244 DELIBERATE INTRODUCTION OF NEW ANIMALS 



into direct relationship with man. To-day we could not 

 exist without our introduced domestic creatures, which in 

 number far exceed the original population of large wild 

 animals they have replaced. We who are not farmers 

 would regret the disappearance of the Rabbit from the hill- 

 sides, or of the Pheasant from the coverts ; we who are not 

 foresters would miss the gambollings of the Squirrel, or the 

 solid presence of the Capercaillie in the woodlands. Yet even 

 these mild exotic pleasures are bought at a price. After 

 all, the food supply of a country, so far as most wild creatures 

 are concerned, is almost a fixed quantity, and the total 

 amount of animal life in a country depends upon the quantity 

 of vegetation available throughout the year, for even carni- 

 vorous creatures ultimately depend upon the vegetation 

 which nourishes the herbivores. If then additions are made 

 to the native animal life, by so much as the imports consume 

 is the food of the native stock diminished. Thus arises a 

 struggle between the aboriginal population and the new- 

 comers, a struggle which spreads from food to living spaces 

 and breeding sites, and which is none the less real because 

 in its earlier stages it is almost imperceptible. 



The results of the contest are clear enough in most 

 countries. It may be that the introduction obtains a pre- 

 carious foothold and lives, as it were on the crumbs that fall 

 from the rich native's table, without seriously affecting the 

 creatures into whose environment it has dropped, or that it taps 

 a source of food supply hitherto almostunused, as the Squirrel 

 did in feeding upon the growing shoots of Scottish pine 

 trees. But an unobtrusive existence is the exception, and 

 either the newcomer finds the struggle for food too severe 

 and declines in health and numbers, until it disappears from 

 the fauna it invaded ; or, as often happens, it becomes firmly 

 established, and increasing the difficulties of those old races of 

 residenters upon whose food supply it trenches, causes the 

 weaker of them to languish and to forsake the invaded 

 districts, and finally, driven from one stronghold to another, 

 even to succumb to the new and unaccustomed competition. 



Frequently the introduction of strange animals to a new 

 land has a more immediate and more noticeable effect 

 on the native fauna. For man in transporting creatures for 

 his own purposes often seems to forget that their nature, 



