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The elk of Rocky Mountain National Park are wildlife’s couch potatoes. Rather than roam widely throughout the 415-square-mile park and the land outside it, they are content to laze around in meadows, eating, sleeping and mating. With no predators, they can afford to be slackers. Many of them saunter into the tourist town of Estes Park outside the eastern entrance. There, they mosey along city streets and loiter on golf courses. Their inertia has created problems in the park, however. Aspen and willow stands are denuded where the elk do much of their grazing. That habitat is vital to a variety of birds and butterflies, park officials say. The damage has also driven out most of the beavers that once populated the area, which in turn has caused a nearly 70-percent decline in surface water that helps nourish the very habitat being damaged. After years of debate, Rocky Mountain National Park decided on a solution: Kill a portion of the voracious ungulates. It’s not an image coveted by the National Park Service – sharpshooters picking off the park’s most iconic creatures. The killing is done at dawn in winter with rifles equipped with sound suppressors.

Shooting Vs. Birth Control to Keep Elk in Check at Rocky Mountain National Park

The elk of Rocky Mountain National Park are wildlife’s couch potatoes. Rather than roam widely throughout the 415-square-mile park and the land outside it, they are content to laze around in meadows, eating, sleeping and mating.

With no predators, they can afford to be slackers. Many of them saunter into the tourist town of Estes Park outside the eastern entrance. There, they mosey along city streets and loiter on golf courses.

Their inertia has created problems in the park, however. Aspen and willow stands are denuded where the elk do much of their grazing. That habitat is vital to a variety of birds and butterflies, park officials say. The damage has also driven out most of the beavers that once populated the area, which in turn has caused a nearly 70-percent decline in surface water that helps nourish the very habitat being damaged.

After years of debate, Rocky Mountain National Park decided on a solution: Kill a portion of the voracious ungulates. It’s not an image coveted by the National Park Service – sharpshooters picking off the park’s most iconic creatures. The killing is done at dawn in winter with rifles equipped with sound suppressors.

There is, however, a nonlethal method that can potentially keep the elk in check and lessen the need to kill them: Birth control. In January, a team of researchers wrapped up a three-year field study in which dozens of cow elk were injected with a vaccine called GonaCon designed to prevent pregnancies. The vaccine worked well for up to two years. But is wildlife contraception a viable tool in controlling proliferating wildlife herds? If it is, it might also be one means of managing the size of rapidly-breeding wild horses in the West and nettlesome bison at Yellowstone National Park.

“I’m always very wary when we try to do Mother Nature’s job better than she does,” says Jenny Powers, a National Park Service wildlife veterinarian and one of three lead scientists who participated in the elk research.

But Stephanie Boyles, a wildlife scientist with the Humane Society of the United States, welcomes the prospect of family planning for elk. “As stewards, we are called on to do something to keep (wildlife) in balance with nature,” she says. “It’s a politically contentious area.”

***

Elk are native to the Rocky Mountain National Park area, but unregulated hunting wiped them out by the 1870s. Their only significant predators were wolves, and they were eradicated by 1900. Elk were reintroduced in 1913 and 1914, and the national park was established in 1915. Congress banned hunting within the park in 1929. The elk population quickly grew – so much that the animals decimated parts of the park’s vegetation. Between 1944 and 1969 park rangers culled some of the elk to keep their numbers more manageable. (Culling differs from hunting in that it’s not recreational and there’s no element of a fair chase.)

In 1969 the park began a “natural regulation policy” in the belief that hunting of elk outside the park would control their numbers inside it. That didn’t happen, in part because the park’s herd is less migratory and more concentrated than under natural conditions. Many of the elk spend winters in the eastern part of the park, where their munching has damaged some aspens to the point where they don’t grow back.

Park officials say the optimum population within the park is between 600 and 800. Between 1997 and 2001, the park estimates there were between 2,800 and 3,500 elk within the boundaries. There also are another 1,000 to 1,300 elk that winter outside the park.

The park began a $6-million, 20-year plan in 2008 to reduce the elk population and restore the plant life it damaged and destroyed. The plan calls for “gradual lethal reduction” and fencing around some of the most badly-damaged aspens and willows, while leaving open the options of fertility control and wolves.

Four alternatives were considered, including one that would have culled far greater numbers of elk in the park, and another that would have phased in a maximum of 14 gray wolves. The thinking was that the wolves would kill some of the elk and scare others into dispersing elsewhere in the park. Their grazing would then be over a wider area and be less destructive. Yet another alternative would have been the use of “fertility control agents,” but even doing this would have still required some culling to keep the elk’s numbers at an acceptable level.

Elk have now been culled inside the park three years in a row. Park service personnel and others, including 23 trained volunteers who get $7 a day to cull the elk, do the job. Some 122 females and one male that had the bad luck to be mistaken for a female have been killed in the past three years. (Seventy-nine of them of them were euthanized during the contraception research, while the remaining 44 were culled, according to Kyle Patterson, the park’s spokeswoman.)

That’s far less than the maximum of 200 animals a year that park officials had said might have to be culled. Patterson cites a couple of reasons. A historic snowstorm in 2003 caused many of the elk to migrate out of the park toward the city of Loveland 30 miles to the east. And there was a record hunting harvest outside the park in 2006. All of that can be reversed with a series of mild winters or if the Loveland vagabonds return.

***

GonaCon was developed in the early 1990s by Lowell Miller and other scientists at the National Wildlife Research Center, the research arm of the United States Department of Agriculture’s Animal and Plant Health Inspection Service in Fort Collins, Colo. Sitting on 43 acres in the foothills, the center’s mission is to mitigate human-wildlife conflicts, whether by nonlethal or lethal means. Its work includes conducting research into reducing bird and aircraft collisions, developing nonlethal ways of lessening wildlife damage to forests and analyzing toxic concoctions aimed at killing tiny, nonnative coqui frogs in Hawaii.

GonaCon is registered by the U.S. Environmental Protection Agency for use on female white-tailed deer. The vaccine has also been tested on other animals, including Yellowstone bison, feral cats and dogs and California ground squirrels. Federal scientists also partnered with a private company on an oral contraception for use on urban Canada goose and feral pigeon populations, and are working on an oral contraceptive for feral hogs.

GonaCon works by stimulating the production of antibodies that reduce the ability of a hormone called GnRH to trigger the release of sex hormones. Females don’t go into heat and males aren’t amorous as long as there are sufficient levels of antibodies in the female’s body.

The Rocky Mountain National Park elk were vaccinated in the daunting cold of January 2008. First, the animals had to be shot with a tranquilizer dart – not easy on mornings when the drug froze inside the dart. The dart guns are accurate up to 45 meters, says Powers, the park service veterinarian. “The habituation of these animals and their fearlessness of humans made this possible,” Powers says. “There are very few (elk) populations close enough to dart them with a tranquilizer.”

Once sedated, the elk were rolled on to their chests so they could breathe easier, blindfolded, injected with the vaccine and fitted with a radio telemetry collar to locate them later. Samples of blood, feces and hair were extracted. Then they were injected with another drug to reverse the effects of the tranquilizer. The entire process took about 40 minutes, Powers says.

None of the critters died while being treated or examined, but one did give researchers a surprise when she got to her feet. Normally, elk bolt in the direction away from the scientists when they come to. “But this animal seemed disoriented and chased my colleague around and around the willow,” Powers says.

***

Elk that were subsequently recaptured were checked not only for pregnancy but chronic wasting disease, a transmissible, untreatable and fatal neurological disorder also found in deer. Hunters outside the park were asked not to shoot at elk wearing collars, and animals treated with GonaCon wore tags advising hunters not to consume their meat since the vaccine may not have cleared their bodies.

One year after injecting 60 Rocky Mountain National Park elk with GonaCon, 10 of the animals were recaptured. None was pregnant. Yet 90 percent of the control group recaptured – also composed of 60 females given a saline solution — were pregnant.

Powers declined to provide data for the animals recaptured after the second and third years until she and her colleagues publish the results in a scientific journal. But she says the vaccine, while still effective after the second year, was less so than after year one. And after three years, the percentage of pregnancies was greater than after two years. (In a small study of captive elk between 2004 and 2007, females injected with GonaCon actually were more infertile with each passing year. The percentages were 86, 90 and 100 percent in one group, and 90, 100 and 100 percent in a second group given a stronger dose of vaccine).

Powers thinks GonaCon might be effective in free-roaming elk for a year or two, but she’s equivocal about its potential. Some animals that have been treated may leave the park and never return, while others living outside the park – like the Loveland emigrants — may return, she says. Those sorts of variables dilute GonaCon’s effectiveness. She also points out that determining how much impact a contraceptive has on reducing a herd’s numbers is imprecise because severe weather and deaths from chronic wasting disease kill an undetermined number every year.

She’s not alone in her guardedness. “It’s just a bit too early to tell where we’re going to go next,” says John Mack, the park’s branch chief of natural resources. “We need to wait and be patient.”

Every one of the elk in the GonaCon study had an abscess at the injection site, Powers says. The researchers found nothing to suggest that the sore spots became infected, hindered them in foraging or made them lame. Nor were they aware of behavioral changes caused by the vaccine. Since they didn’t monitor the elk year-round, they just don’t know. “Free-ranging wild behavior with GonaCon has not been answered,” Powers says.

Still, there is reason to believe that wildlife contraception may become a more common method for controlling wildlife populations. Another contraceptive, Porcine Zona Pellucida or PZP, has been field-tested for nearly 30 years. The Bureau of Land Management, in cooperation with the Humane Society of the United States, is treating nearly 900 mares from wild horse herds in Idaho, Nevada and Utah this year in an effort to control that species.

Unlike GonaCon, PZP doesn’t have to be injected manually, says Stephanie Boyles, the Humane Society wildlife scientist. Wild horses are drawn to temporary corrals baited with food or water, injected by a dart containing the PZP and released. That’s a big improvement over the BLM’s current program of rounding up frightened horses by helicopter and confining them in holding pens, Boyles says. “The technology continues to get better and better all the time,” she adds.

Even Congress has taken notice. In February, Rep. James Moran, D-Virginia, called the BLM’s use of holding pens for wild horses “enormously wasteful and misguided” and said contraception would be cheaper and more humane.

Skeptics, however, question whether contraception should be used on wildlife at all. When public input was solicited on various proposals for dealing with the elk and the damage to their habitat, some people were “strongly in favor of fertility control, and some were strongly opposed who felt it was unnatural,” Patterson says.

“Some things are meant to be wild,” Powers says. “At some point, do we not want to treat them like domestic animals and be handling them? I think it’s important to point out that this is no silver bullet so that we don’t have to kill wild animals. Any time we’re manipulative with wild animals, we’re messing with natural selection.”

Boyles counters, “Any intervention could be construed as tampering with the natural process” — including culling. “If that’s not animal husbandry as well, I don’t know what is.” The reason there are wildlife imbalances, she notes, is because humans eradicated predators, such as at Rocky Mountain National Park.

Powers agrees. “We’ve changed the ecosystem,” she says. “We’ve created an artificial situation.”

Few argue that free-ranging wildlife populations can be reduced by contraception alone. Its best use may be with animals that are confined to some extent by either geography or fences, Powers says.

“It probably is more valuable in a confined setting than an open setting,” Lowell Miller, the lead researcher in the development of GonaCon, says of that vaccine. “It’s a lot more work (in an open setting), but it can be effective. I think as time goes on, we’ll determine how practical a tool it is.”

About Larry Keller

Comments

  1. adam gall says:

    This is insane. Here’s an opportunity for our park system to actually make a little additional money, feed a lot of people who could really use it, and maybe even fix yet another human created ecological mess.
    Instead they opt for an expensive, experimental birth control process? Why can’t these professionals trained in the field of science and ecology stick to ecological principles that have stood the test of time since time began? Predation works…be it in the form of natural predators or humans establishing a temporary hunting season.
    This article is frustrating to read…I’m shaking my head on this one.

  2. Inky says:

    Reintroduction of wolves into Rocky Mountain National Park makes sense ecologically, but would be a nightmare politically, what with the ranchers and home-owners surrounding the park.
    Wolves would return the ecosystem back to normal, as they’ve done in the Greater Yellowstone. However, Interior and CDoW don’t want to mess with wolves just now — not before the 2012 elections.
    Adam, if you think tinkering with contraception is a bit extreme, take a look at the feeding grounds in Wyoming, where WYG&F;are artificially maintaining an elk population that exceeds the carrying capacity of the area, just to keep hunters and outfitters happy. Meanwhile, the feeding grounds are a Petri dish that infects the herds with brucellosis and will inevitably infect the herds with chronic wasting disease. You’re right. It is all quite insane.

  3. Dave Skinner says:

    This is pretty stupid.
    Either establish a hunt, a real hunt, or — do it the Wyoming way:
    Put a couple packs in Rocky Park with a 10 or 20 mile no-shoot buffer. Wolves would be okay inside that line, dead meat outside. Simple, sensible, and with morons like Moran in Congress, impossible.

  4. prowolf says:

    The use of birth control, the sharp shooting, or hunting, none of it is going to change the feeding habits of the Elk. Only predators, such as the wolf, will force the Elk to move around and quit grazing the lowlands. They tried killing the Elk in Yellowstone and it didn’t work, their habits still remain the same. Only through reintroduction of wolves were the Elk populations brought under control and habitat allowed to once again flourish.

    Sadly, I don’t see Wolves being brought into Colorado thanks to the cattle and sheep barons who think they own the world.

  5. Neda DeMayo says:

    We have restrained the natural movement of wildlife and therefore it seems only ethical as responsible stewards, to look to minimally intrusive and humane management alternatives. The option of sharp shooters is wasteful and sets a negative example to younger generations.

  6. prowolf says:

    The one thing that the article does not mention is the fact that all of the meat is donated to needy families, so it is not going to waste.

    Personally I think that the birth control is going to be found to be a bad idea. You are messing with natural instincts and to an extent it could have a potential psychological impact on both the bulls and cows. And as mentioned, you are interfering with natural selection. Are you picking the best cows for testing and leaving inferior gene pools? Do you know which cows would have the stronger offspring?

    As usual APHIS thinks they may have the answer. Funny thing is, they were the ones who introduced CWD into Colorado through their testing programs. Hopefully this isn’t another one of their disasters in the making.

  7. Inky says:

    Dear Todd,
    Please spend a few moments with Google Scholar and search for articles containing the word “wolves” AND “aspen regeneration.” If you narrow the search to say, the last few years, you’ll find the research that has you all excited. Take a few minutes more, and you’ll find many more scholarly papers that say the exact opposite, even claiming photographic evidence that aspen are regenerating under the influence that wolves have on elk winter movements.
    Now, I cannot explain the discrepancy. Nor, I imagine, can you. As painful and potentially traumatic as this might be, perhaps you could be just a teensy-bit less dogmatic? It appears that the study you cite is something of an outlier, and while interesting, is not the final word on the issue — even though you want it to be.

  8. BitterrootBob says:

    Release the wolves. Why should Montana, Idaho and Wyoming monopolize all the fun? Could also do nothing as the wolves will disperse there pretty soon anyway.

  9. Mickey Garcia says:

    “Let them eat elk.”

  10. Paul says:

    I happen to live in Colorado and can tell you the elk are overpopulated and need to be seriously thinned down. Reintroduce wolves and they will thin these elk herds down a bit.

  11. Nicolai_in_HI says:

    Personally, I’m a fan of hunting, but here’s what I found myself wondering while reading this article:

    What are the side effects?
    I could be very wrong but GnRH is relatively new (for deer) and manipulating an animals hormones messes with the social and sexual behavior of the animal. Also consider that these vaccines mess with the immune system and can have inhumane side effects in a portion of the animals (i.e. the abcess). The risk of unwanted side effects has traditionally been high.

    Contraception, culling, administering a hunting season, and/or introducing predators such as wolves, are all all rather expensive solutions to this problem. The cheapest solution is to do nothign and accept the degredation. Contraception is by far the most expensive and has so far been the least practical. Therefore, managers, as well as the citizens of this country and the polititians they influence, are going to have to weigh the pros and cons, and decide whether or not they want to spend the extra money using a less effective method, considering the side effects (which may not be as “humane” as we initially thought). We need to look at the long term effects on the animal.

    My personal opinion is that it’s potentially a lot of meat to feed people. In these times, free range, all natural, 100% organic meat is a valued comodity. …and for the record, I am not a fan of high stocking densities to satisfy hunters.

  12. Paul says:

    And it’s a lot of meat to feed wolves. bring wolves in and let them do the job they were given.

  13. Nicolai_in_HI says:

    Paul, you could do that. However, everybody should consider such a move from a neighboring ranchers standpoint, who will receive few of the benefits of having wolves but will bear most of the problems. When wolves leave the park and kill their animals, would you be opposed to your tax dollars compensating them the value of that animal? If so, then you might have a winning deal.

    I found this page:
    http://www.defenders.org/resources/publications/programs_and_policy/wildlife_conservation/solutions/statistics_on_payments_from_the_defenders_wildlife_foundation_wolf_compensation_trust.pdf

    According to this link, compensations had risen over the years and peaked at $226,891 in 2008. I don’t know how much it costs to put on an elk hunting season, but I would bet it wouldn’t cost any less. Groups such as Defenders of Wildlife added much to this wolf compensation trust.

    Hence reintroducing wolves is looking better and better.

  14. Paul says:

    The wolves will have PLENTY OF FOOD outside the park. Jut incase you didn’t know this, Colorado has the highest elk population in the united states. Wolves will have plenty of elk to kill once they get done thinning the elk in the park.

    paul

  15. peck says:

    Wild Horses and birth control! When will we come to our senses and just do away with this non-native animal that is distroying mule deer habitat?

  16. prowolf says:

    I think peck is seriously confused. It is NOT the wild horses that are destroying the mule deer habitat. It is the welfare ranchers with their open range cattle on public lands where they do not belong. Get rid of them and all of our public lands will be far better off.

  17. jason says:

    Wow how wasteful, why not let hunters buy licenses and elk tags and help the states economy make some money, and hunt the elk.Elk meat is by far the best meat there is. Its free range, and organic and gets to have a happy life.Thats not what your getting at the grociery store,cramped animals in confined living conditions full of hormons.Hunting is the sane solution, not wolves, not birth control,let them be pused by sportsmen.

  18. krista says:

    Why introduce wolves to Colorado how would the people of Colorado benefit from wolves?Look what has happened in Idaho and Montana that would be a stupid thing to do.I dont see the problem with hunting the elk.It seems like a no brainer.I know how expensive elk meat is in stores.Why would you want to waste it on wolves.

  19. burgers says:

    Mmmm just buy more McDonald burgers. That will ensure the survival of the ranching industry! How dare those wolves reclaim some of their natural roaming lands! Since wolves pray on the sick and weak that is less of a chance that my family will get tainted meat. Common sense 101 tells any somewhat intelligently inclined person that wolves are not going to risk getting hurt by taking down a champion bull elk. An injury could mean their death. Instinct has programmed that into them. What’s the next best? take down the sick and weak. LEss chance to be maimed and better chance at food. Now the sick is culled from the herd and less of a chance of its disease to spread or genetic flaw to be passed on. Don’t know about you guys but i don’t like feeding my little girl sick meat.