A male greater sage grouse struts on a lek. (BLM)

I appreciate Chris Madson’s efforts to include some of the historical context and study surrounding sage-grouse population cycles in his recent WyoFile essay, “Circular reasoning,” and I largely agree with his characterization of the history of population cycle research and his presentation of species biology. I agree that population cycles were overemphasized for years and that for many species claimed to undergo cycles, the evidence is lacking when confronted with data. However, rather than attempt to understand and embrace the complexity of population cycling, Mr. Madson seems to miss what can be learned from nonlinear modelling and rather conclude in response to his subtitle (“Are greater sage-grouse populations really cyclic?”) that sage-grouse populations are not cyclic and are simply in linear decline. 

Opinion

A more accurate answer would be: some populations are cyclic, some are not. As with so many questions in ecology, it depends on the time frame and the spatial scale considered. Rather than oversimplifying complex systems, I believe we should use the tools at our disposal and within reach to understand natural variation in the distribution and abundance of organisms. All conclusions regarding wildlife population change are based on models either explicitly or implicitly. And there is always a tradeoff between explanatory power and model complexity (see: Occam’s razor). We have to simplify the world in order to understand it and choosing the balance between simplification and capturing every detail (i.e., overfitting a model) is one of the most difficult problems we face as research scientists. Mr. Madson’s presentation of our current understanding of population cycles in greater sage-grouse was oversimplified and represents a significant mischaracterization and misunderstanding of current literature. I began to review the article line by line, isolating each premise to assess the cogency of the arguments presented (as I would the dozens of peer-reviewed articles I review every year). However, I realized quickly that this approach would not make for good reading. So, here I present three examples of the most fallacious claims:

(1) “Over the last 70 years, the notion that sage-grouse populations have a 10-year cycle has been accepted with remarkably little technical rigor.

The eminent scientist J.B. Haldane once wrote there are four stages of scientific acceptance.

  1. This is worthless nonsense;
  2. This is an interesting, but perverse, point of view;
  3. This is true, but quite unimportant;
  4. I always said so.

I thought that in the over 10 years since I published my first analyses of population cycles in sage-grouse in Wyoming, we had moved (at least) to step three in Haldane’s stages. When I submitted my first publications on population cycling in sage-grouse I was met with dismissive reviews from other professionals in the field. Several reviewers were convinced that it was worthless nonsense while others claimed that what I presented was already known. Since then, I have published six peer-reviewed publications on the topic in top journals that have received over 100 citations in the peer-reviewed literature. The modelling approaches presented in those manuscripts range from basic statistics to more sophisticated approaches including nonlinear modelling, wavelet analysis, and approximate Bayesian computation. Whether you are familiar with the approaches or not, I assure you they are statistically rigorous and represent some of the most technically advanced approaches to describing population trends. This research has been reviewed and critiqued in detail by many experts in the field before publication and I have presented the research at many professional conferences. The “notion” of population cycles in sage-grouse has been challenged at every step by the broader research community to ensure that we can collectively address the complexities of population dynamics across sage-grouse populations. I admit that some of the modelling applications are complex — it is my job to develop and implement unique approaches — and may be challenging to interpret. However, these types of population trend models are used by avian monitoring organizations around the world.

(2) “The “peaks” in sage-grouse counts that supposedly indicate a cyclic high can be anemic, so anemic, in fact, as to raise the question of whether they’re real peaks or just blips in the data, and the counts are often “smoothed” statistically to get rid of inconvenient year-to-year changes that might not be consistent with the expected pattern of the cycle.”

I appreciate the emotive impact of the word “anemic” in this description. It is evocative, but unfortunately, not very precise. I am a writer, but I am a scientist first, so I will aim for precision. Depending on the population in Wyoming, the difference between the low point in a cycle (i.e., nadir) and the high point (i.e., peak) can represent a 20% to 80% change in the population index. If the peak in consideration has not reached the same magnitude as a prior peak, we can quantify the disparity in terms of percent change in the population index (negative) along with the appropriate confidence intervals. These types of changes over relatively short time frames certainly do not seem anemic. Furthermore, cyclical does not imply that all the peaks and all the nadirs are of the same magnitude. For those populations where the model results support cycling, there is often a trending decline in population abundance. This negative trend could be captured even more simply with a linear model, and while that would simplify interpretation, it would miss the complexity of the population cycles that actually occur. It seems abundantly clear that anyone concerned with the conservation or management of a species should be concerned with populations trending toward lesser abundance, and would want to know where in the cycle the population has been in the past and may be in the future.

(3) “Three of the most recent attempts to analyze sage-grouse populations reach startlingly different conclusions.

The three studies used similar data sets and this statement would be somewhat remarkable if the three studies were asking the same questions. But they were not asking the same questions. There are two related but different components when addressing long-term trends in sage-grouse (and all wildlife populations). One is to address the long-term, overall trends. As noted by Mr. Madson, this approach was applied to excellent effect in the work of Dr. Garton and colleagues in their assessment of long-term trends. I will oversimplify, but essentially Garton et al. were interested in long-term trends and therefore fit linear models to data to estimate long-term trends. I have also focused on long-term trends in Wyoming along with coauthors. In that paper we estimated the long-term decline in Wyoming sage-grouse using a combination of nonlinear modelling and change point analysis. Our results indicated a 54% decline with a 95% confidence interval of -64% to -41% from the peak in 1968 to the peak in 2006. Clearly a declining trend. On this we all agree. 

The other important aspect of a trend is the variation around that trend, which in Wyoming, at the statewide level, has historically been cyclic. Oftentimes, when we conduct these types of analyses we use statistical techniques to specifically de-trend the data. That means we effectively remove the overall declining trend because we specifically want to isolate the variation around the trend. These results are clearly presented in my work. (An interesting side note is that in this paper we found sage-grouse cycles highly correlated with rabbit trends in Wyoming.) 

The USGS publication cited by Mr. Madson and led by Dr. Pete Coates is an excellent example of how science moves forward. We know that sage-grouse populations are generally declining across the species’ range, and from my research on population cycles, we know there is cycling in some populations. Coates and coauthors have addressed these issues by explicitly modelling the low points (i.e., nadirs) of population trends across the range. This appears to be an eloquent approach to addressing long-term trends — highlighting the most concerning point in a cycle: the point at which a population is at its least — while concurrently addressing the variation around that trend as demonstrated in much of my research I have discussed here.

I have multiple other concerns. For example, Mr. Madson argues “The thing that makes a cycle a cycle, the one characteristic that sets it apart from other kinds of change, is that a series of events leads eventually back to a starting point.” For starters, this statement is patently false in both wildlife ecology and statistics. Perpetuating this myth is harmful to the public’s understanding of ecology and basic science. Furthermore, even if the statement was true, choosing a “starting point” that is ecologically relevant and statistically rigorous isn’t easy. There are dramatic differences in the sampling effort and approach for sage-grouse from the 1960s until today that will fundamentally influence how we understand these systems.

Clearly Mr. Madson is concerned with dishonest actors relying on the existence of population cycles in some populations as an excuse to delay action with the false assumption that all cycles return to their origin. I share this concern and I am always clear regarding the uncertainties in my analyses and the importance of spatial and temporal variation. There are many important management implications for understanding population cycles including the obvious one of trend assessment, but it is also relevant to study design, adaptive management, impact assessment, and others that are detailed in my relevant publications.

Relatedly (and in conclusion), Mr. Madson claims “The concept of the cycle does nothing to help us solve the fundamental problems facing sage grouse in the West.” Sage-grouse are a species of conservation concern. I would argue that one of the “fundamental problems” facing the species is the accurate description of the variation in population abundance. We must endeavor to understand why populations change. If we ignore populations’ cycles — where they exist — we are engaging in willful ignorance. Ecology is complex. Sometimes the answers will also be complex. But that does not mean they are wrong and should be dismissed because they make management and interpretation difficult, or even if the answers may be misused.

Finally, I take some personal affront with Mr. Madson dismissing the thoughtful research efforts my coauthors and I have painstakingly undertaken as a “comforting myth.” If Mr. Madson has data or analyses, or even an informed critique of the methods applied in my manuscripts, I would be happy to hear them. Otherwise, as a scientist and critical thinker, I have to rely on the data, analyses, and conclusions presented in rigorously reviewed and published manuscripts. I encourage others to do the same.

Brad Fedy

Dr. Brad Fedy is an associate professor of wildlife ecology at the University of Waterloo, Canada. He has been studying greater sage-grouse population ecology, habitat use and genetics for over 15 years.

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  1. Owl Creek update: I talked to 3 Owl Creek landowners about predator control tonight at the VFW and learned some more interesting observations. 1.) The USDA aerial coyote hunters were seen and heard shooting coyotes this morning, 2.) The other 3 landowners have experienced “meaningful” interaction with raccoons 3.) A third landowner commented about the number of feral cats on the Owl Creek bottom, 4.) There is a healthy flock of about 50 turkeys frequenting the bottom and pheasants have been seen on the county road.
    My concern is with the feral cats since they can form “cat colonies” and become very, very numerous. This area of the Owl Creek bottom has rural subdivisions and many small acreages – probably 200 people in a small rural area which means lots of cats. Talking to the locals, it seems that coyotes, raccoons and feral cats are a predator problem but no mention of skunks by anyone. The 3 abundant predators are fully capable of depressing the game bird population without predator control which is ongoing – even this morning.

  2. Some of the disagreement here has to do with definition: What constitutes a cycle in a wildlife population? I find the quote I offered from Cole in my original essay to be insightful: If a cycle doesn’t have to have a set length, if it doesn’t have to return to some original point, then almost any population that fluctuates can be said to cycle. I wonder what use the concept of “cycle” has if it doesn’t need to fit either of these criteria. I respect the fact that Rowe and Fedy reported that four out of the fifteen sage grouse populations they analyzed did not, in fact, show evidence of cyclic behavior, that several other of these populations ceased to show cyclic behavior after the drought of the 1990s, and that the duration of the remaining “cycles” had shortened by almost fifty percent by the end of the period being analyzed. At a rational level, I continue to challenge the notion that fluctuations of such shifting character can be called cycles. As I say, this isn’t a critique of statistical approach; it’s is a matter of definition of the term “cycle,” and, from a purely academic point of view, I welcome discussion on that definition. From a practical point of view, however, I maintain that the acceptance of the idea that populations of greater sage grouse actually cycle influences management decisions in a way that is likely to be dangerous to the species in the future. All the climate modeling for the area in which sage grouse persist strongly suggest that droughts will be more frequent and severe in the future. We can’t change the weather over the next fifty years, but we certainly can be far more aggressive in our efforts to improve remaining sagebrush habitats so that surviving sage grouse populations can better withstand inimical weather patterns. It’s conceivable that populations of sage grouse and other Great Basin species respond to changing precipitation patterns driven by the ENSO, but modeling indicates that historical patterns of precipitation will be changing in a way that will not benefit native grouse or many other species. The ongoing reliance on the idea of a cycle in sage grouse numbers allows us to delay serious, landscape-scale habitat management efforts in the expectation that the birds will “come back” on their own as part of the cycle. It tends to shift public attention from the low points in population fluctuations to the high points. If we intend to retain this species in the wild, none of these attitudes is helpful. I believe I made almost
    all these points in my initial essay, and I have little more to add. I guess that leaves the ball in my court, where I am happy to let it remain.

  3. Chris Pfister: With respect to your statement that “sage grouse literally blackened the sky when the settlers came west.” This phenomenon does occur and I have personally witnessed it several times time and fully understand the dynamics of the game bird population which caused it. It occurs when habitat is abundant and predator populations are minimal. In my case, I grew up in the legendary pheasant hunting area of eastern South Dakota when weeds had completely taken over eastern South Dakota – before herbicides became widely used. The pheasants were so thick that they did black out the sky on occasion. Why?? Red fox were the apex predator and missing from the predator mix were coyotes, bobcats, eagles, ravens, crows, almost no hawks and falcons – MINIMAL PREDATORS!!! This was in the 1950s.
    Now fast forward to Wyoming today and add in COYOTES, bobcats, eagles, hawks falcons, ravens and crows to the predator mix and the dynamics of the sage grouse versus predator equation completely changes – and in addition add in sylvatic plague as an introduced disease. Totally different situation. However, observations by the settlers in the 1800s document a different situation in Wyoming – one in which the predators did not have the advantage – their populations were greatly reduced compared to todays predator mix.
    The dynamics in present day Wyoming again completely change in a predator less scenario such as I observed in 1993-2000 in Niobrara County – the game bird populations recovered and exploded in the 5th year after the sylvatic plague outbreak. VIRTUALLY NO PREDATORS!!!
    Bottom line is that I know what I’m talking about because I have personally witnessed these extremes in the sage grouse versus predator equation. I understand the dynamics. Have you ever met another person that was witnessed these dynamics on a first hand basis?

  4. Additional information on predator control: I called one of the farmers on Owl Creek tonight that has been involved in predator control in order to benefit pheasants. He confirmed they have taken 240 raccoons in the last 3 years on his place and the next door place. However, he mentioned that another neighbor supports feral cats; and that, the feral cats are having a huge impact on game bird populations. This activity by the landowners is supplemented by the local predator control board – who might be using poison eggs – and the USDA aerial coyote hunters. Its very time consuming and expensive to remove the predators that are predating on pheasants and sage grouse but that’s whats necessary to protect the game birds. Almost no one knows this, but the Weed and Pest Act of 1973 has a provision requiring control of the designated pests in Wyoming, and if the property owner doesn’t bring them under control, they can actually be charged and tried by jury for failure to control pests and noxious weeds. This is rarely done though and is a last measure no one wants to use – I do know of one case in Park County concerning a noxious weed which went to trial. These are the people that are producing tangible results for protecting our sage grouse chicks – its called PREDATOR CONTROL and it is an established way of life in Wyoming.

  5. I had an interesting conversation at lunch with one of our irrigators on Owl Creek. He said their pheasant numbers were way down; however, one of his neighbors had trapped over 30 raccoons and another over 60 raccoons on their bottom lands. In addition, the USDA aerial coyote control flyers have been shooting dozens of coyotes from the air in the vicinity of his place. This is irrigated bottom land with lots of cover provided by trees, wetlands created by irrigation water return ditches and roughage. Our local predator control board has been very active as has the USDA. Without intense predator control ( raptors excluded ) our game bird populations would be miserable. This predator control activity is the single most effective method of benefiting sage grouse in Wyoming and will result in an increase in the survivability of chicks. Ferral cats, barn cats and ranch cats can also have a significant impact on game bird populations and rats of course – its common for a momma cat to bring a rat, pheasant or grouse home to her kittens every day – I remember one momma cat that had about 15 dead rats all piled up for her kittens – the same can happen with game birds. Anyway, our predator control board and USDA are actually involved in predator control as a means of protecting our game birds. If you want to know whats really going on in Wyoming ask the farmers and ranchers living on the land not the academists.

  6. We need to concentrate on the CAUSE of the sage grouse population decline in Wyoming not on analyzing the EFFECT to the 9th degree with sophisticated modelling. Madsen’s article correctly identifies the main issue here which is the dismal survival of sage grouse chicks – 0.8 chicks per hen. Sage grouse hens normally lay 6-9 eggs per year for an average of about 7.5 eggs. Only 0.8 survive through the brood rearing season. Its my opinion, that they are either predated upon in the nest ( nest failure ) or predated upon after hatching. That is, a combination of red fox, coyotes, badgers, skunks, eagles, hawks, falcons, bobcats, ferral cats, crows, and ravens have a cumulative effect on chick survivability and that is where we need to concentrate our research. Lets get back to the basics of why the chicks are not surviving – the CAUSE of the problem.

    1. P.S. Please add: weasels, mink, raccoons and man to the list or predators affecting our sage grouse numbers. a chick doesn’t have a chance.

    2. Lee, with all due respect, the gigantic hole in your argument is the fact that sage grouse literally “darkened the sky” with their huge flocks when the first settlers came west. Back then there was no predator control, obviously. So what’s the difference between then and now? Us. I get tired of the argument it’s “the predators”! How do you explain that they seem to be thriving when there is less and less food because they are wiping out pretty much everything edible, according to you. As an aside, when out and about, I run into a lot more “recreational ” trappers then ever before, new people to the state. Haven’t run into a bobcat or badger in quite a while…

      1. Chris: I actually had opportunity to live during a complete sylvatic plague cycle and witnessed the remarkable explosion in game bird populations in the 4th-5th years after the outbreak; that is, during the years when there were almost NO predators left in the plague area. If researchers would explore this amazing phenomena like I did, they would find the same results. Where else can you study game bird populations in a predatorless scenario??? How many other Wyoming residents have personally witnessed this phenomena?? Not many and certainly none living in cities. This happened in 1993 to 2000 on Lance Creek/Cheyenne river in Niobrara County. Those of us that support a predator scenario had to put up with nothing but habitat, habitat, habitat for years – and, you habitat proponents have had your way for too many years without producing significant results in spite of tens of millions of dollars being spent on habitat improvement. Its time for the predator proponents to try to improve our sage grouse populations – you’ve had your chance and its been mostly failure. Show me the results you habitat proponents have attained – if any.

  7. I don’t see any mention or concern in Fedy’s article about the “precautionary principle” that is important to most concerned with preserving threatened species. His approach comforts the industries that are reducing sage grouse habitat–they’ll wait until they’re nearly extinct before they take action.

  8. Thank you, Dr. Fedy! This is the kind of respectful discourse that Wyofile allows–something we as a state, nation and world desperately need.