188 TERRITORY AND REPRODUCTION 



Warblers, Whinchats, Stonechats, Meadow- 

 Pipits, Tree-Pipits, and Skylarks. Suppose 

 then that there had been sixteen pairs of Yellow 

 Buntings instead of eight ; that there had been 

 other pairs, which assuredly there were, inhabit- 

 ing the locality ; that they had also resorted, 

 which assuredly they did, to the coppice and 

 arable ground for the purpose of securing food ; 

 and that their numbers had also been increased 

 in a similar ratio would a supply of food for 

 all have been forthcoming with the necessary 

 regularity and promptitude ? Well, the parents 

 might have had to travel a little farther ; but 

 even if they had been compelled to do so, their 

 absence would only have been prolonged by so 

 many minutes the more, and under normal 

 conditions what harmful result to the offspring 

 could possibly have followed ? The question for 

 us, however, is not what might have occurred 

 under normal conditions, but whether the life 

 behaviour is so adjusted as to meet the exigencies 

 of diverse, and in this case of abnormal, circum- 

 stances. Now the capacity of the young to 

 resist exposure diminishes very rapidly when the 

 temperature falls below the normal the danger 

 zone seems to be reached at approximately 

 52 F., and the length of time during which they 

 survive then becomes astonishingly short and 

 moreover the fall in the temperature would tend 

 to decrease the supply of insect life upon which 

 they depend, so that if the size of the territories 

 had been reduced by one half, and the parents 

 in consequence had been compelled to seek their 





