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natural predators does little good
-Dave Rice, Reno Gazette Journal February 9, 2007
"And to the conservation biologist, it is an embarrassing contradiction between science and practice."
That's the opinion of wildlife managers regarding the killing of 100,000 native U.S. predators each year by the Wildlife Services branch of U.S. Department of Agriculture, according to William Stolzenburg, a freelance journalist.
"Topping the casualties are some 70,000 coyotes," he said in a recent article.
Given to me by my friend and former wildlife manager, Fred Wright, the article was the feature article, "US or THEM," in the Oct.-Dec. 2006 edition of the magazine "Conservation In Practice," published by the Society for Conservation Biology. In the article, Stolzenburg takes a fresh look at why predators not only continue to be killed in America, but why the archaic practice seems to be gaining more of a following in recent times, despite scientific studies that conclude that it is unnecessary and does little good.
At the heart of Wildlife Service's work on predator control is a $10 million budget mainly used on its coyote control program, which kills approximately 75,000 of the wild dogs to reduce predation on domestic sheep in the western U.S. Stolzenburg cites a study conducted 10 years ago by Kim Berger, then a master's student at the University of Nevada, Reno, that the significant decrease of the domestic sheep in the west (85 percent since the 1940s) was not due to coyote predation, as often claimed by sheepmen, but was mainly due to economic reasons.
"It turns out the biggest culprit by far to explain the missing sheep is the high price of hay. Wages and lamb prices are important players, too," Stolzenburg wrote in his article. "Even the rancher's age has more to do with his predicament than do predators. At the statistical bottom of Berger's list of prime suspects sits the coyote."
Stolzenburg concedes that certain predators in certain situations can make life miserable for those struggling to make an honest living raising what he refers to as easy prey.
"Whereas modern biologists would often recommend surgical tweezers in that regard, the nostalgic tool of choice for those in charge remains the sledge hammer: kill enough coyotes -- or bears or wolves or cougars, goes the thinking -- and the problem will be solved."
That same line of flawed reasoning exists here in our state also. For many years, a small but tenacious and vocal group of Nevada hunters have attended Wildlife Commission meetings and encouraged commissioners to do something about predators, mainly mountain lions, in the state that they claim were killing vast numbers of deer each year, and to a lesser extent, bighorn sheep. Deer numbers have been down for more than a decade and the reasoning of those who blame mountain lions is simple: kill mountain lions and the deer herds will return. Some individuals even contend -- and apparently believe since they are quick to repeat their theory -- that every mountain lion in the state kills a deer a week.
Using a figure of 3,000 lions statewide, a reasonable figure according to NDOW, the annual predation level by lions reaches 150,000 deer per year, which would roughly double the state's population of this species in a good year. The problem with the outlandish theory is that each mountain lion does not kill a deer a week.
Another interesting point made by Stolzenburg was a finding made by three scientists at California's Hopland Research and Extension Center. The key and consistent point coming out of Hopland was that not all coyotes kill sheep, according to study results. The Hopland researchers learned through 14 years of radio tracking and DNA testing that nearly every sheep killed by a coyote is killed by an alpha coyote. Since alpha coyotes are the savviest and most suspicious of the clan, they are the most difficult to catch.
The conclusion of the Hopland group was, "...that randomly slaughtering a bunch of coyotes to protect a flock of sheep was as effective as killing no coyotes at all," according to Stolzenburg.
A very interesting point made by Stolzenburg in his article is that when predator populations are significantly reduced, populations of their prey grow unchecked and often negatively affect their habitat and the habitat of other species. He cites many examples from white tailed deer numbers in the east growing beyond their carrying capacity because of the lack of predation, to the fall of kelp forests where sea otter numbers were insufficient to keep kelp-eating sea urchins in balance.
Another intriguing example is the re-establishment of gray wolves in Yellowstone National Park.
"For the last decade, packs of gray wolves have run loose in Yellowstone National Park," Stolzenburg wrote. "Their presence has apparently transformed the land's living fabric. For the previous 70 years, willows had been chewed to stubs by the world's largest herd of elk. Now, with wolves patrolling the stream valleys, willows have suddenly and conspicuously sprouted into thickets two meters tall."
The growth of the willows has been good for other types of wildlife including beavers, songbirds, salamanders, trout and muskrat. In addition, the numerous elk carcasses have become important to scavengers; 12 species in all.
Early Nevada newspapers often reported in the late 1800s of rancher and farmer problems with what they felt were an overabundance of predators that they tied to losses of cattle, sheep and other domestic animals. Shortly after significant and apparently successful programs to kill these predators, these same farmers and ranchers were besieged with huge numbers of herbivores including rabbits, squirrels, gophers, marmots, and other plant eaters that attacked and ruined their crops. There were few if any predators left to keep these populations in check.
Stolzenburg concludes that fear and aggression in humans are offset, at least in part, by curiosity and reverence towards animals.
"Long ago these were traits that helped the human animal learn the art of survival, if not the grace of sportsmanship, from its most dangerous competitors," he wrote.
"And so these traits remain, manifested as the inner magnets that bring world travelers to Serengeti lion safaris and throngs of wolf-watchers to Yellowstone's Lamar Valley. Therein may be reason to believe the human capacity to live with predators may one day overhaul its overwrought habit of killing them."