ARE WE OVER CONTROLLING PREDATORS?

Forest and Bird, Issue 54, 1 November 1939, Page 10

ARE WE OVER CONTROLLING PREDATORS?

(By Richard Pough)

Condensed from Hunting and Fishing” for June.

IT is an old saying that no matter how bad a man is, some good can always be found in him. Can’t the same probably be said for even the most maligned of our native predatory animals? There is always the possibility that if they once had value in nature’s eyes, and legitimate functions to perform, that they may still, at certain times and places, and under certain circumstances, have a value to man. Before we can appraise the full effects of the complete or partial removal of any species of predators from an area, we must understand what role they played in the primitive animal community that existed on it. Another job that predators have to perform is the one of selecting those individual animals that will perpetuate the species. This culling of the weaklings and abnormal individuals from each generation is something predators do quite automatically, because misfits invariably are easier to kill. Among animals, as among humans, certain individuals are always catching diseases of one sort or another, and also some animals, become heavily parisitized by worms, ticks, etc. Among humans these diseased individuals are quarantined temporarily until we can cure them, or permanently if we cannot. In nature’s communities the job of checking the spread of such diseases and parasites falls to the predators. Predators eliminate—because of the ease with which they can be caught animals so sick as to be dangerous potential sources of infection. Not only do they get rid of the sick, but they usually kill off animals that are getting past the prime of life and therefore more likely to serve as a focal point for the start and spread of an epidemic. Thus we see that the functions of predators in a primitive animal community are many, and only insofar as we can take over and perform these functions in their stead are we wise in eliminating them from any area. When domestic grazing animals are completely substituted for wild ones we —although we don’t always— a fair job of carrying out most of these important functions. We control populations to prevent over-grazing

by shipping the annual crop to market, and we carefully select the breeding stock for next year before making such shipments. We isolate and cure or kill diseased and heavily parasitized animals. We invariably include in the market shipments animals that are getting old and past their prime. If an animal dies of some disease we burn or bury it at once. We commonly keep species especially subject to disease, such as turkeys, in small separate flocks, and what game farmer doesn’t know the dangers of not moving the raising ground for young pheasants each year. Finally, we even try, although not too successfully, to combat on behalf of our cattle and sheep their rodent and insect competitors for the life-giving grass. How many of these functions are we in a position to take over on wild areas, where we still seek to perpetuate wild grazing animals? If we interfere with nature’s methods of solving these problems in advance of definite plans as to how we are going to solve them ourselves in the absence of predators, we do so at great risk to the health and stability of the whole animal community of the area. The present condition of deer and elk populations in a number of areas where predators have been largely eliminated, is an indication that in many cases we haven’t even solved the first and simplest of these problemsthe regulation of population levels. The answer to the question of whether predators are to-day being over-controlled on any particular area can best be obtained by inquiring as to whether there are still enough predators left to perform those of their important natural functions that man cannot perform.

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