File:The conservation of the wild life of Canada (1921) (14752498141).jpg

Identifier: conservationofwi01hewi (find matches)
Title: The conservation of the wild life of Canada
Year: 1921 (1920s)
Authors: Hewitt, Charles Gordon, 1885-1920
Subjects: Game protection Birds Game and game-birds
Publisher: New York, C. Scribner's Sons
Contributing Library: The Library of Congress
Digitizing Sponsor: Sloan Foundation

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groups. First, the herbivorous rodents such as miceand rabbits, which are very prolific and increase in numbersuntil they reach an abundance which causes overcrowding,when an epidemic of disease almost wipes them out andtheir numbers rapidly decrease to a minimum. Second,we have the nimierous predatory animals which depend fortheir subsistence either directly or indirectly upon the miceand rabbits. These animals exhibit fairly regular periodicfluctuations in numbers, their abundance being correlatedwith the abundance of the animals upon which they feed,although, as we pointed out in the case of the fisher, theremay be a distinct periodic fluctuation which does not appearto be directly related to the fluctuation in the numbers ofany particular food animal. Finally, we have the animalsthat feed on a mixed or exclusive diet of insects, vegetableproducts, fish, or miscellaneous diet, that do not show anymarked periodic fluctuations. The economic value of this study in enabling us to pre-
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PERIODIC FLUCTUATIONS OF BLACK BEAR, RACCOON, AND BEAVER 234 CONSERVATION OF CANADIAN WILD LIFE diet to a large extent the years of abundance of many of ourimportant fur-bearing animals is sufficient to warrant amore careful and intensive study of these phenomena and theunderljdng causes. Is the decrease in abundance due tostarvation, owing to the disappearance of the main articleof diet, or does a decrease in the food supply affect the fer-tihty of the predatory species? According to MacFarlane,the females are said to be more prohfic when the numbersof the animals constituting the main food are on the in-crease. Does the overfeeding consequent upon the greatabundance of food affect, in an adverse manner, the repro-ductive powers of the predatory sjDecies? All these areproblems which demand further close study in the field.It is hoped that such studies, extending over a numberof years, may be undertaken by competent investigatorsin the future, as such a knowledge of the causes of thes

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