Population management of predatory carnivores in the mid-western United States

 

Background

Among the flourishing peace, love and cultural progress that took our country by storm in the mid-1900’s a midwestern ecosystem was facing one of its biggest hits yet, at risk for an entire collapse. The collapse that we believed to have been appeased threatens our country yet again. This human-habitat turmoil had been brewing for over one hundred years when expansion in the 1800’s brought humans and their livestock into direct contact with canine carnivores. As human habitat encroachment displaced ungulate populations that need large territories to live, wolves began to prey on the livestock. Farmers were complaining of livestock losses due to coyotes and wolves and canine carnivores were quickly becoming the nation’s newest pest. In the early 1900’s Theodore Roosevelt, normally known for his environmental preservation activism, described these animals as “beasts of waste and desolation” advocating for their extermination (Johnson, 2002). A culture that has always seen wolves as the villain in popular fairy tales like The Little Red Riding Hood, and in which the werewolf was growing in popular culture as a horror monster, was finally taking actions against the canine carnivores. A modern organization that goes by Mission Wolf described this phenomenon as the “war against the wolf”, this battle being fought in the midwest (2014). Farmers and civilians took matters into their own hands, piling up skulls and pelts as trophies, and effectively eradicating the populations from most midwestern states (White, 2014).

We follow the declining wolf populations to 1960’s Isle Royale- a national park on Lake Superior off the coast of Michigan. A change in forest vegetation progression moved caribou out of the area and brought in moose and deer. An abundance of new resources led to an the rise of the cervid’s populations. Canid predators were their only sources of population control, keeping the herd numbers lower than the resource availability would allow. In a famous example of apex predator importance, the carnivore cleansing movement that reduced canid carnivore populations to an alarming low created a devastating effect on the environment (Vucetich, 2012). Using situations such as this, researchers suggest carnivores play a vital role in maintaining the ever delicate balance of ecosystems. The drastic reduction of the canid populations had a detrimental cascading effect on the ecosystem. As the predator populations declined, the cervid populations were no longer held in check and boomed. The newly increased moose and deer populations over grazed their environment and decimated the native habitat (Vucetich, 2012).The disruption in the vegetative ecosystem led to the lack of resources for many birds and smaller mammals, either displacing or eradicating those species as well. A whole ecosystem was effectively wiped out due to the loss of its keystone species- the coyotes and wolves. Not only were we killing off the wolves themselves but other harmless native species and habitats were becoming threatened as well. This unfortunate sequence of events was repeated in other parts of the Midwest as well, such as Yellowstone National Park. A population survey in 1970 found zero wolves left in the reserve land (National Park Service, 2014).

Thankfully the public caught wind of this before it was too late. The Endangered Species Act was passed in 1973, and began to protect the decimated populations. By the 1980’s restoration programs were being set into place and hope for the wolves began to become a reality. Canid populations began to reestablish in the land and finally in 2011 the Grey Wolf was delisted as an endangered species (National Park Service, 2014). Ecosystems have bounced back and the habitats seem to be finally coming back to a healthy and normal state. However, our current mismanagement of the canine population yet again threatens to disrupt this delicate ecosystem.

 

The Problem We Are Facing

With the reestablishment of carnivore populations we are yet again facing the threat of livestock damages due to predation. Cattle and calf losses from animal predators represented 5.5% of the total deaths from all causes (USDA). Although a minimal percentage, it is still a monetary loss that can be prevented. Population control techniques can be implemented to aid in this loss prevention. However, the USDA primarily practices the same technique that eradicated the populations in the past- sharpshooting. Everything comes down to money, and taxpayers are paying 40-50% of the costs to aerially sharp shoot coyotes and wolves (Wetzler 2013). It costs $865/hr for the use of a helicopter per mission, which averages about $800 for each coyote or wolf (Wetzler 2013). When multiplied by the 100,000 wolves and coyotes killed annually the public is doling out about $43,250,000. Over forty million dollars is being spent each year for only about 5% of livestock in the entire country. While the monetary hit to farmers from predation can be significant, the current practice is too costly for such an ineffective, and ecologically damaging solution. A less expensive and longer lasting program needs to be established in order to reduce costs on all sides.

 

Resistant Audience

There is a belief that sharpshooting is the best solution to the problem, however this is a short term fix to a long term problem. More importantly, there are other non-lethal methods used that display more effective results than sharpshooting. Non-lethal methods such as the use of guard animals, fencing and frequent land checking are also effective methods preventing predation at rates of 36.9%, 32.8% and 32.1% respectively (USDA, 2010).

Bullets are initially cheaper than alternative practices, and if the problem is only one or two carnivores it makes sense to just shoot the predators. According to the National Resources Defense Council, “the United States spends… $100 million of taxpayers’ money a year to kill a 100,000 predators.” (2013). This is a massive amount of money being allocated for predator control, and if a farmer or park ranger finds a pack hunting on farmland, they have the right to shoot at the animals. On a small scale, case-by-case basis, shooting at carnivorous canine predators is not an issue.  An issue is land based sharpshooting can add up quickly, costing anywhere from $108 to $121 (The Wildlife Society Bulletin, 2001).

On a large scale, the use of alternative methods is less expensive and less demanding than the annual high cost of sharpshooting. The common belief is sharpshooting clears an area of livestock predation. However, sharpshooting actually increases the number of coyotes and wolves because if a pack is culled, a new pack is introduced to the area. This new pack will reproduce at a larger rate in response to newly acquired food sources and habitat. Peter DeFazio, a representative of Oregon, heatedly stated to the congress that during a study period where sharpshooting of coyotes in Oregon was allowed, “coyote populations have tripled” (Natural Resource Defense Council 2013). Additionally, he commented sarcastically “It’s ineffective, it’s inhumane, and it’s expensive, but other than that it’s a great idea” (Natural Resource Defense Council 2013). According to the Entomology Department at Purdue University, a small pack litter size averages three pups, while a large pack litter size can be up to twelve pups. Breeding is dependent on supply and demand. If there is more food, there will be more puppies, alternatively if there is less food, there will be less puppies. Statistically, if a pack of eight female coyotes is culled from an area and a new pack of eight females takes over, within the following year, that area could hypothetically see ninety-six new coyotes the next spring. While aerial sharpshooting may cause temporary respite from predation, it is not a permanent nor sustainable fix.

Hunting livestock is a viable option for coyotes and wolves and even though farmers are in uproar after the death of their animals, there are alternatives to prevent it. The main goal is for better management of carnivores and livestock.  Coyotes and wolves are naturally cautious animals, so scaring devices such as firecrackers, sirens, strobe lights, noisemakers or flags tied to ropes or fences can effectively keep predators from entering farm property (Fox 2012). Additionally, “new studies on conditioned taste aversion show promise in protecting crops, eggs and fruit from mammals (Fox 2012). Training predators to dislike farm-produced products is another strategy; if dogs can be trained to not jump up on the dinner table, a coyote can learn to not raid the lamb barn. However, the most important management practice which needs to be strictly enforced is the removal of dead carcasses. On farms where cattle roam for hundreds of acres, it is difficult for farmers to manage individuals on a day to day basis, and as a result death occurs to animals from other reasons than predation. It is imperative for farmers to remove these carcasses, because the smell and pheromones released from the animal attract the predators (Fox 2012). Instead of going out and sharpshooting predators after seeing the death of livestock, it is more economical and humane to implement these techniques to help save the life of the predator and prey.

Many people believe the presence of a coyote or wolf pack is a threat, but there is viable research to prove having these species in the area is beneficial. According to Fox in the 2012 article Why We Shouldn’t Kill Coyotes,

…an increasing number of farmers recognize coyotes as beneficial predators, offering free rodent control among other ecosystem services… These coyotes will also keep away transient juvenile coyotes that are prone to prey on domestic animals.

Having coyotes or wolves in an area should not cause an automatic need to eradicate the pack. Ecosystems are extremely fragile and even the smallest changes create a disturbance. Eradicating a pack of primary consumers such as wolves and coyotes increases the number of prey species such as deer, rabbit and rodents. By maintaining a population of consumers, they will sustain the number of predators, and the predators will support the fauna they need to survive. Going out and culling a pack of coyotes or wolves may seem like the right management decision, however by reducing the presence of these carnivores significantly affects other species within the ecosystem.

 

There Are Better Alternatives

Livestock loss due to predation is one of two main catalysts for predator sharpshooting, the alternate designated for the restoration of ungulate species. According to MacGregor, Perkins, Asa & Skinner (2012), “the number of coyotes removed (60,000–100,000) yearly has been consistent since 1977”, and livestock loss has not changed either (para. 2). In a petition to ban aerial gunning, WildEarth Guardians Carnivore Director, Wendy Keefover-Ring states that of the 13,375,311 animals that Wildlife Services killed between 2004 and 2008, 561,353 mammalian carnivores were slaughtered, the majority being coyotes (p. 5). Predation is not the main cause for livestock loss. Only .18% of cattle die from predation a year, and only 3% of sheep are lost annually to predation (Keefover-Ring p. 25). The director accuses farmers of exaggerating the number of livestock lost annually due to predation (Keefover-Ring p.25). In a study done to examine the main cause for sheep death, two farms, one within coyote territory and one with no coyote predation, showed the same production decrease, not due to predation, but due to market conditions unfavorable towards the sheep industry (Keefover-Ring p. 24). Factors such as the cost of feed, the sale price of lamb, and weather conditions all factor into the farming industry, making it a risky business to be in. Furthermore, researchers have found no direct correlation that links lamb death to coyote predation (Keefover-Ring p. 24).

Realistically, everything comes down to money, and taxpayers are paying 40-50% of the costs to aerially sharp shoot coyotes and wolves (Wetzler par.2). It costs $865 an hour for a sharpshooter to take out a helicopter (Wetzler par.1). Taxpayers are paying 50% of $865 multiplied by the 100,000 wolves and coyotes killed annually that affect less than 5% of livestock populations. That is about $43,250,000 of taxpayer money designated to the protection of 5% of livestock that could be protected by non-lethal means.

Not only are there problems with the results of sharpshooting, but there are serious flaws in the methods as well. Aerial sharpshooting is hazardous not only to the animals, but to the pilot and hunter as well. These helicopters are flying at very low altitudes and low speeds, and the pilot is not looking up, but down at the wolves. According to records presented by Keefover-Ring, since the year 1973, there have been over 119 accidents involving aerial sharpshooting, resulting in seventy injuries and thirty eight deaths (Keefover-Ring p. 9).  This is a result of helicopters either flying into telephone wires, or helicopters swooping back to re-shoot animals and flying into the opposing wind pattern (Keefover-Ring p. 9). Hunters also accidently shoot at the helicopter and damage vital parts.

Not only is aerial sharpshooting dangerous, it is critically unregulated. In 2009, a former Wildlife Services employee came forward with information that federal employees aerially attacked mountain lions in Nevada for the sole purpose of having a trophy (Keefover-Ring p.8). While this was not an attack on a coyote or wolf, this indicates there are no means of controlling federal employees with access to a helicopter and a gun.  In fact, some do not even need a helicopter. Carl Ball of Idaho shot a pack of wolves, illegally, from a powered parachute (Keefover Ring p. 9). Interestingly enough, Ball was protecting cattle on a farm owned by Idaho State Senator Jeff Siddoway who gave Ball permission to shoot the wolves, which was out of his jurisdictional power (Keefover-Ring p. 9). While permits are required to aerially sharp shoot, there is no means of regulating those who actually do hold those permits.

Another cause for concern is the success of sharpshooting. While it is clear that pilots do circle back and kill off entire packs, the fact that they have to circle back that is concerning. Even skilled sharpshooters have a very difficult time getting a clean shot at a coyote or wolf running as fast as it can. The animals are hit and suffer until the helicopter has time to loop back and shoot a second or third time. Sometimes, the hunter loses the animal in the foliage and the animal staggers off to die from its wounds (Keefover-Ring p. 11).

The most statistically alarming concern with sharpshooting packs in result of livestock predation is the likelihood of sharpshooting the correct animals. Coyotes and wolves travel huge distances every day, and sharpshooting trips cover a five or ten mile radius (Keefover-Ring p. 10). It is highly unlikely that a coyote who travels twenty miles at night to raid a sheep farm is going to be in the same area three days later when Wildlife Services retaliates with a sharpshooting excursion. The only means of knowing if the venture was successful is if the livestock loss stops. As Wildlife Services former employee Gary Strader explains, “They might kill the right coyote the first time, or they may have to kill 100 coyotes before they get the right one” (Keefover-Ring p.10). This alarming level of inaccuracy also proves that aerial sharpshooting is ineffective in reducing loss just by considering the likelihood that the hunter is going to eliminate the culprit.

In order to come up with viable and successful alternative methods to lethal eradication of carnivores, basic biological and behavioral aspects of these populations must be considered. For example, in a three-year study, non-sterile coyote packs with pups killed six times as many sheep than packs without pups (Seidler 2009). When there are pups to care for, more food must be provided and parents will hunt out of their typical territories in order to feed their young. Therefore, one way to go about the predation problem is to reduce the number of offspring, and therefore stifle an increased need for food.

Reproductive hormone suppressants are not groundbreaking, they are used in domesticated dogs in the form of Deslorelin (MacGregor et al. 2012), and numerous forms are used for women to protect ovaries during chemotherapy and for individuals undergoing transgender processes. This reproductive suppressant is a GnRH antagonist that “…act[s] by binding to the GnRH receptors and provide competitive inhibition of the naturally occurring GnRH” (Magon, 2011). GnRH, or gonadotropin releasing hormone, naturally occurs in the body as stimulation for ovary production of estrogen (Magon, 2011). With the addition of GnRH antagonist, the production of GnRH is inhibited, and therefore, estrogen is not produced. Without estrogen, the female coyotes are unable to reproduce successfully. GnRH antagonist is promising because it can also be applied to males, by suppressing the production of testosterone.  In a study performed at the University of Wyoming Coyote Center, four adult male coyotes were treated with Deslorelin in various amounts. Testosterone production was then collected in three out of the four males (MacGregor et al. 2012). The studies report that at 47 mg of Deslorelin, “testosterone concentrations remain suppressed after 12 mo. In addition, no physiological changes were noted” (MacGregor, Perkins, Asa & Skinner 2012). While the sample size was small, this study provides pioneering research proving that injectable Deslorelin is able to suppress testosterone production for an entire year. Even more, the results hinted at a linear correlation, leading the authors to conclude that higher doses of GnRH antagonist could suppress successful testosterone production for an even longer duration (MacGregor et al. 2012). Not only have scientists found a non-lethal and behaviorally sound solution to overpopulation that works in both males and females, but they have also found a solution that could potentially last for numerous breeding seasons.

Coyotes are monogamous seasonal breeders, and mate in January and February, with litter sizes averaging six puppies (Purdue 2010). In the wild coyotes average two to four breeding seasons in a lifespan of six years. If just ten coyotes were injected with the GnRH antagonist, that could be a reduction of fifty to sixty coyotes the next year. Whereas the sharpshooting of ten coyotes only reduces the population of coyotes by ten. Statistically, the numbers prove that hormone suppressants are a viable and effective means of reducing puppy populations, and consequently, reducing livestock predation.

 

Here’s What We Can Do

In a documentary exposing lethal control methods of carnivores, a cattle rancher, with property prone to wildlife predation, opposes aerial sharpshooting. “It’s not about being better for the wolves or the calves or the grass, it’s about being better for the ecosystem” (Natural Resource Defense Council 2013). Statistics prove that the use of alternative, non-lethal methods of population control are more effective, naturally sustainable and reap more economic and ecological benefits than traditional sharpshooting practices. However, these sharpshooting practices continue to be one of the dominant population control methods. The USDA allocates $96 million to the control programs that prevent predator damage to livestock and crops a year, funding lethal methods such as sharpshooting and trapping. Since trapping is a relatively inexpensive, yet small-scale process, approximately 2/3 of the designated $96 million taxpayer dollars spent goes to aerial sharpshooting (USDA 2014). The United States Department of Agriculture should allocate the money spent on the ineffective sharpshooting practices to funding the development of already in testing hormone and birth control programs, incentives for farmers to use fencing and other barrier defenses, and research into other alternative methods such as immunosuppressive hormones that may extend the effectiveness GnRH antagonist, or predator alert pheromone scent marking on livestock land. Government funds can catalyze researchers to refine their findings and apply them to carnivores in field studies to find a new solution that is less invasive, ecologically damaging and costly. Using alternative methods not only benefits the canine carnivore populations, but these methods will benefit the midwestern ecosystem, the farmers and the USDA itself.

 

In Summary

Alternative methods are already in research, and scientists are finding significant results indicating that there are other ways to control predator populations alternatively to sharpshooting. If the USDA would transfer its funds it is wasting on the ineffective, and too costly for its benefit, process of sharpshooting these alternative methods can be refined into actual programs. Besides experimental programs there are the aforementioned processes, already underway, such as fencing, guard dogs and frequent checking of lands that all are, proven in the USDA reports themselves, to be significantly more effective at preventing livestock predation than sharpshooting anyways (USDA 2014.). Many studies are showing that using birth control in coyotes effectively renders the females infertile. This isn’t groundbreaking science, we use it in dogs and even humans to prevent pregnancy- extending this to wildlife populations is the most logical next step. Coyotes and wolves with pups tend to kill significantly more prey, livestock included. Preventing the pups from being born, versus gunning them in their dens or shooting their parents and leaving them to starve, is a preemptive measure to stop the problem in it’s tracks that is more humane, easier and cheaper to implement than retroactive treatments of problems.  We have seen the devastation that over hunting a population can do. A keystone predator population drop, even one not as drastic as the problem in the 1900s, can affect an ecosystem. Farmers will lose in crops what they will gain in the retention of predator losses due to the increase in herbivore populations stripping all local vegetation. Making canine carnivores infertile allows the populations to still exist and maintain the surrounding herbivore populations and the ecosystem already established, while preventing the growth of the species. Fencing, guard dogs and frequent land checks prevents any pest animals from entering whatsoever, preventing both animal losses due to predators and crop losses due to herbivores. With all of these other accessible resources available to control predation on livestock, the USDA is urged to reform its go-to processes and see the proof that there are cheaper, more efficient and more humane ways of tackling this problem.

 

References

 

1. Bromley, C. Gese, E. (March 26, 2001). Effects of sterilization on territory fidelity and

Maintenance, pair bonds, and survival rates of free-ranging coyotes. USDA National Wildlife Research Center – Staff Publications, 528, 385-392.  Retrieved from http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1524&context=icwdm_usdanwrc

2.  Doerr, M.L. McAninch, J.B. Wiggers, E.P. (2014). Comparison of 4 methods to reduce white-

tailed deer abundance in an urban community. Wildlife Society Bulletin, 29. Retrieved fromhttp://apps.webofknowledge.com/full_record.do?product=WOS&search_mode=GeneralSearch&qid=3&SID=1BuUBEFUmm8AzYK4uPE&page=1&doc

3. Fox, C. (2012). Why killing coyotes is the problem. Retrieved from

http://www.aphis.usda.gov/wildlife_damage/nwrc/publications/03pubs/gese031.pdf

4. Gese, E. M. (2003). Management of carnivore populations as a means to reduce livestock

losses: the study of coyotes in North America. In Coyote Depredation Management, 85-102. Retrieved from http://www.aphis.usda.gov/wildlife_damage/nwrc/publications/03pubs/gese031.pdf

5. Grey Wolf News. (2014). Livestock Attacks. Retrieved from

http://washingtonwolf.info/livestock_attacks.html

6. Johnston, J. (2002). Preserving the Beasts of Waste and Desolation:Theodore Roosevelt and

Predator Control in Yellowstone. Yellowstone Science, 21-28. Retrieved from http://www.nps.gov/history/history/hisnps/NPShistory/beasts.pdf

 

 

7. Keefover-Ring, W. (November 9, 2009). Petition for Executive Order and Rulemaking

Banning Aerial Gunning and Poisoning Activities of Native Wild Carnivores on Federal Public Lands. Retrieved from http://www.wildearthguardians.org/support_docs/petition_APA_11-23-09.pdf

 

8. Magon, N. (2011). Gonadotropin releasing hormone agonists: Expanding vistas. Indian           

Endocrinol Metab. 15(4), 261–267. doi: 10.4103/2230-8210.85575

9. MacGregor, M. Perkins, E. Asa, C. Skinner, D. (Sept. 30, 2012). Contraception has gone to

the coyotes. Journal of Zoo and Wildlife Medicine, 44(4s), S4-S8. doi:http://dx.doi.org/10.1638/1042-7260-44.4S.4

10. National Park Service. (2013). Wolf Restoration. [Data file] Retrieved from

http://www.nps.gov/yell/naturescience/wolfrest.htm

11. Natural Agriculture Statistics Service. (May 11, 2009). Cattle Death Loss [Data file].

Retrieved from http://usda01.library.cornell.edu/usda/current/CattDeath/CattDeath-05-12-2011.pdf

12. Natural Resource Defense Council, P. Natural Resource Defense Council, D. March 5, 2013.

Wild Things. United States: Natural Resource Defense Council.

13. Purdue University. (2010). Coyotes. Retrieved from

http://www3.ag.purdue.edu/entm/wildlifehotline/Pages/coyotes.aspx

 

 

14. Seidler, R. (2009). Surgical Sterilization of Coyotes to Reduce Predation of Pronghorn

Fawns. Digital Commons at Utah State University, 306. Retrieved from http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1277&context=etd

15. Vucetich, J. (2012). Wolves and moose of Isle Royale. Retrieved from

http://www.isleroyalewolf.org/overview/overview/at_a_glance.html

16. Wetzler, A. (2013). Just how much does it cost to kill a wolf? More than you think. [Web log

comment]. Retrieved from http://switchboard.nrdc.org/blogs/awetzler/just_how_much_does_it_cost_to.html

17. White, A. (2014). Mission: Wolf. Retrieved from

http://www.missionwolf.org/page/wild-wolf-history/