82 



Flashlights on Nature 



and ill another, close l"»y, tliey will be very un- 

 connnon or cjuite unknown. It is probable that 

 this relative tietjnency or scarcity depends upon 

 the distribution ol' their proper food-insects. In- 

 deed, just as we all know that an " army fights 

 upon its stomach," so we are bej^inninj^ to know 

 now that commissariat lies at the bottom of most 

 problems of animal life. I used to wonder on the 

 Riviera why trap-door spiders, with their lon^ 

 tubular lusts, were abundant in certain deep red 

 clay-banks, but wholly wanting in others, just as 

 sunny, just as soft, just as easy to tumiel ; till (jue 

 day it struck me that the spiderless banks were ex- 

 posed now and then to the cold wind, the niistro/, 

 and hence were naturally almost tlyless. As a 

 matter of C{)mse, the spiders went where the flies 

 were to be fouiul ; and these open banks, thouj^h 

 suimy and warm, were from the spider's point of 

 view mere Klondykes or Saharas. 



It is just the same with the butcher-birds. 

 Beetles and bees freipient for the most part 

 warm, crumbling soils ; they are infrequent on 

 damp clays and chilly, marshy places. Sandstone 

 and chalk attract them ; on London cla\ or the 

 damp Hats of the Weald they are few and far be- 

 tween. Hence, where the beetles are, there will 

 the shrikes be j^athered to^^ether. They abound 

 (comparatively) in warm sandstone hills, but are 

 almost unknown in chilly clay districts. Not that 

 they mind the colcl as such ; it is the question of 

 food that really affects them. So, too, with the 

 swallows and othei lon^-winj^ed insect-hawkers. 



