1 68 BIRD LIFE GLIMPSES 



As usual, it has been assumed that this is so, because 

 here, as in other cases, it is impossible, in field 

 observation, to distinguish the one sex from the 

 other, and to assume is a much easier process than 

 to find out. Immediately after coition, however, 

 one has both the male and the female bird before 

 one, and under these circumstances I have seen 

 them both act in the same way, as just described. 

 It is true that the actions of the female were less 

 pronounced than those of the male, but it does not 

 follow that this is always the case, and, moreover, it 

 is of no great importance if it is. The essential 

 fact is that both the sexes go through the same 

 movements, and, therefore, if these movements are, 

 as I believe them to be, the basis of sexual display, 

 one can see why, in some cases, there might be an 

 inter-sexual display, and, as a consequence, an inter- 

 sexual selection. But I leave this question, which 

 has been profoundly neglected, to come to another. 

 In the passage I have quoted, the term " false nest " 

 is put in inverted commas, showing, I suppose, that 

 it has often been used, and, consequently, that the 

 close resemblance of the false nest to the real one 

 has been generally recognised. I suggest that the 

 false nest is the real one by which I mean that 

 there is no essential difference in the process by 

 which each is produced ; and, further, that the 

 origin of nest-building generally, amongst birds, has 

 been the excited nervous actions to which the 

 warmth of the sexual feelings give rise, and the 

 activity of the generative organs. 



My theory is based upon two assumptions, neither 

 of which, I think, is in itself improbable. The first 



