Nonlethal Deterrents for Coyotes

By Ron Daines

March/April 2005 -- With a public increasingly sensitive about methods of eliminating predatory animals, tools like poisons and lethal traps are being phased out.

Now, there is a novel idea that may overcome such concerns: death by chocolate.

Chocolate has long been known as lethal to dogs, so scientists at the U.S. Wildlife Service's National Wildlife Research Center are working to refine chocolate's dosage levels and customize a delivery method for coyotes.

"We're looking at methods that satisfy public concern over humane killing, the idea being that killing coyotes with something that doesn't kill humans may be seen as more humane," said John Shivik, supervisory research biologist at the Logan, Utah, research facility.

Chocolate is but one of several nonlethal approaches the researchers are exploring.

Shivik and his associates are using high-tech GPS collars to track killer coyotes and learn more about their behavior, which might offer better insights into humane management. As the research matures, they'll assess coyote response to stimuli such as guard animals, traps, people and aircraft.

"We're trying to understand coyote movements, find new toxicants in light of lost controls, develop repellants and design new capture tools," he said.

Shivik discussed several tools under study:

• noise-generating devices have been found to work for short periods, but the animals typically habituate to the sounds;
• flashing lights coupled with sirens can reduce sheep loss to some extent, especially in smaller pens or bedding grounds, but again the animals may become used to the devices. Plus, such devices can annoy humans; and
• a technique, used in ancient Eastern Europe, in which flags are draped along ropes to drive animals into captivity. The flag-line ropes require maintenance, However, limiting their use to smaller fenced areas.

Other potential nonlethal deterrents are chemical repellents, biological odor repellents, disruptive harassment, conditioned taste aversion, electronic training collars and inhibition of reproduction.

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