196 BIRD HAUNTS AND NATURE MEMORIES 



for the phytophagous, but for the carnivorous forms ; a 

 good year, an increased output of cultivation, the intro- 

 duction of a new or alien crop, is followed by an increase 

 of vegetable feeders, an increase of their natural enemies, 

 and of the creatures which subsist upon them. What is 

 the result ? The numbers are raised above the normal, 

 and when the normal food supply returns, famine follows 

 as surely as when the supply was short; there are too 

 many mouths to be filled. Thus, taking an average of 

 years, the necessary average is maintained, and this is 

 nature's balance. 



It is fair to say that there cannot be in any civilised, 

 indeed in any, country populated by man a real natural 

 balance; man is the great disturber of nature. But in a 

 country like Britain, where civilisation has been working 

 for the ends of man for ages, there is what we may call 

 a human or artificial natural balance; a point at which, 

 under the present artificial system, the interrelation of 

 plants and animals, cultivated and domestic as well as 

 wild, remains more or less constant. It is our duty to 

 maintain that present-day balance so far as we can con- 

 sistently with our actual requirements, for if we fail 

 mankind as well as the lower animals will suffer. It is 

 with this end that economic zoology and botany should be 

 studied. 



The increase beyond the normal proportions of any 

 species of bird, due to protection which has not taken into 

 consideration consequences, may be a tragedy. It may, 

 probably will, affect our life interests; it certainly will 

 have influence upon the relative numbers of other forms. 

 Need I mention as problems of the day the extraordinary 

 increase since 1880 of the black-headed gull and the 

 starling, two species wholly valuable in their proper 

 proportions, but threatening other forms, actively or 

 passively, now that they have become so numerous. 



