348 A HISTORY OF BIRDS 



be familiar to all. In some species at any rate, it is significant 

 that the females engage in elaborate dances when apparently 

 under the influence of sexual excitement. This has been 

 established, at any rate, in the case of the Greater and Lesser 

 Birds of Paradise. These birds congregate for this purpose 

 apart from the males, which, as we have remarked, hold danc- 

 ing parties or " saccaleli " of their own. But this by the way. 



To continue the tale of Mr. Howard's objections to the sexual 

 selection theory. " The ultimate production," he says, " of the 

 most healthy and most beautiful offspring by the selection [by 

 the females] of certain males is, without a corresponding selection 

 [by the males] amongst the females, impossible, and of the 

 existence of such selection in any form there is no evidence." 



But is this really so ? In the first place he is arguing, ap- 

 parently, solely on deductions drawn from • a study of the 

 Warblers, wherein there are little or no sexual differences, the 

 males indeed are, in some cases, duller than the females. That 

 the males in this group make no selection, but accept the first 

 female that comes in their way, is surely an assumption. 

 Further, since the theory of sexual selection as a whole is 

 challenged, and not merely as applied to the Warblers, it is 

 legitimate to point out that it is a further assumption to sup- 

 pose that the mating of dull females with brightly coloured 

 males would never result in a gradual increase of beauty by the 

 males, since such increase has actually taken place in the 

 Pheasants and Peacocks and Birds of Paradise, for example. 

 In the Warblers he believes he has found convincing proof of 

 the futility of the sexual selection hypothesis, since he writes : 

 " Here, then, the impotency of sexual selection becomes ap- 

 parent, for unless the females that choose the more beautiful 

 males are themselves the more beautiful of the females, they 

 will neutralise the effect of their own selection ". The Peacock 

 and the Bird of Paradise disprove this, or rather they show 

 that brilliantly coloured plumage may be transmitted to the 

 males alone — leaving the females dull coloured. We may 

 further assume that should a vigorous cock pair with a hen of 

 feeble constitution his male offspring will suffer. While this 

 disparity in the coloration of the sexes obtains, Mr. Howard 

 seems to imply that this decorative plumage of the males is 

 transmitted through the medium of maternal impressions on 



