234 CONSERVATION OF CANADIAN WILD LIFE 



diet to a large extent the years of abundance of many of our 

 important fur-bearing animals is sufficient to warrant a 

 more careful and intensive study of these phenomena and the 

 underlying causes. Is the decrease in abundance due to 

 starvation, owing to the disappearance of the main article 

 of diet, or does a decrease in the food supply affect the fer- 

 tility of the predatory species? According to MacFarlane, 

 the females are said to be more prohfic when the numbers 

 of the animals constituting the main food are on the in- 

 crease. Does the overfeeding consequent upon the great 

 abundance of food affect, in an adverse manner, the repro- 

 ductive powers of the predatory species? All these are 

 problems which demand further close study in the field. 

 It is hoped that such studies, extending over a number 

 of years, may be undertaken by competent investigators 

 in the future, as such a knowledge of the causes of these 

 fluctuations is essential to an adequate understanding of a 

 subject having economic possibilities of a very high order. 



