the Palsearctic Chaffinch are the results of memory 

 — the dim remembrance of the nest in which they 

 had been reared, but which had almost been effaced 

 by novel surroundings and changed conditions of 

 life. Any wav, w'e have here, at least, a most 

 interesting and convincing proof that birds do not 

 make their nests by blind instinct, but by imitating 

 the nest in which they were reared, aided largely by 



