USDA researchers on trail of coyote control

The predatory behavior of coyotes is largely dependent on whether or not they have offspring. Coyotes without small puppies choose smaller prey, while coyotes with puppies choose larger prey such as lamb and sheep

By Environmental News Network staff

May 15, 2000
Web posted at: 11:06 a.m. EDT (1506 GMT)

Birth control devices may spare coyotes from the bullets of protective farmers, say the authors of a recent study.

Each year, thousands of coyotes are killed to prevent them from preying on livestock, wildlife and even people. Environmentalists campaigning to end such predator control programs may have a less violent solution to managing the coyote population.

Scientists from the U.S. Department of Agriculture are working to produce fragrances that will lure the canine trickster into eating birth-control drugs, according to a report in the May issue of the Journal of Agriculture and Food Chemistry.

"This is the only non-lethal strategy that can be used (in managing) wildlife," said Russ Mason, a biologist at Utah State University.

The researchers tested seven different synthetic attractants on 18 pairs of male and female coyotes and recorded their behavior.

"In general, females tended to interact more frequently with the attractants than males," said Bruce Kimball, a chemist with the USDA's National Wildlife Research Center.

"Each of the attractants has its own benefit," Kimball said. For example, one of the fragrances caused the coyotes to bite, which may be key to the oral method of the birth control.

Chemical attractants have long been used to lure coyotes into traps. Because of the animal's sharp sense of smell, the fragrances are often derived from blood, urine and other animal fluids. However, due to the variability of these substances, the fragrances have not always worked their magic, the researchers said.

"Coyote management requires more specialized attractants," Kimball said.

Coyote pups may be a rarer occurrence if new birth control methods succeed

The purpose of reducing coyote births is not to control their population but rather to control their feeding habits. The predatory behavior of coyotes is largely dependent on whether or not they have offspring, explained Mason. "Coyotes without small puppies choose smaller prey, while coyotes with puppies have a larger need to provide energy for their offspring and choose larger prey like lamb and sheep," he said.

While scientists have not determined exactly the population of coyotes in the United States, they do know that the animal's range has expanded significantly. With a population in nearly every state, coyotes are migrating to many urban areas.

The sheep population in the United States has declined more than 25 percent in the past decade. Coyote attacks are the major cause of this decline, according to a USDA study.

The birth control method could also be used in wildlife recovery programs, Mason added. Coyotes are a major predator of endangered pronghorn sheep, he said.

The approach has won favor with most environmental groups.

"Any time a non-lethal technique can be used it should be favored," said Bob Ferris, vice president of species conservation at Defenders of Wildlife. "This technique has a lot of promise."

Copyright 1999, Environmental News Network, All Rights Reserved

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U.S. Department of Agriculture
Journal of Agriculture and Food Chemistry
Defenders of Wildlife
Coyotes

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