Interview with John Burch:

ES: Thanks for speaking with Earth and Sky. Can you give me some background information about these “new GPS collars”:http://www.nps.gov/yuch/Expanded/key_resources/wolf_study/wolf_study.htm being used to monitor wolves in the Yukon Charley National Preserve?

JB: The real idea behind it is to get more information, or more locations of where the wolves are traveling and spend less money doing it. That’s the real focus of using these GPS collars. And I kind of indicate that they’re new, but GPS collars have been around for sometime. But the big difference with these collars is that they’ll collect the GPS coordinates, they’ll get a fix of where the animal is, and it stores those on board, which is what the older collars did. The difference is that these collars will then transmit those locations over a different satellite system, and I’ll get them as an email message on my computer. So I don’t have to recover the collar, meaning having to recapture the wolf or wait till the wolf dies and pick up the collar to get all the data or locations back. So it’s a very innovative technology that companies come up with to get the information much more easily and frequently. It’s not as big a risk.

ES: How do these things work?

JB: The radio collars we’re putting in now will download their GPS locations through the ARGOS satellite system. We’ll get them as an email message, which is a very different thing. Another thing is that they will last much longer, the batteries will last for over three years. The way we have these collars programmed, I’ll get a location on each wolf, each day. And then they will download six of those locations once a week. And so once a week I get an email message, and I can run it through some software and get a location, run a map, and find out where the wolves were the previous six days. People have been radio collaring wolves for 30 years or more, but the conventional method of studying wolf populations with radio telemetry was with we’re calling conventional radio collars, where you would capture a wolf, put a radio collar on it, and the only way you would learn anything would be to go out on an airplane and radio track everything in and home in on the wolves, find the wolf, count them, and then record their location on a map. These new GPS – their limitation is that they only give us half of the information. We get very good information about where the wolves travel, their size and where their home ranges are. But we don’t have any idea about how many wolves are traveling with this radio collared wolf. So we still have to fly, and find them, and radio track them to get counts on the wolves. But it greatly improves our ability to estimate their home ranges and spend a lot less money doing it. And that money is saved because we’re not flying nearly as often.

ES: Can you give me a run-down on when the project began, when will it end, and who’s involved?

JB: The project started in 1993. And the reasoning why the project started, and why it’s still going, has evolved over time. The project started as more of a pure research project, trying to calculate predation rates of wolves on caribou, moose, and sheep in Yukon Charley. So the whole project focuses on a predator-prey relationship between wolves and their prey. And the prey in Yukon-Charley are moose, caribou, and dall sheep. And most of the focus of the project has been on moose and caribou, because we’re finding that the wolves aren’t really preying that much on dall sheep, at least in that area. Then the project evolved, where the State of Alaska had proposed some wolf control just outside the boundaries of Yukon-Charley. And the Park Service was in negotiations with the State of Alaska, other groups trying to find ways in which the wolves in Yukon-Charley wouldn’t be subjected to the control actions of the state, and the state was trying to reduce wolf populations in the area, kind of in an experimental way, by sterilizing the wolves, or two of the wolves, and moving the rest of them out. So it was sort of a non-lethal method. What the Park Service wanted to do was identify the wolves in Yukon-Charley, the wolves that lived primarily within Yukon-Charley, and have them not be sterilized or moved out of the area. And that ended up being quite successful. That program went on throughout 2001 and since then has ended. So then the project now has further evolved to try to continue to monitor the wolf population in Yukon-Charley relative to these sterilized pairs of wolves that are surrounding Yukon-Charley, as well as how the wolf population is responding to an increase in caribou herd. The forty-mile caribou herd has been growing, oh from about 20,000 caribou to about 40,000-45,000 caribou in the last 6-7 years. So the focus of the project has evolved over time, but it’s had this same general idea behind it.

ES: Can you tell me a little bit more about the relationship that wolves have with the forty-mile caribou herd?

JB: Well, yes, there was great interest in the forty-mile caribou herd over time – it has been for over decades. And the whole idea revolves around what role wolves – or bear – predation play in regulating ungulate population such as caribou, or moose in Alaska. And, there’s a lot of controversy around it, how important wolf predation is on calves, and wolf predation on adults, really contributes to limiting that population. The viewpoints range from, wolf and bear predation are the primary limiting factors. It’s unquestionable, and if we reduce predation on this herd, say the forty-mile caribou herd, the population will increase. But other viewpoints are that it isn’t true at all; that wolves don’t affect or limit prey populations at all. Most viewpoints are somewhere in between, I think. Where, certainly, wolf and bear predation on caribou, or most herds, has a significant impact, but I think that my personal view is that the role of the importance of predation in limiting the populations of caribou or moose is very variable. Some years, in some places, it’s quite important. Whereas, in other years and other places, it’s not as important, and other variable might become much more important, such as snow depth over the winter, or the nutrition of a caribou herd. And I think the problem is that no one has really been able to develop a program or a project to focus in on these changing variables and these changing roles in limiting ungulate populations. It would be a quite difficult undertaking. And the real difficulty is getting support and funding for it to go for a very long time. We’d need to monitor all these variables for long periods of time – maybe decades of time – to allow these populations of wildlife, both their predators, the wolves and the bears, and their prey, to change, increasing and decreasing over large periods of time. The whole time, while we are monitoring these variables, such as weather conditions, forage quality and predation rates, and overall population size changes of both the wolves, the bears, the caribou, and moose. And if we can do something about that, I think it would really help answer a controversial question of, “how necessary is something like wolf control.” Or we’d be able to predict something like, “yes, it is population of moose or caribou at this time and place is being limited by predation, and therefore something like wolf control might actually help. On the other side, we might be able to say the opposite. Say, in this case, in this date and time, it’s not really predation. It’s more of the caribou or moose’s food, their forage quantity or quality of it is really limiting. Or there’s a series of bad winters with deep snow that allows them to escape predators or get enough to eat. Things like that. And it really can be kind of subtle, where even just small amounts of changes in average body weights of animals over time can be a significant player in the overall fitness of the animals of the herd and their ability to escape predation, or their ability to have calves survive, till they’re recruited into the population and have more of their own calves – that kind of thing. So it gets real sticky and tricky, where the things that we’re trying to look at and monitor are quite subtle. They’re not real obvious. You can’t just say that the caribou are just old and sick that the wolves are killing. It’s not that easy or obvious. It’s much subtler. Changes in their physiology and their health can really affect it. The real challenge is going to be trying to get funding and a focus on these kinds of things to try and answer the question of why do wildlife populations change. And it’s ironic, that all of this studying that’s been goin on in Alaska, we still can’t really answer that question, of why does the forty-mile caribou population change. We know it changes, we can monitor it’s change. But we don’t know why. We don’t know exactly why. We can guess. And some people think they know why. But when you try to push them and really focus down on it, it’s difficult for them to prove it. I think someplace in Alaska needs to have a very good focus study on those kinds of things, to really try and answer that question.

ES:

JB: Yeah, hopefully it will. What this particular aspect of the project will be is to better calculate how many wolves are in the area. And that’s generally – we talk about wolf densities rather than total number of wolves, since the area that the wolves use can change quite a bit. Home ranges can vary in size. It gets a little bit sticky just to talk about total numbers of wolves. So our solution to that is to talk about a density of wolves. And that density is often, so many wolves per thousand square kilometers. So that’s kind of how scientists in the field have decided to compare different populations of wolves to one another. These GPS collars will allow us to better estimate the home ranges of wolves, and much better. We’ll be getting possibly ten times more data, or ten times more locations per year on each wolf pack than we did using conventional radio telemetry. And what we find is that the more locations you get on a wolf, say focus on one wolf pack. The more locations you get in a year, the larger their home range becomes. And it’s not that the wolves are doing anything different, it’s our sampling of where they are through time. When we’re out there trying to do it with conventional radio collars from airplanes, we’re lucky if we can get 30 or 40 locations a year. With GPS collars, we’ll be able to get somewhere in the neighborhood of 300 locations a year. And what I’m predicting we’re going to find is that we’re going to learn that wolves travel over larger areas than we originally predicted, and that the wolf densities are not as high as we think they are because the area that these wolves use is bigger than we think it is. So if you take a count of wolves, and divide it by the amount of area that they use, if the area gets bigger and bigger, the density is going to get smaller. And so, what these new GPS are going to allow us to do is more accurately estimate how many wolves are in a given area, and how that population of wolves is changing over time. Is the population increasing, or decreasing over time?

ES:

JB: Oh gosh yes, and in fact these wolves are really – there’s a continuous population of wolves pretty much throughout Alaska. And you can think of it as one home range of wolves adjacent to another one. So this is just a little like a cookie cutter, in and around Yukon-Charley. There are wolves throughout the whole area. And, that actually kind of presents part of the problem, saying, “Okay, how many wolves are there in Yukon-Charley?” And, the answer that people are looking for – it’s about 50 wolves. At any given time there’s about 50 wolves within Yukon-Charley. The problem is that their home ranges of the individual packs, obviously they don’t know where the boundary of the park by any stretch of the imagination. The area surrounding Yukon-Charley is very wild and pristine country as well. And we have some political boundaries that the wolves have no idea about. So that their individual home ranges span this boundary. And in fact, there isn’t a single wolf pack in the area that is completely enclosed in Yukon-Charley preserve. They all get outside of the boundary of the preserve to some level, some more than others. And some, they’re just a small portion of their time and home ranges within the preserve. But the answer that people want, there’s about 45-50 wolves within Yukon-Charley right now. The interesting thing is, that if you just added up the number of wolves in all those packs, which is about 11 wolf packs, you’d get about 90 wolves – but you’d end up with an area that’s much larger than Yukon-Charley itself, if you just added up the home ranges and the number of wolves in each pack, being in a much larger area. So that’s kind of why people that study wolves tend to want to use wolf density to compare population to another. Because different for different places, the wolves have different sizes of home ranges, and they have different numbers of wolves within their packs. And so it gets difficult to compare, say how many wolves there are in Yukon-Charley versus how many wolves there are in “Denali National Park”:http://www.nps.gov/dena/, or how many wolves there are in “Gates of the Arctic”:http://www.nps.gov/gaar/. It’s much more educational I guess, or easier to compare consistently, the wolf density of one place to another. So the wolf density of Yukon-Charley is four to five wolves per thousand square kilometers. That’s sort of the unit of measure that we use.

ES:

JB: Yeah, most of the wolves in the area definitely travel in packs, and pack sizes range from about five or six wolves to 12 to 13 wolves. And it varies from year to year. And these packs generally are made up of a breeding pair, which are often called the alpha pair – the alpha male and the alpha female. And they’re usually the two wolves that breed, and the one female has pups. And the pack is generally made up of this alpha pair and their offspring for the last couple of years. Generally when a wolf gets to be two or three years old, it’ll often disperse and leave its pack and travel hundreds of miles, looking for a mate and maybe another area that’s not currently occupied by a pack of wolves, and try to have their own pups, and set up shop, and have their own home range. It’s kind of a dangerous thing, because the wolves will often kill one another, particularly if a wolf is trespassing into another wolf’s home range. But, that’s kind of the general makeup into a pack of wolves, and how the populations work. The home ranges are somewhat territorial – there’s quite a bit of overlap between them, and the wolves often are territorial, not just in space, but in time. So that one pack may trespass into another one’s home range, but in an area that that pack currently isn’t using right now. And so, when you look at all the locations that we get from these GPS collars or from conventional radio telemetry, the home ranges of these animals overlap a fair amount, but on the same side of things they’re also fairly distinct. So there’s overlap around the edges, but there’s distinct individual home ranges of wolves. So that’s what most of the population is made up of. But there’s also another element of these dispersing wolves, which we call lone wolves. And these wolves will often disperse from packs and travel widely through the area, again looking for another wolf of the opposite sex to settle down and have their own pups and start the beginnings of a new pack. That’s the way populations can increase or decrease, by increasing the number of packs in the area, as well as the number of wolves in each pack.

ES:

JB: Well that’s actually something that we try and do as best we can, and it comes down to economics. The radio collars are kind of expensive, so we focus our attention on that alpha pair. There’s the alpha male and the alpha female, and we try and pick those out of the group and catch those animals to put the radio collars on them. And there’s really two main reasons for doing that. One is that they’re much less likely to leave, and disperse, and take off hundred of miles away with your radio collar. The other reason is that they’re the ones that are making the decisions about where the pack goes, where they hunt, what they do, and any other pups and wolves follow suit. So they’re kind of the leaders of the group. And they’re the ones that we really want to follow.

ES:

JB: Yes, really it’s pretty simple. We have to capture the wolves to put the radio collars on them. And that’s done with both fixed wing aircraft, which is like a supercub, a small airplane with one pilot and one passenger. And then we use a helicopter to actually do the capturing. And, so what will typically happen, we’ll fly out with a supercub, and find the track of a pack of wolves in the snow. Then, from the airplane, determine which way those wolves are traveling in the snow, and follow their tracks until we catch up with them in the airplane. And when we catch up with the wolves and find them, the airplane will radio to the helicopter to come in, and we’ll be set up there with a dart rifle and darts and drugs, and fly in close and try to pick out the wolf we want and dart it with a dart that has drugs in it. And the animal will essentially go to sleep, and we’ll land the helicopter as close to the animal and walk up to it, and do a quite a wide variety of things to the animal. Mostly, the primary objective is to put the radio collar on the wolves. But we’ll also take a blood sample. We’re doing some genetic studies on the blood and tissue that we get from the wolves. And we do all a variety of measurements and weigh them and that kind of thing. And the wolves are released, and we move on to the next pack. And sometimes I often try to catch two wolves in each pack. It’s nice if you can get both the alpha male and the alpha female, but sometimes it doesn’t work out that well. But it’s nice to have two collars in each pack. That way if one collared animal does die or disperse, you still have that radio collar in the group, so you can then go back and catch another wolf, and keep at least two animals with collars in each pack. So that’s kind of how we catch the wolves. And that’s done maybe one week in the fall, like November, right about now. I just finished catching wolves in Denali National Park last week. And then we’ll do it again probably in the spring, like in March when there’s lots of snow and the daylight is coming back, and it’s more efficient to do the flying and finding wolves. So we’ll catch wolves about twice a year, and maybe for a week we’ll be out in the airplane and the helicopter doing that. And then the rest of the year we’re radio tracking with an airplane. And what that entails is just flying out, usually it’s the same airplane and pilot as we used for the capture, and we’ve got antennas on the plane and a receiver. And we have all the frequencies for the wolves that we’ve captured. And, using that equipment we can home in on each one of those radio collars, have individual frequencies. And, you can actually home right in on them and start circling and see them from the airplane. Some of the time they’re going to be underneath a thick canopy of trees or something where you can’t see them very well, or they’ll be up in some high, rocky, mountainous areas where the snow is very windblown and mottled, and you can’t see them as well. But, for the most part, you hope to find them travelling single file down a river or all gathered around a moose that they’ve killed, or something like that, where you can get a good count on them. And then we also keep track of where they are on a map. So there’s two main pieces of information we get – how many wolves are there and where they are on the map. So that’s kind of the routine.

[Tape II]
ES:

JB: Well, in Yukon-Charley, there are about 11 packs of wolves. And there are two collars on each pack right now. So we’ve got about 22 radio-collared wolves in 11 packs of wolves out there.

ES:

JB: Yeah, as you remember – it does vary from year to year a lot, as far as how many wolves we have collared, but also how many wolves there are. And, so where there might be 40-50 wolves in Yukon-Charley at any given time, remember that these 11 packs incorporate 90-100 wolves. So, they travel widely outside of Yukon-Charley.

ES:

JB: Okay, well the project started in 1993 as a whole. But we’ve just started using the GPS collars in the last year. So it’s kind of a new technology to be using right now. The project will continue for another three years, possibly longer if we can get the funding for it. But right now, the project will last for another three years. So it should go through to 2006.

ES:

JB: Well, actually, the thing that immediately comes to my mind is wolves preying on dall sheep – they’re the white sheep that live in the mountains. And what was very surprising in Yukon-Charley, was how few sheep the wolves were killing. Earlier, before this study began, we had assumed that wolf predation was probably a pretty important aspect of limiting the sheep population in the area. But now, after several years of study, we rarely find wolves traveling where the sheep live in the mountains, and rarely find them where the wolves have killed one of the sheep. Contrasting that Denali National Park, where we frequently find wolves killing sheep. Now the question that comes to my mind is why. There’s far fewer sheep in Yukon-Charley than there is in Denali National Park. Now that may be the answer, but the real answer is that we don’t know for sure. And I’m not saying that wolves don’t kill sheep in Yukon-Charley. But they kill them very infrequently, when compared to radio tracking wolves in Denali National Park. So odds are, the reason wolves don’t kill sheep more frequently in Yukon-Charley is that there aren’t enough sheep in the area to make it worth their while to hunt and kill sheep. They definitely kill one once in a while opportunistically, but their primary focus is on hunting and killing caribou and moose rather than sheep. But I was very surprised to learn that – how infrequently we would find wolves killing dall sheep.

ES:

JB: How long wolves have been in the area, you could just say Alaska in general I guess, but essentially – forever – or since the last ice age, there’s been wolves here. And, in all likelihood, the wolf populations in Alaska are doing very well. They’re under no threat, as far as wolves becoming extirpated in Alaska or anything, they’re doing very well, and there’s no reason to assume that wolves won’t be travelling as they have for thousands of years in the past and thousands of years in the future. They’re going as they have been for a long time.

ES:

JB: Well, to some level, yes. And you have to understand that Alaska is a big place. So some caribou herds in Alaska are doing real well, and others aren’t. So a big question in many people’s minds is – why? Why does one decline, while another herd is increasing? And what role do wolves play in that decline? And will wolf control help turn the declining population around? Will wolf control help that population increase? And when I say wolf control – there’s a variety of ways – but it’s reducing the wolf population dramatically by 80% or more, and the idea is to do it in a focused area where a caribou herd calves most of the time, or a moose population is low number, to help, primarily to help increase calf survival and recruitment into the population. But it will also help overall survival of the adults as well. So, the question is, why does it seem to be such an important factor in some places but not in others? And, the whole focus of the work in Yukon-Charley revolves around a specific herd – “the Forty-Mile Caribou Herd”:http://www.nps.gov/yuch/pphtml/animals.html – and the history of that herd is quite colorful. They had possible as many as 500,000 animals, although we don’t’ really know if that’s true, back in the 1930s, back in the days of “Adolph Murrie”:http://www.muriecenter.org/family.htm, he was doing some “studies throughout Alaska”:http://www.cr.nps.gov/history/online_books/fauna7/fauna3a.htm. And the population crashed to maybe 60,000 animals in the 1970s and all the way down to maybe as low as six or seven thousand animals, total in the forty-Mile Caribou Herd, back in the early 1980s. And so everybody’s wondering, what happened? Why was there such an enormous decrease in the numbers of forty-Mile caribou? And, is there anything we can do about it? So there was a whole forty-Mile team that was formed to try to decide on management decisions as to what to do to try to increase the forty-Mile Caribou herd, and one of the “things they decided”: was to try to reduce wolf predation on calves and adults by decreasing the population of wolves by about 80%, and to try to allow that Forty-Mile Caribou Herd to increase for a few years, and try to try and escape this predation, so that the numbers of caribou gets high enough so that the wolves couldn’t limit their population, or hold their population at a low number. That’s the idea behind the whole “study”:http://www.nps.gov/yuch/Expanded/key_resources/2002_wolf_report/2002wolfreport.htm we’re involved in, and the concern over the Forty-Mile Caribou Herd. But the problem is, nobody really knows for sure what’s right and what isn’t. We never really were positive that it was wolf predation, or wolves and their predation that was really limiting that herd. I mean, it might have been, or it might have been at some time in the past, but we didn’t know for sure. That’s kind of where I was not as fully behind it as I could have been. But, there’s no doubt that wolves and bears kill lots of caribou calves, and the wolf control that the state did there probably helped, particularly in some years where we had some heavy snow and caribou would have been particularly vulnerable to wolf predation. But there are some things about it that make it not quite so sure. One of the things is that the caribou population, the Forty-Mile Caribou Herd was already starting to recover, it was starting to grow. We were up to about 20,000-22,000 animals from a low of about 6000-7000 before they started to do this wolf control, the most recent version. So, my question is, what would have happened had wolf control hadn’t happened – we hadn’t done any kind of wolf control at all. Would that population have continued to increase, and close to where it is now – the current estimate is about 40,000 to 45,000 animals. So it appears to be increasing, there’s a low age of calves, which is good. It’s an age structure where there’s lots of young cows being recruited into the population, and that will then have their own calves. So the future looks quite bright for the Forty-Mile Caribou Herd right now. I guess I wish we could have learned more about why that population is increasing, and what specific role wolf and bear predation played in that whole dynamic. And then, what role the other variables played too, like the nutrition of the animals, and the snow depth, and some people are speculating that summer precipitation, rainfall, could actually affect the nutrition of caribou by making lichens more – the caribou eat lichens as their primary food – and wet lichens are more digestible than dry lichens is the theory, or an idea. No one’s studied that heavily, no one’s tested it heavily, that I know of anyway. But it’s another idea out there – there could be other variables and other reasons that cause caribou populations or moose populations to increase or decrease, that we’re really not focusing on. And it’s really easy to jump to the conclusion of wolf or bear predation being the primary cause of a population either declining or not growing. And, my personal feeling is that it’s probably more complicated than that. And I wish we could get a study to really focus on it for a long time.

ES:

JB: I guess I’m not sure what you mean. We can have the success of how many radio collared wolves we have, and how many radio collared packs we have, and how long they’re living and that kind of thing. But I guess the success of the project really comes in to play when management decisions are made based on the information that we collect, rather than political motivations or something. I think that would be the ultimate success of a research project on a wolf population or a caribou population, or anything – when that information is used, and used well to make good, sound management decisions about harvest of caribou, or wolf trapping regulations or something like that. I think that would be the ultimate measure of success on a project like this one.

ES:

JB: Well, no, I think we’re just trying to keep a study going that’s been underway now for about ten years, and we’re really striving for a better way to do the same thing I guess – and that’s just to monitor the population over time and to detect trends, and whether the wolf population is increasing or decreasing, and how the caribou population is resounding, or vice-versa, how the wolf population is responding to an increase or decrease in the caribou population. And these GPS collars that we bring up once in a while now are really just a step in the whole process of trying to find better ways to studying these wildlife populations and trying to make strides to answering these larger, overall questions of why do wildlife populations change? I think I said earlier that we know that the populations do change, of say moose or caribou, but we still – even in this day and age – we really still don’t know why they change. What collection of variable causes these populations to change? And, which ones are the most important? And how does that importance change over time, from one year to the next, and how does that importance change from one place to another? Maybe wolf predation is one of the most important variables causing population change in one place, but in another, the other side of Alaska or something, it could be winter severity or winter snowfall, or poor forage quality. Or there isn’t enough forage for the animal. For the caribou herd now the lichen ranges have been depleted by overgrazing, or something like that. So, I think that the best focus I could try to put people on to is trying to keep the question in mind of why the populations change rather than that we know that they’re changing. That would then help us in future better manage these populations of wildlife that are so important to people throughout Alaska, both for food, or just cultural identity, photography, you could come up with a lot of reasons why large mammal populations in Alaska and Canada are very important to people. Tourism is another one, another big moneymaker for Alaska. At any rate, for one reason or another, these animal populations, or wildlife populations are very important to people. And yet, we don’t know why these populations change.

ES:

JB: Well, actually, no – the ones from Yellowstone came from British Columbia, in Canada. Well, there was a specific reason for that. They wanted to introduce wolves that were used to preying on elk, because they knew that was going to be their primary prey in Yellowstone. And, there was a very healthy population of wolves in British Columbia that preyed on elk. And so that’s why they moved wolves from that area to Yellowstone rather than Alaska. There’s really no population of wolves that live on elk in Alaska at all. There’s hardly any elk, and what elk are here were actually introduced themselves, so there’s virtually no elk in Alaska. Caribou, moose, and sheep, are the three main species that live in Alaska.

JB: Right, now that’s a whole other story there. They’re getting those wolves I think from Northern Mexico and Southern Texas, and trying to raise them in captivity to keep the gene pool together as best they can, and then release them. So that’s a very different situation than Yellowstone.

The following person was interviewed for today’s program. Our thanks to:

John Burch
Wildlife Biologist
Yukon-Charley National Preserve
Gates of the Arctic National Preserve
Denali National Park
National Park Service
Fairbanks, AK