How Is Urbanization Affecting Mountain Lions?
July 13, 2010 11:27 a.m.
Researchers from the University of California Davis's Wildlife Health Center have been working to monitor mountain lions as they navigate a southern California landscape increasingly fragmented by roads, housing developments and the border. As the Puma Project enters its second decade, new data is revealing the challenges facing wildlife in the region.
Related Story: How Is Urbanization Affecting Mountain Lions?
MAUREEN CAVANAUGH (Host): I'm Maureen Cavanaugh. You're listening to These Days on KPBS. San Diego is a wildlife researcher's paradise. We have an abundance of different kinds of native species in our county, the most of any county in the U.S. But we are also a test case – case, that is, in how we are handling that diversity and our grades are mixed. One of the most interesting examples of the challenge of wildlife in a growing urban area, can be found in San Diego's mountain lion population. We’ll be talking about mountain lions and other species being tracked in our county with my guests. Dr. Winston Vickers is associate veterinarian at the UC Davis Wildlife Health Center and staff veterinarian for the Institute for Wildlife Studies. Dr. Vickers, welcome to These Days.
DR. WINSTON VICKERS (Associate Veterinarian, UC Davis Wildlife Health Center): Thank you.
CAVANAUGH: And Barry Martin is founder of the San Diego Tracking Team. Barry, good morning.
BARRY MARTIN (Founder, San Diego Tracking Team): Good morning.
CAVANAUGH: We’d like to invite our listeners to join the conversation. What kinds of wildlife do you usually see in your neighborhood? Have you seen deer or a grey fox lately? Have you ever encountered a mountain lion? Give us a call with your questions and your comments and your sightings. Our number is 1-888-895-5727, that’s 1-888-895-KPBS. Dr. Vickers, let me start with you and, if you could, tell us a little bit about the Puma Project.
DR. VICKERS: The Puma Project began in 2000, initially with the goal of assessing the impact of mountain lions on bighorn sheep in the Peninsular Range and in San Diego County. Those endangered bands of bighorns were of concern and continue to be of concern because of their numbers being relatively low and them being on the endangered species list. And questions were present as to how much impact mountain lions had on those populations. And over time, the project has expanded to encompass questions or examine questions relating to mountain lion health and disease, exposure to toxins, genetics, interactions with other species as well, such as deer, and with humans and movement across the landscape and how they interact with our rural residents as well as the urban edge.
CAVANAUGH: So the focus of the project kind of shifted from the bighorn sheep to the mountain lion.
DR. VICKERS: It has. It continues to include bighorns. We currently have at least one mountain lion that’s collared in bighorn habitat that we evaluate the prey relationships that he has with the deer and the bighorns, and we continue to attempt to capture additional lions in that area. But it has shifted and encompassed a lot of other questions.
CAVANAUGH: Let me just – just to be clear, are puma and cougar and mountain lion, are we talking about the same animal?
DR. VICKERS: We are. That’s a good question, and that is confusing to people sometimes. Puma, cougar, mountain lion, catamount, panther—in the case of the Florida mountain lion, they’re called Florida panthers—so they have traditionally had a lot of different names.
CAVANAUGH: And it’s just the same animal, it’s just what different people in different states call them.
DR. VICKERS: Yeah, it tends to be a regional phenomenon…
DR. VICKERS: …and sometimes they’ll have multiple names in one way or another. Even here, they’re probably called commonly by the three names: puma, cougar and mountain lion.
CAVANAUGH: Dr. Vickers, where do bighorn sheep live in San Diego County?
DR. VICKERS: In the Peninsular Range and the Jacumba Mountains of eastern San Diego County. Primarily Anza-Borrego State Park is a large area that hosts, you know, pretty substantial bighorn populations as well as conserved lands, Bureau of Land Management lands and so forth, national forest lands, to some degree, in the Peninsular Ranges.
CAVANAUGH: Now, what – Can you tell us, Dr. Vickers, what importance do mountain lions have to this region. Generally speaking, we are warned against – Basically they’re thought of as a danger for hikers and bikers. But in the ecology of San Diego County, what importance do they have?
DR. VICKERS: Mountain lions fill the niche of all the top predators, the larger predators and, in some areas, they would compete and also work with or compete with bears and wolves. But in Southern California, they’re the top predator, the only really large one. And so they primarily prey on deer and so they tend to interact with the deer population to help keep it in check and also have a regulatory effect on some of the middle-sized predators such as coyotes and even bobcats. They do also prey on those. And so they are part of the balance in that entire predator-prey chain, food chain, and they happen to be at the top on the mammal side.
CAVANAUGH: I’m speaking with Dr. Winston Vickers. He’s associate veterinarian with the UC Davis Wildlife Health Center. And Barry Martin, founder of the San Diego Tracking Team. And we are taking your calls about the kind of wildlife that you have seen in your neighborhood. 1-888-895-5727 is the number to call. Barry Martin, let me get you into the conversation. What is it about San Diego County that makes it an important area to protect in terms of wildlife conservation?
MARTIN: Well, San Diego County is the most biologically diverse county in the lower 48, and, you know, we’re just thrilled to live there. So are a lot of the different species that inhabit the area. Consequently, since everybody loves San Diego, we run into kind of a problem between the people that want to develop and the wildlife that have lived there for eons. So, obviously, it’s in our interest to try and accommodate both.
CAVANAUGH: Tell us about your group, the San Diego Tracking Team.
MARTIN: Well, it’s a group of concerned citizens and we like to – We pride ourselves on the fact that we pursue citizen science with using wildlife tracking as our basis for data collection. We have a training curriculum that people are required to go through if they wish to be survey leaders and it’s quite rigorous. It takes about a year, year and a half to two years, actually, once they get through the apprentice program. And we’re very concerned about the accuracy of the data, obviously, so it’s a pretty extensive training course and you come out the other end fairly knowledgeable on San Diego species.
CAVANAUGH: Now how would you actually go about the – a tracking project? I mean, where would you go and how do you count?
MARTIN: Well, the way it works with the San Diego Tracking Team is that we’ve identified various sensitive areas throughout the county that, you know, should be conserved, in our opinion, and then we’ve gotten plenty of cooperation for various open space preserve areas and there’s – these preserve areas are linked or at least we’re trying to maintain linkages. It’s well known that each habitat could be – to remain viable, must be linked with other habitats…
MARTIN: …for purposes of genetic diversity so what we do is our Tracking Team members go out every quarter and do surveys in these various different areas. We call them survey transects, and these transects, oh, we’ve got somewhere in the vicinity of 50 of those now and throughout the county and we’ve gotten quite a – We’ve got about 15 years of data accumulated and quite a few different research projects and several accomplishments to our credit in helping to conserve these corridors and open space areas.
CAVANAUGH: We are taking your calls about wildlife in San Diego, what you’ve seen, the kind of animals that perhaps are in your neighborhood from time to time. 1-888-895-5727, that’s 1-888-895-KPBS. Pat is calling us from Rolando. And good morning, Pat. Welcome to These Days.
PAT (Caller, Rolando): Yes, thanks for taking the call.
CAVANAUGH: Yes, how can we help you, Pat?
PAT: Well, I have a couple of questions sort of for myself and my students. I like to go up to Mt. Laguna with my little cocker spaniel and let him off the leash, but I remember years ago at Cuyamaca it was an issue, you know, with mountain lions stalking lone beings. And I hear that Laguna is getting – has like a whole group of mountain lions now, and I’m wondering if it’s safe to go up there. So kind of for myself, and also I teach new immigrants, adult immigrants from Iraq, Afghanistan, Somalia, and they live in, you know, inner city, east county. I’m trying to give them cheap recreational things to do to help them get out in nature but I certainly wouldn’t want to send them up there without the proper information about how to be safe.
CAVANAUGH: Well, thank you, Pat. And Dr. Vickers, what about Mt. Laguna and the safety of both dogs and people?
DR. VICKERS: Well, mountain lion – risk from mountain lions, speaking in sort of the big terms, is very low for any given hiker or any given person in the back country. California Fish & Game and virtually every expert I know recommends that people not go out by themselves, that two people together, or more, are much safer and much less likely to have a negative encounter with a mountain lion. Mountain lions generally want to stay away from us and the vast majority of encounters are fleeting glimpses as the mountain lion flees. However, occasionally, for whatever reason, a mountain lion and a human may come together on a trail and the mountain lion may not be so quick to flee or may exhibit behavior that concerns the human and it’s much better to have two people there. As to taking dogs, that – Certainly, letting dogs off leash in wild areas is not a good idea because they will chase and impact smaller wildlife even if they’re not putting themselves at direct risk. But, certainly, dogs have been taken by mountain lions. They’re much more interesting to the mountain lion than the person is as a prey species. They’re much, you know, closer to a coyote size or to normal prey for the lion, and so they don’t really distinguish between a dog and any other prey item of that size…
CAVANAUGH: Do you have any…
DR. VICKERS: …so it’s putting the dog at risk.
CAVANAUGH: Do you have any specific information as to whether or not there is a significant mountain lion population around Mt. Laguna?
DR. VICKERS: We have always – Any of the wild areas in San Diego County that have a combination of cover and deer are probably – probably host a mountain lion coming through every now and then. Mountain lions have very large territories so they don’t bunch up, they don’t go in groups, they’re solitary. They maintain territories as adults, so any given location will rarely have more than a couple of adult mountain lions that frequent it on a regular basis. They’re, you know, they have a little bit of overlap and so you could be in an overlap area. But generally, juveniles moving through trying to find territories and the resident adult is the extent of the population in any given place. But certainly the Lagunas are a great habitat and we have certainly found mountain lions there and could probably find sign of a mountain lion if we covered enough trails in that area today.
DR. VICKERS: So it’s an area – Anyone using the back country should be aware that mountain lions do use the back country, too.
CAVANAUGH: Daniel is calling from Clairemont. Good morning, Daniel. Welcome to These Days.
DANIEL (Caller, Clairemont): Thank you very much for the topic and your guests. My question is if there is mountain lions in the Cleveland Forest? And then also what construction projects and also fire does to a mountain lion and its region.
CAVANAUGH: Thank you. Thank you for that. Barry, let me ask you, what kind of population in Cleveland National Forest? Do you track that?
MARTIN: Well, I – Really, it’s kind of conjecture as far as the population, as Dr. Vickers mentioned. Lions have huge territories. Occasionally, what we’ll do as Tracking Team members, we’ll monitor areas and document that we’ve seen tracks or other signs and perhaps kill sites or scat, you know, that kind of thing, and we’ll document that. Very rare that we ever actually see a lion and we can kind of catch a feel for where a lion goes, what its routes might consist of and then we go out and get evidence of that. To actually come up with an exact number is pretty hard to do.
CAVANAUGH: So that’s interesting, Barry. So you – even your tracking teams, when you go out, you rarely see – you rarely encounter a mountain lion.
MARTIN: That’s true. It’s kind of – It’s humorous sometimes. We’ll be talking to people that don’t really go out hiking very often and then they’ll come back after maybe one hike and say, hey, you know, I just saw a mountain lion. And you question them and, you know, you ask them, you know, what it was that they actually saw, quiz them a little bit, and it sounds pretty reliable. So it’s a little bit frustrating sometimes for those of us who spend a lot of time out that we don’t actually see a lion unless it’s part of a capture event. So…
CAVANAUGH: It’s frustrating for you.
MARTIN: Yeah, it is kind of. But, you know, really, it’s – it kind of illustrates the point that Dr. Vickers made earlier, is the fact that lions really aren’t that interested in humans.
MARTIN: It’s kind of unusual that you’ll have these human and lion interactions.
CAVANAUGH: What about, Dr. Vickers, the second part of his question about fire and construction. What kind of impact do they have on a mountain lion population, and I’m going to ask you specifically mountain lions because that’s your specialty.
DR. VICKERS: Fire can immediately threaten them like any other wildlife at the time of the fire, and we have had a couple of our radio card lions die as the result of the Cedar Fire, for one, and Santiago Fire in Orange County. However, generally speaking, they will use the landscape after the fire fairly quickly in a similar way to how they did before, only sticking to what hasn’t burned for the most part. And they will follow the deer back into an area fairly quickly and, broadly speaking, over the course of time—and we have done research on this with the different fires—and as the landscape recovered, and they recover back into those areas as the deer do and resume use of those areas, you know, pretty quickly. As to construction impacts, that – certainly the mode of construction, the patterns of construction make – have a big role to play where they – where construction or development extends out into the wild lands, especially in finger-like patterns going up canyons or ridges where it, in effect, creates a peninsula of development that the lion then has to go around that perhaps they didn’t before. So it can lengthen their paths of travel and require more energy on their part and affect their overall ability to move through the landscape. It creates barriers as do roads and the border fence, and we are creating barriers all the time for these animals as far as their movement.
CAVANAUGH: We have to take a short break. When we return, we’ll continue to talk about San Diego wildlife in most – in particular, San Diego’s mountain lion population, and taking your calls about the kind of wildlife that you’ve seen in your neighborhood. 1-888-895-5727 is the number to call. And we shall return in just a few minutes here on KPBS.
CAVANAUGH: Welcome back. I’m Maureen Cavanaugh. You’re listening to These Days on KPBS, and we’re talking about the variety of wildlife and wildlife research that’s going on in San Diego. My guests are Dr. Winston Vickers. He’s associate veterinarian with the UC Davis Wildlife Health Center. And Barry Martin, founder of the San Diego Tracking Team. We’re taking your calls about what kind of wildlife you have encountered in your neighborhood, on a trail. 1-888-895-5727 is the number to call. Let’s take a call now. Geri is calling us from Julian. Good morning, Geri, and welcome to These Days.
GERI (Caller, Julian): Hello. Thank you for taking my call. And I live in, oh, a wooded canyon about a mile west of Julian on a tributary to Coleman Creek. And I did see a mountain lion outside my house early one morning a number of years ago. And I have seen a bobcat with a young one from my window, out across the canyon.
CAVANAUGH: What did you do when you saw the mountain lion?
GERI: It was five o’clock in the morning and I looked out and I saw this large tawny animal about the size of a Great Dane with a long, ropy tail. And I was pretty sure it was a mountain lion and it was probably looking for kittens that were safety under the house.
CAVANAUGH: I see.
GERI: And then I did want to get a better look at it so I carefully cracked my front door open and peered out and he had walked away from the house and it heard the noise and turned around and looked at me and we looked at each other for about 30 seconds and then it walked on off up the hill and back into the woods. So…
CAVANAUGH: Geri, thank you for sharing that personal encounter with the mountain lion. I appreciate it. Barry, I’m wondering, since – with the San Diego Tracking Team, have the number of sightings changed dramatically or substantially for any species over the past few years?
MARTIN: Well, sightings, I always hear about sightings. I hear about sightings a lot and people call me quite frequently to check out these instances. I’ll go out and look for tracks and sign to see if I can verify that it was a mountain lion and, I have to tell you, in most cases all I find are either big dog tracks or recently I found, in a situation, I found bobcat prints all over the place.
MARTIN: Yeah. So track’s another sign. So it was actually a bobcat that they had seen, and bobcats can get pretty big and they will be a little bit more edge-friendly. In other words, edges of developments, that type of thing, are more conducive to the presence of bobcats than mountain lions, I would say.
CAVANAUGH: Now, Barry, I know, for instance, I think that we, in larger urban San Diego, used to see more deer than we do now.
MARTIN: Right, we’ve had a decline in the deer population and many of our transects that we follow, our survey routes that we follow, have indicated that. And there are a couple of cases in point that I can tell you about. One is up in the Sabre Springs area.
MARTIN: And we started monitoring that way back in the early nineties. And, of course, since then there’s been a substantial amount of development along that corridor. And, initially, what we saw was an increase in deer sign along the route as the deer were compressed into a smaller area. Now, we don’t – Over time what’s happened is that the overall population of the deer has declined. There are still deer in the area but the number of scavenger species that are associated with development areas such as, oh, there are more raccoons, there are more possums, you know, that type of thing, tend to be more present – or, prevalent, in those areas now. So over time, with the advent of increased development, you do see shifts in the prey and predator base and the whole makeup of a – of these areas.
CAVANAUGH: Let’s take another call. Renee is calling us from El Cajon. Good morning, Renee, and welcome to These Days.
RENEE (Caller, El Cajon): Hi. Good morning. I’m a wildlife biologist. In fact, I just got back from tracking Flat-tailed Horned Lizards in the desert. But I was calling about mountain lions. You know, I get asked a lot, you know, what do you do if you see a mountain lion? And primarily as long as you have a healthy respect for them, I say enjoy it because I think it’s – you know, even though I’m out there a whole lot, I’ve seen them maybe three times over many years as somebody who’s out there almost every day looking for them. And I think a lot of people have this sort of unnatural fear. I mean, it’s – you should have a respect for them but the fact that actual lion attacks are incredibly rare and the fact that we have – Most of mountain lions I know, there are a couple of studies that showed a lot of them in our region actually die from being hit by cars. And I just wanted to kind of emphasize that. I’m an environmental consultant and we talk a lot about planning and development and how to do it to least impact wildlife, and I just want to emphasize how important these wildlife corridors are, places that Mr. Martin and others go tracking, and they’re just crucial for these mountain lions.
CAVANAUGH: Thank you for the call, Renee. Well, Dr. Vickers, it’s my understanding that we still have a pretty good population of mountain lion in California. Is that right?
DR. VICKERS: California Fish & Game feels, it’s my understanding, that the population is fairly stable and the biggest concern is that over time, as California’s population grows and more development occurs, is that populations of lions can be cut off from each other with barriers such as interstates and so forth. We see that in certain isolated pockets now where such as the Santa Ana Mountain Range in Orange County and extending down into San Diego County, and the Santa Monicas near LA where mountain lion populations are relatively small and have some difficulty apparently, or reluctance, to cross the interstates to reach other populations. And…
CAVANAUGH: So why is a limited migration, why is that a problem?
DR. VICKERS: Genetically, it can become a problem over long periods, generations, and also if you have an isolated population, they become more susceptible to things like catastrophic fire or a disease epidemic where in a large proportion of the population could be negatively affected if it’s down in the range of – In fact, going back to your question about estimates of numbers, the only good published estimate that’s occurred in the region based on research was that Paul Beier estimated 15 to 20 adult mountain lions in the Santa Ana Range, for instance, and that’s not a big number if you had a fire the size of the Cedar Fire, which would basically take pretty much that entire mountain range. So they are – they become more susceptible to major impacts like that.
CAVANAUGH: Let’s take another call. Stephen is calling us from La Jolla. Good morning, Stephen, and welcome to These Days.
STEPHEN (Caller, La Jolla): Oh, thank you. And I’d also like to thank your guests there on the Tracking Team. They really do an incredible job providing us information that’s a part of what’s going on in San Diego. I was on the Environment Working Group at the San Diego Foundation that’s funded them from time to time, so they do a great, incredible job. My question had to do with there was a really interesting article, I thought, in the Union-Tribune recently talking about the range of lions but then the thing that was distressing was is that, I recall, the lion was ultimately shot by, you know, a farmer who thought that this lion might be threatening their lambs or something. And I was just wondering, I mean, you know, I mean, is it just open season on mountain lions if you’re afraid of them or if they’re going to get your cat or dog? Or, I mean, is there some responsibility of people to just kind of just accept that type of interaction because they’re moving into their territory?
CAVANAUGH: Thank you for the call, Stephen. I’d like to get your response, Dr. Vickers, about that. When can a rancher or a person shoot a mountain lion? And is there any consequence to that?
DR. VICKERS: Yeah, the state law put into place by Proposition 117, which outlawed sport hunting of mountain lions in California, gives a – any animal owner who loses a mountain lion – an animal to a mountain lion, and that is confirmed by Fish & Game, the option of requesting a permit to kill the lion or have the lion killed, and that is what happened in the case that he refers to that was in the Union-Tribune and that was one of our study lions, a radio collared lion, a young male who was – had migrated actually from Orange County and had gotten to the border and turned around, which actually most of our lions have except for one that has managed to cross the border, speaking of barriers.
DR. VICKERS: But that lion was legally taken because it is strictly up to the landowner. Fish & Game does not technically have the option of denying that permit if they can confirm that an animal has been lost. It doesn’t remove the broad responsibility we all have of protecting our pets and livestock but it is a legal option when people lose an animal. And we have surveyed – actually surveyed residents of San Diego County that live in the rural areas and have livestock and pets and in our surveys approximately half of the population did adequately protect their animals with – at night, which is primarily when they’re at risk, by housing them in secure housing pens with tops, and barns and sheds that a mountain lion cannot enter. But that is the only way to be sure that your animals are protected from mountain lion predation if you live in the areas that mountain lions roam.
CAVANAUGH: Barry, do we have any statistics, any numbers, about how the border fence is impacting the migration of wildlife from San Diego into Mexico?
MARTIN: I do recall that the Conservation Biology Institute did a little bit of work in that regard. I don’t have those numbers at my fingertips…
MARTIN: …but I can tell you anecdotally that it is having quite an impact. I think – I do have to mention, though, that the biggest impact is with those people coming up. And no matter what your thoughts are on the international travelers, such as we might call them here, it is kind of a humanitarian disaster in effect. There are a lot of people being forced into really inhospitable areas of the desert and they’re dying out there so I think that’s a pretty bad problem. The wildlife is another story where, in the case of M-56, that Dr. Vickers just was talking about, that lion went down close to the border and then I don’t know if he tried to get across or if his instincts were leading him south and if he would’ve gone further south, if he would’ve been able to cross, I don’t think that encounter with the livestock would’ve occurred. So, you know, it’s one of those chain of events type of things…
MARTIN: …that we see frequently.
CAVANAUGH: Let’s take another call. Sandy is calling us from Allied Gardens. Good morning, Sandy, and welcome to These Days. Sandy, are you with us? Mark, from Carmel Mountain Ranch. Good morning, Mark. Welcome to These Days.
MARK (Caller, Carmel Mountain Ranch): Good morning. I’m wondering about the coyote population. I’m a private pilot and in between the two runways of Gillespie Field the other day I saw a lone coyote.
CAVANAUGH: Saw a coyote, okay. What about the coyote population, Barry?
MARTIN: Oh, they’re thriving. They always have. They are the most resilient species, I think, in the United States. Due to the history, we can look back. They’ve been the most hunted over time but yet they continue to thrive. In the case of, you know, coyotes running across runways, actually I was just flying up to French Valley this morning from Gillespie Field and listening to the radio at Ramona, a pilot reported a couple of coyotes crossing the runway there, so…
CAVANAUGH: Oh, wow.
MARTIN: …be careful. So I don’t know, there’s – there’ve been eradication programs on airports and various other places but what happens is it kind of throws things out of kilter with – You know, you’ll just have another family or couple of coyotes will just come in and take over the territory…
MARTIN: …basically is how it works.
CAVANAUGH: Dr. Vickers, in the minute that we have left, could you tell us what would be maybe the one most important thing that people can do if they want to help protect and preserve wildlife in this time of urbanization and so forth. What can we do?
DR. VICKERS: In so much as individuals can politically support conservation efforts, in as much as they can support them financially, there are many groups and land trusts and any number of them. I won’t start naming them, but any number of them out there, Nature Conservancy and others that need the support. The county needs the support in its efforts, which are substantial, to preserve lands and to preserve these corridors. And that’s probably one of the main things in recognizing that these animals are at much more substantial risk when they live around us and that we have to find a way to co-exist. I hadn’t mentioned earlier but approximately half of our 53 mountain lions that we have entered in the study have died, mostly of human-related causes, so…
CAVANAUGH: Dr. Vickers, we are out of time but I thank you so much. Thank you and Barry Martin for talking with us today about this, and for the people we couldn’t get on the air, please do post your comments, KPBS.org/thesedays. You’ve been listening to These Days on KPBS.