COURTING DISPLAY INSTINCTS IN BIRDS. 403 



mistaken.* The fact that, speaking generally, such action is 

 more developed in the male does not, in my opinion, tell against 

 my view, for when Miss Haviland says : — " It is not likely that 

 the necessity for amatory exercises, as a way for working off 

 emotions, should have lapsed in one sex and not in the other, 

 especially when the resultant passion to make a nest has persisted 

 so strongly, "t I am quite unable to follow her. I think it is 

 what, prima facie, one might have expected, on the principle of 

 specialisation and division of labour as brought about through 

 natural selection, which would have preserved the " resultant 

 passion," because useful, whilst letting the steps that had led 

 to it lapse because, being no longer so, they now represented 

 waste energy or energy in excess of the bird's capacity. Some 

 check on expenditure there must be, and Nature's retrenchments 

 would be upon the same lines as our own. 



And what is meant here by " necessity " ? Things are only 

 necessary, in evolution, till replaced by other things more 

 necessary — i. e. more beneficial — pro tern. Marvellous instances 

 of this lie before us. The female instincts and organs must once, 

 in every case, have been necessary for the female ant, but they 

 have gone, to make her the worker ant. How much more easily 

 then, might anticking female birds have been turned into non- 

 or less anticking nest-building ones. Also the " amatory exer- 

 cises," assumed by Miss Haviland to be necessary, may not even 

 be of importance. They may be — and very likely are — no more 

 than a by-product, which, as long as it were not detrimental, 

 might continue indefinitely, offering good raw material for 

 natural selection to seize on and make something useful out of. 

 Many of the fine things of higher human nature — romantic 

 love, for example — are but by-products in respect of Nature's 

 main scheme of advance, but, being compatible with it, they go 

 on, and we go on thinking too much of them. 



Miss Haviland does not think that the cock bird often helps 

 the hen in nest-building, and her opinion, in regard to exceptional 

 facts, appears to be that they mean nothing and point nowhere.* 



* See post, pp. 406 (3), 407 (6) (10), 40S (14). I can, however, owing to 

 the exigencies of space, only give marginal references to this and other facts 

 essential to rny argument, and supporting the statements in the text. 



t ' Zoologist,' p. 223. 



I Ibid., p. 225. 



