POISONOUS necklaces for sheep, designed to kill predatory coyotes, are a growing hazard for eagles and other endangered species, claim conservationists. The warning comes as the US Environmental Protection Agency (EPA) is moving towards approving the collars for use in Oregon. Five other states are waiting behind Oregon in the queue for approval.
The collars, which contain a notorious poison called compound 1080, have already been sanctioned for use in Montana, New Mexico, South Dakota, Texas and Wyoming. But until now, the paperwork allowing individual ranchers to use the collars has been completed 鈥渁t a glacial rate鈥�, says Bill Jacobs, a biologist with the EPA in Washington DC.
This seems about to change. 鈥淭here was a lot of opposition to this poison, but with pressure from the ranchers and the agriculture department, the wave is coming back the other way,鈥� says Tom Skeele, director of Predator Project, a conservation group based in Montana. If the applications by California, Idaho, Ohio, Oregon, Utah and Virginia are all approved, he says, the number of collars in use could double in less than a year.
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The necklace consists of two rubber bladders each filled with ten times the lethal dose for a coyote of compound 1080, or sodium fluoroacetate. The collars are placed around the necks of a few sacrificial lambs in a flock that has been attacked. The coyotes prefer defenceless lambs and usually go for the throat of their prey, so they stand a good chance of puncturing the reservoirs. Studies carried out by the US Department of Agriculture (USDA) show that the reservoirs deliver a fatal dose in about three-quarters of attacks.
Compound 1080 has a long, controversial history. The poison kills slowly and painfully over many hours. It was widely used in the 1960s at 鈥渂ait stations鈥�, where hunks of fresh meat were injected with the poison and left out for coyotes. In 1968, the US had 16 000 bait stations in place.
Unfortunately, the bait stations also killed other species. The EPA banned the use of compound 1080 for predator control in 1972 after the deaths of endangered animals, including eagles and a California condor. But after years of research, the EPA approved the livestock protection collars laced with compound 1080 in 1985. Government researchers claim the collars should only target animals that attack livestock.
Critics say the collars pose a serious risk of secondhand poisoning, as other species will scavenge the coyotes鈥� carcasses. 鈥淭he coyotes take off and run for miles before they die,鈥� says Skeele. 鈥淭here鈥檚 no way to monitor how many animals get a dose of that poison.鈥� In an attempt to stop the collars being used in Oregon, Predator Project has organised a letter-writing campaign, targeting local EPA officials.
Both the EPA and the USDA reject Predator Project鈥檚 claims. Guy Connolly, a biologist with the USDA in Denver, Colorado, argues that his research shows that most animals which might scavenge a poisoned coyote are unlikely even to become ill. A more realistic threat, he says, is the possibility of other animals feeding on a contaminated sheep carcass before it is discovered and removed. 鈥淭he risk is there and we can鈥檛 deny it,鈥� says Connolly. 鈥淏ut it鈥檚 low enough that it isn鈥檛 a good reason not to use the collar.鈥�
In one study, dogs were given the contaminated neck and head of dead sheep to feed on for a week. 鈥淭wo dogs died, but three did not,鈥� says Connolly. In the wild, Connolly argues that contaminated carcasses would represent less of a threat.