Sex Habits of the Great Crested Grebe. 175 



be so much wasted energy? On the other hand, if selection 

 can act and produce marked results, in the way here supposed, 

 a further development of it does not seem required, and the 

 difficulty is now to explain the existence of Darwinian sexual 

 selection, for that it does exist, amongst birds, my own 

 observations have demonstrated,"" as have those of Professor 

 and Mrs. Peckham, that it does amongst spiders. f But if the 

 passage has come about in the manner suggested by me, then 

 it may be said to have been a fortuitous one — dependent, 

 that is to say, upon an entirely outside factor — and this I 

 take to mean that, in spite of the magnitude of the advance, 

 it was not imperative. 



Further views, of a less enlarged scope, will, and indeed 

 must, arise on the actions of these birds, as recorded in my 

 diary, for, the fact is, their extraordinary habits are a very 

 mine of reflection. 



Feb. 22ND. — In the less reedy parts of the two most con- 

 tiguous reservoirs here, there were, to-day, nine of the Crested 

 Grebes, which I took to consist of four mated couples and a bird 

 over. This was demonstrably so in several cases. Two pairs, 

 for example, I saw dallying, and one of these, at any rate, 

 nebbed — touched bills, at -least, that is to say. It was not 

 carried to the extent of yesterday, as I believe. Here, again, 

 it struck me that the twitches, rather than shakes, of the 

 head, were accessory only to the nebbing, intended or felt by 

 the birds to be so, though overgrown, and become a sort of 

 nervous appanage of it. On Wilston Reservoir, I saw another 

 pair thus acting, and again I felt convinced that the beaks 

 were in contact. So slender are they, however, that, at 

 these distances, it is difficult to be certain that one actually 

 sees the thin lines touch — rather what one does see seems to 

 make this a necessity. 



Several times, to-day, I saw a bird rise precipitately 

 from the water, and fly, for some distance over it. The 

 circumstances, in each case, made it likely that this was a 

 flight from an enemy attacking subaqueously, so that we have 

 here one cause of such flying about as does take place, during 

 the supposed pairing-up time of these Grebes ; for really 

 there is no such process, but only that of the ripening of certain 

 activities in already mated couples. It must, I think 



* Zool., Aug. and Nov., 1906, Feb., May and Oct., 1907. 



* Zool., Nov., 1909, and Jan., Feb., May and July, 1910. 



t I am unable now to refer to the paper itself, but salient extracts 

 from it are given in Professor Poulton's ' The Colours of Animals 

 (International Scientific Series). The facts seem to me as demonstrative 

 as if they had been thought out, and arranged beforehand, by an un- 

 scrupulous advocate of sexual selection, who was also a great magician — ■ 

 or chemist. 



1921 May 1 



