BKIIAVlorH OF HKSIDFNT MAI I 27 



its wider application; we wish to know the 

 precise sta^e at which the disposition to mate 

 influences the behaviour of the male. Is the 

 female to him, from the moment the seasonal 

 change in his sexual organs takes place, a goal 

 that at all costs must be attained ? Or is it only 

 when the cycle of events which leads up to 

 reproduction is nearing completion that she 

 looms upon his horizon ? One would like to be 

 in a position to answer these questions, but 

 there is nothing in the way of experimental 

 evidence to go upon ; and if I say that there is 

 reason to believe that, in the earlier stages, the 

 female is but a shadow in the external environ- 

 ment of the male, it must be taken merely as 

 an expression of opinion, though based in some 

 measure upon a general observation of the 

 behaviour of various species. 



Before attempting to explain the difference 

 in the times of arrival of the male and female 

 migrant, let us examine the behaviour of some 

 resident species at a corresponding period. 

 My investigations have been made principally 

 amongst the smaller species the Finches and 

 the Buntings which often pass the winter in 

 or near the localities wherein they brought up 

 offspring or were reared. It is true that they 

 wander from one field to another according to 

 the abundance or scarcity of food ; it is also true 

 that, if the weather is of a type which precludes 

 the possibility of finding the necessary food, 

 these wanderings may become extensive or even 

 develop into partial migrations. But under the 



