Wildlife Damage Management, Internet Center for


Date of this Version

September 1966


As you can see from the general tenor of the printed program for this seminar, I am in the unenviable position of trying to discourage you from certain types of chemical control; but my assigned topic "Side Effects of Persistent Toxicants," implies that mission. However, my remarks may be somewhat anticlimax at this time, because it is now generally conceded that we need to reevaluate certain chemicals in control work and to restrict or severely curtail use of those that per¬sist for long periods in the environment. So let me detail my reasons for a somewhat negative attitude toward the use of the persistent hydrocarbons from my experience with the effects of these materials on birds. But first a few words of caution about control work in general, which so often disrupts natural processes and leads to new and unforseen difficulties. As an example, I think of the irruption of mice in the Klamath valley in northern California and southern Oregon in the late '50's. Intensive predator control, particularly of coyotes, but also of hawks and owls, was followed by a severe outbreak of mice in the spring of 1958. To combat the plague of mice, poisoned bait (1080 and zinc phosphide) was widely distributed in an area used by 500,000 waterfowl each spring. More than 3,000 geese were poisoned, so driv¬ing parties were organized to keep the geese off the treated fields. Here it seems conceivable that the whole chain of costly events--cost of the original and probably unnecessary predator control, economic loss to crops from the mouse outbreak, another poisoning campaign to combat the mice, loss of valuable waterfowl resources, and man-hours involved in flushing geese from the fields--might have been averted by a policy of not interfering with the original predator-prey relationship. This points to a dilemma we always face. (We create deplorable situations by clumsy interference with natural processes, then seek artificial cures to correct our mistakes.) For example, we spend millions of dollars in seeking cures for cancer, but do little or nothing about restricting the use of known or suspected carcinogens such as nicotine and DDT.