THE NATURAL ENEMIES OF GAME BIRDS 



]\Iany people have mistaken ideas regarding the general effect of 

 predacious animals on wild game. It is true that certain hawks and 

 predatory mammals prey extensively upon game, but that they con- 

 stitute the most important or critical factor in reducing the numbers 

 of individuals of game species we believe to be untrue. We need but 

 point to conditions as they exist in the wild to prove that this idea is 

 erroneous. Where game is abundant predacious birds and mammals 

 are also abundant; where game is scarce (due probably to a lack of 

 food) predacious birds and mammals are also scarce. In other words, 

 the number of predacious animals is controlled by the supply of game. 

 It can be seen, therefore, that a certain balance exists between wild 

 game and its enemies. Forbush (1912, p. 541) says: "It is the mis- 

 sion of the native natural enemies to help preserve birds, to keep 

 them up to full efficiency and at the same time to prevent their 

 increase in numbers beyond the limit of safety. 



Predacious birds and mammals are to be looked upon as constitut- 

 ing but one of many factors which affect the numbers of game birds 

 and mammals, and care should always be taken that the importance 

 of this factor be not overemphasized. No attempt is being made here 

 to underestimate the actual damage to game caused by any of its 

 enemies, but rather to point out that there is a tendency among many 

 people at the present time to interpret wrongly the relative importance 

 of the different categories of enemies. 



However, at times and under more or less artificial conditions, 

 control of enemies may be advantageous to game birds. Destruction 

 of predacious animals is of value when they have become abnormally 

 abundant due to a destruction of ^/(etV enemies, or to th«ir taking 

 advantage of the increased food supply furnished by cultivated crops. 

 The crow in the eastern United States is a case in point. In Africa, 

 where numerous game refuges have been established in the Transvaal, 

 it has been found that the systematic destruction of certain predacious 

 birds and mammals has been distinctly beneficial in increasing game. 



Destruction of mountain lions here in California has tended to 

 eliminate one of the chief factors in the decrease of deer and hence 

 increased the supply of the latter animals for the use of man. But 

 in most attempts at control, many really, though indirectly, beneficial 

 animals are destroyed, while some of the worst enemies of game go 

 free. The reason for this is that in but few instances can friend and 

 foe be so easily distinguished as in the case of the mountain lion. It 

 is very easy to jump to a conclusion in regard to the effect of any 



[19] 



