173 

 SEX HABITS OF THE GREAT CRESTED GREBE. 



EDMUND SELOUS. 



{Co7ttinued from The Naturalist for ig20, p. 328). 



All this would, of course, apply equally to the male, the 

 demands of the one sex reacting on those of the other, till 

 what had once been the nesting territory of either a single, 

 or, perhaps, of various pairs of birds, would have become 

 transformed into a place where a number of males met together, 

 to court any arriving female. In the latter, or even perhaps 

 in both cases, it is possible that the standing -place, which 

 each male separately occupies on such an assembly-ground, 

 may correspond to the ancient ' headquarters ' of the nesting 

 territory, or, at least, represent a continuance of the habit of 

 having such a special resort, as to which Howard's work, 

 ' The British Warblers,' may be consulted. For, in any 

 transition, such habits belonging to the old state of things as 

 could be adapted to the new one would be likely to remain, 

 rather than that similar new ones should establish themselves 

 about the central change. Thus one might expect that as 

 the females, in the case supposed, became ready to lay their 

 eggs, places suitable for this would again be chosen on or 

 near the old sites, but there might be a check to this, since 

 what had once become an assembly -ground would be likely 

 to remain so during the whole of the breeding -season. This 

 is in accordance with my own observations, so far at least, 

 as the males are concerned, and a space thus occupied would 

 not be well fitted for the performance of the domestic duties, 

 at least in the case of some ground-laying species. Numbers, 

 however, and the amount of space available, would be now the 

 governing factors. 



In this way, merely through an increase in the numbers of 

 any monogamous species, I can understand what had once 

 been the nesting territory of one or more pairs, passing into a 

 general assembly -ground, for the purpose of courtship, and 

 this habit, once formed, might continue, though the original 

 cause of it had ceased to exist. This, as explained, would 

 bring sexual selection as between individuals — which is 

 Darwinian sexual selection — into play,* but why should the 

 latter imply polygamy, or even, in certain cases, have attained 

 to promiscuity? This seems more difficult to explain, since, 

 when once a choice had been made, there would seem to be 

 no reason why the earlier monogamous instinct should not 

 reassert itself, with the result of a hasty return to the flesh-pots 



* Darwinian sexual selection is, I believe, largely nullified where 

 monogamous species are concerned, through their habit of pairing for life. 



1921 May 1 



