174 Sex Habits of the Great Crested Grebe. 



of Egypt. I noticed, however, in my study of the nuptial 

 habits of the Blackcock, that when one of the hens had paired 

 with any selected male, she immediately flew away, and was 

 not accompanied by the latter.* This, at first sight, may 

 seem strange, in either case, but, on reflection, one can under- 

 stand it. The hen has become accustomed to repair to a 

 certain place, for a certain purpose, with which her mind, 

 at that time, is fully occupied. Consequently when that 

 purpose had been fulfilled she would have the feeling that all 

 was now done which she had come to that place to get done 

 (the feeling of completion), which would, in itself, suggest 

 leaving it, and, moreover, this would be the readiest way to 

 avoid further solicitation, which would now be distasteful to 

 her. When the want again arose, however, it would be, as 

 before, in association with the place, a return to which would 

 be, for her, by custom, a necessity. It would therefore be 

 no advantage for the male of her then, or at-any-time choice, 

 to accompany her, and, his want also having been satisfied, 

 he would not, at the moment, feel any stimulus to do so, 

 beyond that which prompts either one of any mated pair of 

 birds to follow the other, which, however, does not always 

 act immediately. But this prompting would now be controlled 

 by a special instinct of what we may call gregarious or social 

 or public courtship, at a certain place, and of waiting at that 

 place, for the hens to come to it. Those males who most 

 duly stayed on the spot would have the best chance of being 

 frequently chosen, so that the habit and the advantages 

 conferred by it would mutually strengthen each other. A 

 separative influence, therefore, would now be set up between 

 the sexes, which would lead to the domestic activities falling 

 upon the female alone, whilst the energies of the male would 

 be solely centred upon courtship. Under the earlier and, still, 

 more common form of sexual selection, we see, indeed, a 

 tendency towards this specialisation of duties, but it is weakly 

 carried out, and often more or less completely in abeyance. 

 For its full (and, no doubt, highly advantageous) development 

 it was necessary that the primitive conjugal shackle should be 

 broken, which, by the full Darwinian extension of the prin- 

 ciple, has, at length, been accomplished. 



The above speculations arise legitimately out of the 

 subject of this paper, for how, when once the pairs are\mited, 

 can sexual selection, in the ordinary sense of it, apply, in the 

 case of these Grebes, who are not only monogamous, but. in 

 my opinion, mate for life? Yet, if the selective principle 

 does not then obtain, how are we to explain their elaborate 

 and diverse conjugal posings, etc., which would, in that case, 



* Zool., July, 1910, pp. 249-50, 252. 



