Doggone: Prairie Dogs Face a New and Deadly Threat
Prairie dogs have been eliminated from more than 95 percent of their grassland habitat. And now they, and the vast and complicated ecosystems they sustain, face a new and deadly threat.
The irrational hatred of prairie dogs is particularly evident in the "varminters," who speak reverently of "IVG" (instant visual gratification), experienced when their high-powered bullets make prairie dogs explode in "red mist." "Red-Mist Society" T-shirts were popular in 1992 when, on another Audubon assignment, I observed a prairie dog shoot in South Dakota, where a bill was later introduced to rename the prairie dog the "prairie rat." Rich Grable--better known as "Mr. Dog"--rested his .222 rifle on a foam pad taped to the base of his truck window and partly melted by barrel heat. Crack. He cut a target in half, sending hindquarters spinning. "Dead," he declared, punching his dashboard-mounted kill counter. Babies, standing beside burrows with paws on their siblings' shoulders, exploded in red mist. Once Grable killed five with a single shot. "Can ya hear it go plop?" he cackled. "Dissolved him! Ha. Ha." Whenever a target dragged itself back into its burrow, minus major body parts, Mr. Dog would shout: "I done somethin' to him." According to his shooting journal, he'd killed 7,652 the previous year.
That mindset hadn't changed on August 18, 2009, when I visited Gene Bertrand at his cattle ranch in Wallace, Kansas. Bertrand spoke proudly of the wild turkeys I'd seen behind his house, and he told me about all the species that depend on prairie dogs and how some of them are disappearing. But even prairie dog advocates aren't opposed to hosting varminters at $150 per person, per day. "We had a nice hunting business up until a year ago," he said. "We averaged $25,000 a year; that's about what I get per acre with cattle. We used to see 30 or 40 ferruginous hawks a day; they learned to come to the sound of the guns."
That wasn't great for the hawks because the prairie dogs varminters leave to rot on the ground are frequently impregnated with lead splinters, poisoning anything that eats them. For four years Ron Klataske, director of Audubon of Kansas, has been offering varminters nontoxic copper ammo at the cost of slightly cheaper lead bullets. He's had no takers.
Shooters can only thin dog towns, not eliminate them. But a weapon of mass destruction has recently been deployed on prairie dogs. It's Rozol, an anticoagulant that causes uncontrolled bleeding in anything that ingests it. Rozol was registered for black-tailed prairie dogs by George W. Bush's EPA in Colorado, Kansas, Nebraska, Oklahoma, Texas, and Wyoming and, in May 2009, by Barack Obama's EPA in the remaining five states where black-tailed prairie dogs exist--Arizona, Montana, New Mexico, South Dakota, and North Dakota. (A similar anticoagulant, Kaput, has also been registered in Colorado, Nebraska, Wyoming, Texas, and Kansas, but it's not in wide use, perhaps because it's newer.) Three Ph.D. scientists from the EPA's Environmental Fate and Effects Division were ignored when they warned their superiors that Rozol has "considerable potential for both primary and secondary risks to birds and nontarget mammals and possibly reptiles." (As Audubon went to press, Defenders of Wildlife and Audubon of Kansas sued the EPA over its decision about the use of Rozol on prairie dogs.)
Zinc phosphide, the previous poison of choice, kills few nontarget species. It's effective, fast-acting, cheap, and readily available. But prairie dogs find it bitter, so to condition them to eating, you have to "pre-bait" with untreated grain. The advantage of Rozol is that prairie dogs don't mind the taste, so you can skip pre-baiting. According to the label, you must place Rozol-treated bait only in burrows, which isn't always done. And you must return and bury the carcasses, something few if any ranchers would do and which is impossible anyway because Rozol can take up to 20 days to kill, during which time prairie dogs leave their burrows, slowly bleed from every orifice, and stumble around, magnets for all predators and scavengers.
Ferruginous hawks, golden eagles, bald eagles, owls, magpies, turkey vultures, badgers, swift foxes, coyotes, raccoons, and grain eaters like wild turkeys and red-winged blackbirds have been turning up dead around Rozol treatment sites, and while some carcasses have yet to be tested, lethal concentrations of Rozol are being found in ones that have been.
The Fish and Wildlife Service is outraged. Pete Gober, the biologist in charge of black-footed ferret recovery, says this: "For every dead animal you find on the ground there might be 100 you don't find because nature cleans them up so quickly. We've hammered EPA with our concerns about Rozol and about permitting it without ever consulting us on endangered species impacts [as required by Section 7 of the Endangered Species Act until the George W. Bush administration changed the rule, possibly illegally]. And EPA just blows us off."
On August 19, 2008, the Western Association of Fish and Wildlife Agencies (WAFWA), representing 23 states and Canadian provinces from Alaska to Texas and Saskatchewan to Hawaii, wrote the EPA's director of pesticide programs, Debbie Edwards, urging her to fully consult about Rozol as required by law and, meanwhile, to rescind all existing permits because of the gross secondary poisoning potential. WAFWA never received a response. So on March 24, 2009, Bill Van Pelt, WAFWA's grasslands coordinator, wrote John Herbert, head of the EPA's Insecticide-Rodenticide Branch, documenting secondary poisoning of birds. And he attached the unanswered August 19, 2008, letter to Edwards. Van Pelt never received a response. Then, last May 13, Herbert signed the expanded Rozol permit.