230 Habit and Instinct. 



Further observations under varied test conditions are 

 needed to decide the question one way or the other. 



With regard to the truly instinctive nature of the 

 activities of the dance, of antics, of strange performances, 

 and of aerial evolutions there is not much evidence. We 

 cannot say with any certainty whether they have been 

 wrought into the congenital tissue of bird life, or are ac- 

 quired habits transmitted through the influence of tradition, 

 like so many of the social customs of mankind. Might it 

 not be possible to bring up broods of prairie hens under 

 conditions which should exclude the conservative influence 

 of tradition ? If they went through all the antics of the 

 dance under such circumstances, this would be definite 

 evidence of the truly instinctive nature of the performance. 



It is now time to summarize. There are certain 

 activities observable among birds during the pairing 

 season. These are certainly habitual, and in some cases 

 instinctive. Whether they are instinctive in all cases 

 we do not yet know. They may be kept definite through 

 the influence of tradition. Even under tradition they 

 may, if they chance to be correlated with exceptional 

 vigour, be rendered instinctive through natural selection 

 by the elimination of those who fail in vigour. They 

 may also be rendered instinctive through sexual selection 

 by preferential mating if it can be shown conclusively 

 that choice is exercised, and that some are thereby excluded 

 from mating. They may, again, be rendered instinctive 

 through the hereditary transmission of acquired activity, 

 in which case the definiteness of the performance must 

 presumably be due to some form of intelligent selection. 

 If they be regarded as expressions of sexual emotion, 

 such expression may probably have suggestive value, and 

 serve to evoke an answering emotion. In this case the 



