By Kirk Robinson, Founder and CEO of Western Wildlife Conservancy
August 21, 2015
Dear member of the Utah Wildlife Board,
I was one of two “non-consumptive” members of the cougar committee that produced the new cougar management plan as directed by the Wildlife Board. It is the third such plan that I have worked on. I am writing because I wish to explain that my support for the plan is contingent upon how it is implemented and is qualified by a concern that it is not informed by the best scientific information available.
The new plan has many virtues, one of which is its relative simplicity and ease of implementation. However, it easily allows for the killing of too many cougars – too many in the sense that cougar population age distribution, social relations, and home range tenure can be seriously disrupted with no discernible benefit to prey species, plus a higher incidence of conflicts with humans. Indeed, given the low average age of Utah cougars, as determined by cementum annuli analysis of pre-molar teeth from killed animals, too many cougars are being killed in Utah now, with the number slowly creeping upward over the last several years.
- Utah wildlife management results in too many dead cougars.
The mean age of Utah cougars, as reflected in the annual hunt mortalities since 1990, is very young, averaging only about 38 months for males and females combined. To give you an idea of how young this is, it is not sufficiently long for a typical female to rear even one litter to age of independence (taking into account the average age of sexual maturity, first pregnancy, gestation and age of independence). That would take more like a minimum of 44 months. Nevertheless, if the percentage of females killed in the annual hunts is kept at a low enough level, this will still be enough to ensure a fairly stable population size, but the animals will on average be very young. This is a poor way to manage any species – as if it is any of our business to meddle with something so fundamental, never mind the potential in an incidental increase in cougar-human conflicts. Yet this is in fact the situation we have had in Utah for many years due to the excessive number of cougar permits sold each year, which in turn is largely driven by the number of “predator management units” where high quotas are set, ostensibly to help boost ungulate herds such as deer and elk.
- Cougar management based on the best available science?
The passage quoted below is excerpted from the Utah Predator Management Plan, adopted by the Utah Wildlife Board in 2006, which was distributed to the cougar working group. It states that the Division must act on the best available scientific information. Director Sheehan recently reiterated this very point in his response to a letter forwarded to me containing comments on the plan submitted to him by the Human Society of the United States, stating that the new plan is informed by the best available scientific information. Unfortunately, he didn’t do much to substantiate this claim and I believe he is wrong.
“Managers must recognize the role of predators in an ecological and conservation context. The effects of removing one predator species may result in a population increase of another predator species. Division actions must be based on the best available scientific information. In addition, prey populations are affected by a multitude of factors. If reducing predator populations does not have the desired effect on prey populations within a reasonable time frame, other overriding factors need to be addressed and further efforts to reduce predator populations may not be warranted.” Utah Predator Management Plan 2006 (my emphasis)
It is entirely reasonable that this prescription should apply to all Division actions, not only those that concern predatory species. Why would a wildlife management agency choose to act on anything but the best scientific information available, unless for political or economic reasons? Yet the cougar plan is designed to accommodate predator management plans that have no sound basis in science. Indeed, the best available scientific information indicates that predator management plans, except possibly for the sake of transplanted bighorn sheep, are obsolete.
By its very nature, properly conducted science is self-correcting. This fact is precisely what differentiates science from hunches, dogma, superstition and the like. Because science is self-correcting, scientific understanding tracks truth. And that’s why we must guard against efforts, however worthy they may seem, to substitute popular lore for scientific understanding. Imagine where medical science would be today if we had not gotten past the snake oil salesmen of the 19th Century. Imagine where our understanding of the cosmos would be if we relied on simple, unaided observation of the sky to determine whether the sun revolves around the earth. I am concerned that DWR, under pressure from some sportsmen and livestock organizations, is substituting snake oil for sound science.
Biologists have learned much about mountain lions and their interactions with prey species since the first Utah cougar management plan, adopted in 1999. We now know, for example, that killing more cougars, short of an all-out war against them, will not predictably result in fewer human-cougar conflicts. But in the absence of real knowledge of the scientific facts, simple reflection suggests that if we kill more cougars, there will be fewer cougars; and if there are fewer cougars there will be fewer cougars killing deer, elk, sheep, cattle, etc., and fewer cougars wandering into residential areas and preying on pets. But this is not the case.
First, unlike deer and elk populations, cougar populations are limited by available prey and by their habitat needs. Cougar populations thus naturally adjust to prey abundance and available habitat. They in turn keep prey abundance within an optimal range with respect to nutrition provided by prey habitat. (When cougars and wolves were exterminated on the Kaibab Plateau in the 1920s, the result was destruction of the range, massive erosion, and a huge deer die-off due to starvation, just as predicted by Aldo Leopold.)
The so-called predator pit hypothesis, relied on by the Division of Wildlife Resources as its justification for predator management units, is just that – a hypothesis. Indeed, there is precious little evidence, if any, that it applies to Utah mule deer herds. Yet the entire predator management program, as it applies to mule deer, rests on it – never mind that mule deer abundance is influenced mainly by the available nutrition, hardly at all by predation, particularly over a period of years. (Bishop et al. 2009; Pojar and Bowden 2004) It is worth noting, also, that possibility and probability are two entirely different things. The mere possibility that killing more cougars will result in more deer is nowhere near a probability that it actually will result in more deer. Similarly, the mere possibility that there is a vein of pure gold under your front lawn does not in any way amount to a probability that there is.
Second, mortality to prey animals from cougar predation is almost entirely compensatory, not additive. This means that cougars take mostly prey animals that are destined not to contribute to reproduction or recruitment in the future, either because they are too weak, to sick or too old to do so, and which for that very reason will soon be removed from the population regardless of whether they become victims of predation. This is why, as shown by a recent long-term study in southeast Idaho, researchers were not able to detect a noticeable relationship between cougar removal and mule deer fawn recruitment. Similarly for coyote removal. Here is what a stellar team of scientists recently found right on Utah’s northern border:
“Annual removal of coyotes was not an effective method to increase mule deer populations in Idaho because coyote removal increased radio collared neonate fawn survival only under particular combinations of prey densities and weather conditions, and the increase did not result in population growth. Coyote-removal programs targeted in areas where mortality of mule deer fawns is known to be additive and coyote-removal conditions are successful may influence mule deer population vital rates but likely will not change direction of population trend. Although mountain lion removal increased mule-deer survival and fawn ratios, we were unable to demonstrate significant changes in population trend with mountain lion removal. In conclusion, benefits of predator removal appear to be marginal and short term in southeastern Idaho and likely will not appreciably change long-term dynamics of mule deer populations in the intermountain west.” (Hurley, et al. 2011)
Third, because cougar hunters generally prefer trophy animals, they will tend to select for large resident toms, which play a role akin to a police force in cougar populations to limit the density and total number of cougars and to maintain social order. When they are removed, especially in large numbers, the juveniles have the run of the place; and because they are not skilled hunters with a good knowledge of the habitat, they tend to prey to a disproportionate extent on domesticated animals and pets when they can. (It stands to reason that they are also more likely to see human beings as potential prey, especially if they are starving. This should be a matter of concern. Also, young transient males move in and will frequently kill kittens not sired by them). Perhaps the most knowledgeable of all cougar researchers, Ken Logan, who has conducted a number of cougar studies in at least four different states, stated this at an event held at the Swaner EcoCenter in Park City this last spring. Here is what an expert team of Washington State researchers who investigated this topic recently wrote:
“Cougar (Puma concolor) populations are a challenge to estimate because of low densities and the difficulty marking and monitoring individuals. As a result, their management is often based on imperfect data. Current strategies rely on a source-sink concept, which tends to result in spatially clumped harvest within management zones that are typically approximately 10,000 km2. Agencies often implement quotas within these zones and designate management objectives to reduce or maintain cougar populations. We propose an approach for cougar management founded on their behavior and social organization, designed to maintain an older age structure that should promote population stability. To achieve these objectives, hunter harvest would be administered within zones approximately 1,000 km2 in size to distribute harvest more evenly across the landscape. We also propose replacing the term “quota” with “harvest threshold” because quotas often connote a harvest target or goal rather than a threshold not to exceed. In Washington, USA, where the source-sink concept is implemented, research shows that high harvest rates may not accomplish the intended population reduction objectives due to immigration, resulting in an altered population age structure and social organization. We recommend a harvest strategy based on a population growth rate of 14% and a resident adult density of 1.7 cougars/100 km2 that represent probable average values for western populations of cougars. Our proposal offers managers an opportunity to preserve behavioral and demographic attributes of cougar populations, provide recreational harvest, and accomplish a variety of management objectives. We believe this science-based approach to cougar management is easy to implement, incurs few if any added costs, satisfies agency and stakeholder interests, assures professional credibility, and may be applied throughout their range in western North America.” (Beausoleil et al. 2013)*
- Folklore, not science, dictates how cougars are managed in Utah.
Unfortunately, the process that the Utah cougar committee went through did little to ensure that the participants had an adequate understanding of the relevant science in these crucial areas. Some of the science was made available to them, though the ensuing discussions indicated little understanding or appreciation of it – very little indeed. It was as though the scientific references were merely items on a menu that members of the committee were free to choose from as they wished. I seriously doubt if many of the participants, aside from me and my one counterpart, even read the material. Dave Stoner, a Utah cougar researcher, did present some of this information to the committee members in one of the meetings, but it did not generate much discussion. It was as though it really didn’t matter. Furthermore, from my point of view, DWR personnel were derelict for doing little to motivate or encourage members of the committee to take the science seriously. They behaved more in the fashion of waiters and waitresses, serving up whatever the majority ordered from the menu, rather than as true leaders.
Regarding the oft-repeated canard that Utah cougar plans are the result of consensus among representatives of many interest groups, a much clearer picture of reality emerges as soon as one realizes that the so-called non-consumptive voice is always overwhelmed by opposing voices about 6:1. The committees are purposely set up this way. This is especially unfair given that a sophisticated public opinion survey commissioned by the Utah Division of Wildlife Resources (the “Krannich-Teal report”) showed that most Utah citizens disagree with how our cougars are managed. By rights, they should have the greater share of representation on cougar and other wildlife planning committees.
- Appropriate performance targets
There is one issue in particular that illustrates my concern. The 1999 Utah cougar plan included the following five performance targets, as did the 2009 plan:
- The percent of animals in harvest over 6 years of age averages 15% or
- Total adult survival of 65% or more.
- The percent of females in the harvest is less than 40%.
- The number of cougar treed per hunter day averages 0.38.
- Reduce the number of units being managed by a predator management
These targets were replaced with the following two in the 2015 plan:
Primary Target – Proportion of all females in the harvest < 40% (within a management area averaged over 3 years)
Secondary Target – Proportion of cougars ≥5 years old in harvest between 15-20% (within a management area averaged over 3 years)
I wish to focus particularly on this secondary target. First, notice that it is only a secondary target, not a second target. This already suggests that it is not to be taken too seriously. Second, DWR personnel have stated repeatedly, as their reason for the change, that the Division was never able to meet the original target from the 1999 plan. Indeed, they never did meet it, which I complained about at RAC and Wildlife Board meetings for several years. However, it is also true that the Division never seriously tried to meet it. They never recommended or adopted a single strategy for achieving it. Instead, no doubt under pressure from various special interests, they simply decided to lower the bar by dropping it and substituting the new “Secondary Target” that they were already meeting.
Bishop, C. J., G. C. White, D. J. Freddy, B. E. Watkins, and T. R. Stephenson. 2009. Effect of Enhanced Nutrition on Mule Deer Population Rate of Change. Wildlife Monographs:1-28.
Hurley, M. A., J. W. Unsworth, P. Zager, M. Hebblewhite, E. O. Garton, D. M. Montgomery, J. R. Skalski, and C. L. Maycock. 2011. Demographic Response of Mule Deer to Experimental Reduction of Coyotes and Mountain Lions in Southeastern Idaho. Wildlife Monographs:1-33.
Monteith, K. L., V. C. Bleich, T. R. Stephenson, B. M. Pierce, M. M. Conner, J. G. Kie, and R. T. Bowyer. 2014. Life-history characteristics of mule deer: Effects of nutrition in a variable environment. Wildlife Monographs 186:1-62.
Pojar, T. M., and D. C. Bowden. 2004. Neonatal mule deer fawn survival in west-central Colorado. Journal of Wildlife Management 68:550-560.
Wielgus, R.A., G. M. Koehler, B. T. Maletzke, B. N. Kertson, R.B. Wielgus. 2009. Research to Regulation: Cougar Social Behavior as a Guide for Management. Wildlife Society Bulletin; DOl: 10.1002/wsb.299
*Cougar study finds old toms more stable for wildlife
A new study out of Washington seems to contradict some old theories on mountain lion hunting.
PULLMAN, Wash. — Overharvest of cougars can increase negative encounters between the predator and humans, livestock and game, according to a 13-year Washington State University research project. Based on this, the Washington Department of Fish and Wildlife is implementing a new cougar management plan.
Starting in January, Washington will employ equilibrium management — hunters will remove no more than the surplus of animals that would be generated through natural reproduction.
This means that each of the state’s game management units will have a quota allowing for harvest of no more than 14 percent of that area’s cougars. Once the limit is filled, cougar hunting will be suspended for the year in that unit. Hunters will be allowed to take their tags to other units that haven’t reached the limit.
Teens mentally ‘not all there’
For years, cougar management operated on the presumption that every cougar shot meant one cougar less to prey on livestock, game and pets. But the 13-year study headed by Rob Wielgus, director of WSU’s Large Carnivore Conservation Lab, has overturned that presumption.
After years of data collection, researchers made a surprising observation. Whether hunters killed 10 percent or 35 percent of cougars, the population remained the same. The old paradigm of wildlife management would explain this by saying the remaining population increased reproduction to make up for hunting. But this was not the case.
In fact, reproductive success actually decreased. Data showed that adult males, “toms,” are intolerant of adolescent males and will kill them to maintain their territory and breeding rights. Juvenile males can only survive by avoiding adult males. When hunting removes most adult males, the adolescent males survive and cause all sorts of trouble.
While adult cougars tend to avoid humans and livestock, juveniles are less cautious: “They’re teenagers,” explained Wielgus. “They’re sexually mature, but mentally they’re not all there.”
Migration, reproduction, mortality
This is compounded by the fact that adolescent males have larger territories than mature toms, but don’t maintain exclusive territories as do adult males. Livestock and elk herds might have one mature tom in the area, but removing that tom could bring in three or four adolescents, multiplying troubles.
Without adult male protection of females and their litters, infanticide becomes a problem, as the young toms kill kits to bring the mother into heat and improve their breeding chances. The females try to protect their litters by moving higher in elevation, away from dangerous adolescent males, but also away from plentiful whitetail deer and into terrain occupied by less abundant prey such as mule deer, bighorn sheep and woodland caribou. Thus marginal game populations suffer.
Research methods included capturing cougars with hounds and attaching collars with global positioning system receivers and radio transmitters. The collars reported the cougars’ locations six times a day, allowing researchers to generate valuable data on cougar migration, reproduction, prey and mortality.
Read more: http://billingsgazette.com/lifestyles/recreation/cougar-study-finds-old-toms-more-stable-for-wildlife/article_c1cd48cf-6eb1-5879-ade7-9b9a0d22a73a.html#ixzz28dL5zdZe
Photo: © Werries2 / Dreamstime.com