THE PHILOSOPHY OF BIRDS' NESTS. 223 



organization is best adapted to put together with cele- 

 rity and ease. It has, however, been objected that 

 observation, imitation, or memory, can have nothing 

 to do with a bird's architectural powers, because the 

 young birds, which in England are born in May or 

 June, will proceed in the following April or May to 

 build a nest as perfect and as beautiful as that in 

 which it was hatched, although it could never have 

 seen one built. But surely the young birds before they 

 left the nest had ample opportunities of observing its 

 form, its size, its position, the materials of which 

 it was constructed, and the manner in which those 

 materials were arranged. Memory would retain these 

 observations till the following spring, when the ma- 

 terials would come in their way during their daily 

 search for food, and it seems highly probable that the 

 older birds would begin building first, and that those 

 born the preceding summer would follow their ex- 

 ample, learning from them how the foundations of the 

 nest are laid and the materials put together. Again, 

 we have no right to assume that young birds gener- 

 ally pair together. It seems more probable that in 

 each pair there is frequently only one bird born the 

 preceding summer, who would be guided, to some ex- 

 tent, by its partner. At all events, till the crucial 

 experiment is made, and a pair of birds raised from 

 the egg, without ever seeing a nest, are shown to 

 be capable of making one exactly of the parental type, 

 I do not think we are justified in calling in the aid 

 of an unknown and mysterious faculty to do that 



