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Feds eye elk contraceptive
Ongoing studies are aimed at finding right role for birth control.
By Rebecca Huntington
Birds do it. Bees do it. But when elk want to do it biologists are stepping in.
Researchers do not want to limit the activity per se, just the results. Biologists are studying the potential of limiting elk populations by using birth control to prevent pregnancy.
In Colorado's Rocky Mountain National Park, biologists are field testing for the first time a shot that prevents pregnancies in cow elk.
"This is purely for research purposes," said Ryan Monello, a natural resource specialist with Rocky Mountain, where elk numbers have grown to 3,000 from 500 in the 1960s. "We just wanted to know if this is even something we should consider."
As research proceeds in Rocky Mountain, wildlife managers at the National Elk Refuge are weighing the pros and cons of birth control in a study that will serve as a blueprint for elk and bison management there and in Grand Teton National Park. A draft is due in November.
Even if proven effective in Rocky Mountain, birth control is controversial. That's especially so among the thousands of hunters who are drawn to the region annually to shoot elk. Some 3,000 elk a year are killed from the 13,000-strong Jackson elk herd in an annual Wyoming rite.
Already hunters are competing with wolves, said Mike Rinehart, president of Elk for Tomorrow, a pro-hunting group that formed in response to the refuge and park study. "Why would we want to implement birth control when the Canadian wolf is doing it for us?" he asked.
Wolves already eat enough elk calves in the greater Yellowstone area to keep elk populations more than under control, he said. Moreover, Grand Teton differs from Rocky Mountain because it has wolves and allows hunting, he said.
"I would be more than happy to donate Wyoming wolves to take down there and help," he said.
However, hunting opponents like the Fund for Animals say birth control should be seriously considered, but representative Andrea Lococo said she has reservations.
The Fund would like to see birth control as only a short-term solution to reduce herd sizes until wildlife numbers can be naturally regulated by predators and the carrying capacity of the habitat, she said.
The Fund is most interested in birth control as a nonlethal method to reduce bison numbers in Grand Teton and on the refuge, she said. And while Rinehart vehemently opposes birth control for elk, he does not oppose its use on bison. Elk for Tomorrow views bison as competing with elk for valuable refuge habitat.
"They can give it to the bison not the elk unless they want to teach wolves how to kill bison," Rinehart said.
Dan Baker, a research biologist with the Colorado Division of Wildlife, is leading the study in Rocky Mountain.
Baker first began testing birth control on captive elk four years ago at the Colorado Division of Wildlife's Foothills research lab in Fort Collins. Those experiments showed the drug administered to cow elk was 100 percent effective in preventing pregnancy, he said. Moreover, Baker monitored the animals' body weight, eating and general health and did not detect negative side effects, he said.
One minor behavioral side effect was that males stayed interested in the inoculated females a few weeks longer than the females that had not received birth control, he said.
"The drug works by preventing ovulation, but it doesn't completely stop estrus behavior," he said.
The side effect is minor and not a concern, he said. But the captive animal environment is "pretty artificial" and field testing is needed to determine the true efficacy of contraceptives, he said.
So last August and September, right before breeding season, biologists and veterinarians captured 34 elk in Rocky Mountain. Seventeen were injected with the contraceptive and the other 17 were treated as controls. Biologists fitted both sets of elk with radio collars to track their movements and behavior.
This spring, biologists will recapture the treated elk to see if they're pregnant.
Atrix Laboratories of Fort Collins makes the contraceptive drug, leuprolide, which is a hormone therapy also used to suppress hormonal secretion in men and women. Biologists inject a biodegradable implant that sits under the elk's skin and dissolves, Baker said.
Biologists are trying to develop a dart gun to deliver the drug from a distance. Today's method of capturing and hand-injecting each animal increases the cost and reduces the effectiveness of the drug, Baker said.
Unlike many state wildlife agencies, the Colorado Division of Wildlife views birth control as a promising tool. State agencies have no incentive to replace hunting with birth control since much of their revenue comes from hunting licenses, Baker said. But the Colorado Division of Wildlife sees contraceptive as a supplement to hunting to control elk populations in urban areas where hunting is not allowed or unsafe, Baker said.
To reassure hunters that birth control is not a replacement, states could adopt policies that restrict the use of birth control to areas where hunting is not an option, such as Rocky Mountain, he said.
"Our agency is being very progressive and trying to deal with the problem of overabundant elk, in this case, in urban areas where hunting is not really feasible or acceptable," Baker said.
The Wyoming Game and Fish Department is less enthusiastic.
"We just don't support any kind of proposal that applies imunocontraceptives to the overall population," said Doug Brimeyer, wildlife biologist with Wyoming Game and Fish.
Birth control is no more natural than hunting. "If we're playing God with elk, we're impacting the natural selection process of those animals," Brimeyer said.
Birth control also could be extremely costly and labor intensive.
"We have questions as to whether or not that's even a valid approach based on the time and amount of effort it would take to administer to an animal each year," Brimeyer said.
Indeed, Rocky Mountain officials estimate the cost of an elk contraceptive program at more than $100,000 per year in Colorado. The cost of a single dose of birth control is estimated at between $100 and $300 per elk.
Despite the drawbacks, federal environmental laws require wildlife managers to consider a range of alternatives on the refuge and in Grand Teton. Birth control is part of that range, said Don DeLong, project manager of the elk and bison study.
For example, birth control could be targeted at hard-to-hunt elk in Grand Teton. Hunting is allowed in the park but only on the east side of the Snake River. So migrating elk often stage on the west side of the river and make a run to the Elk Refuge at night, when hunting is not allowed.
Birth control could be used to reduce the number of elk in Grand Teton where hunter access is limited, DeLong said.
About half the elk on the refuge spend summer in Grand Teton. Wildlife managers are worried that park elk numbers will grow to dominate the refuge winter range. They could crowd herd segments that summer in the Gros Ventre and Teton Wilderness.
The refuge and park study also contemplates birth control for bison. Birth control could help limit bison populations in Grand Teton where bison hunting is not allowed, DeLong said.
Under yet another alternative, birth control is proposed as a substitute for hunting altogether, he said. And the study goes a step further by also looking at permanent sterilization, he said. Those alternatives were developed in response to public comments asking federal managers to consider such options. But researchers said permanent sterilization tends to be less acceptable to the public than birth control, which is reversible.
Population control is not the only application for birth control. Researchers are also studying the potential of contraceptives to control the spread of diseases that afflict elk and bison.
Jack Ryan, a senior researcher for the Animal Plant and Health Inspection Service, has been investigating the possibility of preventing the spread of brucellosis with birth control. Both bison and elk carry brucellosis, a disease that causes females to abort their fetuses.
Bison in Yellowstone National Park are often killed when they leave the park because they may spread brucellosis to cattle. Birth control could be a humane alternative to killing the bison, Ryan said.
Brucellosis is often spread through aborted tissues. If bison do not become pregnant, then they will not shed the bacteria through birthing materials and potentially expose other animals, he said.
As long as the bison test positive for exposure to brucellosis they would be given birth control. But if an animal tested negative for exposure to the disease in later years, it could be allowed to reproduce, he said.
"It's just a nonlethal alternative that doesn't permanently remove an animal from the gene pool," he said.
Likewise, Baker said birth control could play a role in managing chronic wasting disease among elk in Colorado. Reducing the density of animals helps reduce the prevalence of the disease.
Birth control could be combined with hunting to reduce population densities quickly. And birth control could be a substitute for agency killing, which generates a lot of public opposition, he said.
But he added: "It's not the magic formula for controlling animals. It's best used in combination with hunting and culling."
And while research proceeds to see whether birth control is even feasible in the field, Baker said wildlife managers will have to weigh public values in any decisions about whether to use it.
"We have no idea right now how the
public feels about fertility control," he said. "[But]
that should carry a lot of weight as far as what alternatives
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