BIRDS' NESTS AND EGGS 359 



instinctively, and with no instruction ? If man is so helpless 

 in such a case, why should not the bird be the same ? The 

 same remarks equally apply to a bird's song and the language 

 of mankind each have to be learnt ! 



A bird's mental powers advance towards maturity 

 much more quickly than in the human species. A young 

 bird three or four days old is capable of considerable powers 

 of memory and observation, and during the time that elapses 

 in which it is in the nest it has ample opportunity of gaining 

 an insight into the architecture peculiar to its species. It 

 sees the position of the nest, it notes the materials, and when 

 it requires one for itself, is it so very extraordinary that, 

 profiting by such experience, it builds one on the same plan ? 

 I will go so far as to say that a female Chaffinch, for instance, 

 hatched in a nest amongst the hawthorns, studded with bits 

 of white paper, always chooses a similar locality and similar 

 materials when it comes to build one for itself ! Again, birds 

 are gifted with amazing powers of memory and observation ; 

 they often return to the place of their birth the following 

 season, and possibly see the old home many times ere they 

 want one for themselves. Further, we know that some birds 

 do not breed for several seasons after they are hatched, and 

 consequently see the older birds at work, and profit by the 

 experience. The nests they eventually build may, and often 

 do, vary from the original type in many slight particulars ; 

 and it is by these trifling variations, which, when beneficial, 

 are preserved by natural selection, that birds adapt themselves 

 to any changed conditions of life. Again, there is much 

 evidence to prove that the early efforts of a bird in the art of 

 nest-building are full of imperfections and faults it gains 

 proficiency by experience, and the best nests are made by the 

 oldest birds. At least five per cent of the nests of any one 

 species selected for comparison are carelessly made and lack 

 the usual degree of finish. 



