A THEORY 169 



of these assumptions is that birds, in early times, 

 made no nests, and the second that the eggs were 

 originally laid upon the ground only. Assuming 

 this, and that these ancient birds, like many modern 

 ones, gave themselves up, during the breeding time, 

 to all sorts of strange, frenzied movements over the 

 ground, I suppose the eggs to have been laid in 

 some place which had been the scene of such move- 

 ments. For, by a natural tendency, birds, like 

 other animals, get to connect a certain act with 

 a certain place, or with certain places. Thus they 

 are wont to roost in the same tree, and often on 

 the same bough of it, to bathe in the same pool 

 or bend of the stream, &c. &c. In accordance with 

 this disposition, their antics, or love-frenzies, would 

 have tended to become localised also ; the places 

 where they had been most frequently indulged in 

 would have called up, by association, the nuptial 

 feelings, and, consequently, the eggs would have 

 been more likely to have been laid in such places 

 than in other ones having no special significance. 

 Like every other act that is often repeated, this one 

 of laying in a certain spot would have passed into a 

 habit, and thus the place of mutual dalliance — per- 

 haps of pairing, also — would have become the place 

 of laying, therefore the potential nest. Having got 

 thus far, let us now suppose that one chief form 

 of these frenzied movements, which I suppose to 

 have been indulged in by both sexes, was a rolling, 

 buzzing, or spinning round upon the ground, by 

 which means the bird so acting produced, like the 

 peewit, a greater or lesser depression in it. If the 

 eggs were laid in the depression so formed, they 



