1 82 BIRD LIFE GLIMPSES 



we can understand why it should, in some cases, 

 have retained its original character, in this respect. 



What, now, is the real nature of those frenzied 

 motions in birds, during the breeding season, before 

 they have passed, either into what may properly be 

 called courting antics, or the process of building a 

 nest ? I have described what the peewit actually 

 does, and I suggest that the rolling of a single bird 

 dijffers only, in its essential character, from actual 

 coition, by the fact of its being singly performed, 

 and that, thus, the primary sexual instinct {der 

 thieriscbe Trieb) directly gives birth to the secon- 

 dary, nest-building one. It is true that the pair- 

 ing, when I saw it, did not take place on the same 

 spot where the rolling afterwards did. Nevertheless, 

 the distance was not great, and it varied considerably. 

 The run, which preceded the rolling, commenced 

 immediately on the consummation of the nuptial 

 rite, as though arising from the excitation of it — as 

 may be seen with other birds; and if this run, which 

 varied in length, were to become shorter and ulti- 

 mately to be eliminated altogether, the bird would 

 then be pairing, rolling, and at last, as I believe, 

 laying its eggs in one and the same place. ^ Suppos- 

 ing this to have been originally the case, then the 

 early nest would have been put to two uses, that of 

 a thalamum and that of a cradle, and to these two 

 uses it is in some cases put now, as I have myself 

 seen. That out of one thing having two uses — 

 " the bed contrived a double debt to pay " — there 

 should have come to be two things, each having 



^ The female peewit, it must be remembered, acted in much the 

 same way as the male, and the sexual antics of many birds seem 

 to be identical in both sexes. 



