BRITISH WARBLERS 



to reduce the emotional behaviour of the group to some order 

 rather than a definite contribution to our knowledge of the 

 subject. Why do I attribute a certain level of emotional 

 development to such and such a species ? Knowing, as we do, 

 that in the case of human emotion a stimulus of an appro- 

 priate kind is necessary to produce a definite response, we can 

 scarcely doubt that the same is true of the primary emotions 

 of the lower animals. And since all knowledge of the emotion 

 of a bird, in its subjective aspect, is beyond human under- 

 standing, how can we be sure that the comparisons are made 

 under corresponding conditions, and are we therefore justified 

 in even attempting to decide as to the relative position this 

 and this species ought to occupy in any scale of emotion ? I 

 grant the difficulty, and even admit that the same individual 

 does not always respond actively when under the influence of 

 sexual or parental emotion. Perhaps my conclusions may be 

 said to be based more upon impressions gained from a long 

 acquaintance with the different species, than upon anything in 

 the nature of tangible fact. And yet extravagant antics, 

 which comprise an outstretching, flapping, and fluttering of 

 wings, a spreading and raising of the tail, peculiar contortions 

 of the body, and an equally peculiar employment of the vocal 

 powers, are surely sufficient reason for assigning to the actor a 

 different level in an emotional scale from one whose move- 

 ments attract but little attention or excite but little wonder. 

 Starting thus with the two extremes I have allotted the 

 intermediate places as they seemed to me to be merited. 

 The extremes may consequently be said to be based upon 

 actual evidence, the intermediate stages being in some 

 measure impressionist, though I hope not altogether so. 



The similarity of the motor reactions at different emotional 

 periods next requires consideration; it is a possible line of 

 investigation from which something may come. The per- 

 ceptual powers of animals are probably greater than we 

 imagine. We think that we discern similarity in the 

 behaviour arising in wholly different situations, yet some 



