186 A PHILOSOPHER WITH NATURE 



capital of the Corinthian column as a nesting place 

 as familiarly as he probably did to the crevices in 

 the roof of the family cave in primeval times. Even 

 our habit of living in towns does not drive him away, 

 and it is only when his food supply fails that he retires 

 from the London smoke and leaves us alone with 

 the sparrow. 



It may have occurred to others, as it has to me, 

 to question whether some explanation is not to be 

 sought of the curious habit which the swallow so 

 persistently clings to, of building its nest about our 

 houses. There is no reason why we should expect 

 to find the swallow, like the sparrow, in association 

 with man. It is by nature a shy bird ; we do not 

 provide for it in any way, for it subsists on a diet 

 of insects which it hunts abroaol on the wing ; and, 

 above all, it is a migrant, leaving us after a short 

 interval for strange quarters in distant lands. Why 

 is it that such a bird should come and build its nest 

 familiarly round our windows and under our eaves ? 

 I have often wondered whether there may not be 

 some connection between the instincts of the swallow 

 and the rock-dwelling habits of our ancestors the 

 cave-men. Judging by the relics which he has left 

 behind him, primeval man must have occupied, and 

 for enormously long periods, most of the suitable 

 caves within reach in the greater part of the world. 

 The swallow is naturally a cave-frequenting bird ; 

 it builds and breeds in great numbers about the 

 roofs and walls of caves at the present time, and 

 beyond doubt it must often have been the sharer of 

 these rocky shelters of early man. 



The sparrowhawk is a casual visitor to London 

 and the neighbourhood, and like all his kind he is 



