COURTSHIP AND SEX 179 



lifting first one and then the other foot, raising one side of 

 the body and then the other " in a way to exhibit his iri- 

 descence in different lights." What Darwin described in a 

 red tumbler, " walking with its wings raised and arched in 

 an elegant manner," is very common, and along with 

 specificity of behaviour we must also note that genera very 

 different from one another may share the same peculiar 

 habits. 



It is of interest to note that particular kinds of behaviour 

 marked in courtship may also be exhibited when the bird is 

 emotionally excited in other connections. Thus Whitman 

 notes that the raising of the tail to 45° or more is exhibited by 

 the male Geopelia humeralis when he is trying to drive away 

 another cock as well as when he is displaying before his 

 desired mate. 



The rhythmic repetition of movements — seen in bobbing 

 and curtseying, swaying the body from side to side, lifting 

 the feet alternately — may have, especially when accompanied 

 by cooing, a suggestive effect on the female, just as opening 

 the gape wide suggests to the female that she should put her 

 mouth in. 



That the male seeks to arouse first the interest and then 

 the excitement of the female is certain ; that other males are 

 aware of the sexual significance of the preliminaries is also 

 certain ; the error to be avoided is supposing that the male 

 is directing his behaviour in detail towards the satisfaction 

 of the sexual impulse. The behaviour exhibited in the 

 courtship ceremonial is instinctive, specific for the race, and 

 the outcome, doubtless, of a long process of selection in 

 which ineffective displays were eliminated. 



In some cases, such as the bronze-wing, the male drives 

 and charges the female, and there is no doubt that this means 

 " Go to the nest." The driving is often accompanied by 

 the utterance of the " nest-call," which is characteristic also 

 of the incubation-period. The question rises whether the 

 nest is not primarily the stage on which sexual union is 

 consummated, a theory that would make the driving and 

 charging more intelligible. 



