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

Alan Franklin
Research Scientist
Colorado Cooperative Fish & Wildlife Research Unit
Colorado State University
Fort Collins, CO

Interview with Alan Franklin:

My primary research is on the Northern spotted owls in northwestern California. And I’ve been conducting, along with Rocky Gutierrez and some other folks, a population study in northwestern California since 1985 – this was our 20th field season this year on that project. Basically, what we do is track mark individuals over time, and locate their survival, reproductive success, and try to relate that to external factors such as weather, habitat, and so forth. As part of that study, we’ve also been looking at the dynamics of small mammal, which is what the owls primarily prey on, and then we also recently this year started a project looking at the effects of West Nile Virus on our population of Northern spotted owls as well as two populations – one on Tupa tribal lands, and one on Simpson Timber Company lands. And we’ve also been collaborating with Mark Seamans and Michelle Crosier and Rocky Gutierrez on their population study of California Spotted Owls in the El Dorado. In addition to my primary research program on Northern spotted owls, I’ve been involved with Mexican spotted owls. I was on the Mexican spotted owl recovery team for a while, and I’ve also been involved with some of the management issues and research issues with the California spotted owl.

WNV, not sure exactly what’s going to happen, high probability of causing mortality, as virus has swept across, high mortality on owls, primary evidence comes from a raptor rehab high mortality in Ontario.

It’s a big concern for us, because it’s sort of a wildcard. We know it’s going to affect them to a certain degree, but we don’t know how it’s going to affect them, if it’s going to be a big effect, if we’re going to see a big population decline, or whether we might see a population decline and then it sort of tapers off. Hopefully we’ll be able to keep that going for at least five to ten years as we study this population to see what the effects are.

One thing that we’ve found is that wet rainy Springs can have a negative effect on survival and reproduction, high populations of mosquitoes, Keelis Parcelis Mosquito seems m get high pops, high prevalence of the virus, closely tied to the weather. During certain weather conditions, population explosions. Double whammy, really hard winters, wet cold, winters and Springs could affect their survival and reproduction, and also increase the incidences of the virus that could have a negative effect.

In the last decades, had more El Nino events in last decade than in previous ten years of the study. One of the predictions of global climate change is the frequency of El Ninos is going to increase. But whether that’s natural variation, or whether that’s due to global warming, I have no idea. That’s one of the things that we’ve currently looking at this Fall, is the effects of these El Nino events on spotted owl populations, but also look more closely at the existing record that we have – we have good weather records for this area for the last 50 years, just to see if this is sort of an abnormal situation, or whether this is the way things vary over time. It’s really important to get the whole background perspective before you start jumping to conclusions that this is sort of unusual.

We’ve only been looking at them for 20 years, I terms of the forests around here, 20 years is a really short time, older forests is a really short time, those kinds of forest start at 120 years old, one problem that you do have, have drought, first six years of study in a severe drought, owls do reasonably well, risk though is catastrophic wildfire, work primarily on National Forest Lands, been suppressing fires late 1940s, 1950s, been a lot of ingrowths, denser than in a natural fire regime. This area used to have a frequent fire return interval, fire was part of the natural disturbance regimen, suppressed for a long time, given a good long term drought, right conditions, catastrophic wildfire here could cause a lot of damage.

We work in what’s called the Climate physiographic Province, range of the Northern Spotted owl occurs over a number of different, what they call ecological vegetation provinces. And, we’re in the Southern in, where we have older forests, which consist of both conifer species such as Douglas fir, and hardwood species such as tan oak and madrone. It’s a fairly unique area. For example, in our study area it used to burn fairly frequently, historically, whereas if you` go 40 miles to the coast, then you have spotted owls in old-growth redwoods, for example. Those areas have a much less frequent disturbance from natural fires.

ES:

AF: Right, and the same concerns apply for the California owl in the Sierra Nevada mountain range. They also have a historically frequent what they call a fire return interval, that is that fires occurred – in our area for example – every 10 to 20 years in a given stand of trees.

ES:

AF: Well, it’s pretty much the same thing that we’ve been doing for the last 20 years – is that we cover a fairly extensive area. We have a primary study area, that we call the Willow Creek Study area; it’s about 112 square miles. And we surveyed that entire area for Spotted owls every year. And we also have some satellite areas that extend almost up to the Oregon border, to about halfway down to San Francisco, and then across over towards the central valley of California. And, what we do, is that I have six other people that work with me on the population biology portion of the project, and then we go out every day and survey for Spotted owls, and when we find them, we see if they’re previously banded, and if they’re not, we capture and band them. We check to see if they’re reproducing, and if they produce any young, we capture and band those as well. That’s pretty much what we do every year. It’s a fairly straightforward design, although doing it is not quite so straightforward because we work in some pretty rough country. But that’s basically what we do year after year.

Hazards run the gamut from illegal pot growing, steep terrain, Mountain lions, mountain lions more of a hazard, have gotten more inquisitive, mountain lion attacks on the coast, the go up and down every year, illegal pot growing, WNV, limes disease,

Populations been fairly stable, catastrophic weather events, hard, rainy winters, see decrease in survival of birds, depending on how long, complete breeding failure, very few young produced, El Nino, slow buildup of population from previous years, catastrophic events, pop builds up, high quality habitats, mix of older forests and suffer much less

Hard question to answer, declining at rate that’s pretty low, declining very very slowly, in a grey area. Based on what we’ve seen, fairly

Found that a t4erritory that has interior older fore3est, some distance away form an edge, from a clear cut, some blocks that what it does is that it balances edge, support wood rats and deer mice, balancing act maintaining older forest and edge, in minds eye, blocks of older forest we found that areas, lower reproduction, high quality habitat is blend of older forest critical point there is that, interior older forest is still a critical long, sliver, no interior more like contiguous blocks, older forest

Hard to say over the entire range, have some good areas in National Forests that we’ve logged in the past might think that some of the best is in National Parks, is patchy, have areas where owls occur, just having old growth forest, a lot of differences have a really strong hard outlined hypothesis, one hypothesis is that it provides stable thermal gets extremely hot, July Aug – temps in 90s, even 100s older forest is much cooler, if you walk from clear cut, much cooler protection from predators, strictly nocturnal, ears are not in line, relates to their ability to solely hunt by hearing Spotted owl can hunt in great horned owls availability of nest sites, very old broken top live trees chimney, side branches grown up, shade over the chimney, very rare types of trees relative to doesn’t explain, still really don’t know why, depends, territorial birds, tend to occupy same territory for life, in our particular area, occupy larger home ranges in winter, the breeding overlap 1-2 square KM, dependant on their territories whether they eat wood rats or flying squirrels, WA have several in our area, it depends on a number of different factors. I mean, they’re territorial birds, and just in real gross, general terms, they tend to occupy their same territory for life. And, in our particular area they occupy them year round. So, the size varies seasonally. It’s roughly 1-2 square kilometers.

Well, I think that West Nile Virus is definitely a new type of threat. It’s an introduced disease, and it was introduced into the United States in 1999. And it’s appeared in New York City, and has since spread across the country. As I said before, we really don’t know what the impact of that is. We expect, initially, that there’s going to be mortality from the disease. But whether that continues on, or the extant of it, or whether they’re going to face imminent extinction because of West Nile Virus – we have really no idea.

Another threat is barred owls. They’ve essentially invaded the range of the Northern spotted owl. They’re larger – they tend to be more aggressive, and there’s some evidence that they do displace spotted owls. But again, we know that they have an effect, but we don’t know the extant of the effect, and whether it’s going to uniformly occur across the range of the spotted owl. to give you an example, it seems to be much more of a problem in the state of Washington than it is in our area. In our study areas we still have very, very low numbers of berred owls over the last 20 years. But there’s still that unknowable future where they could increase dramatically over three or four years, as they have done in some areas. It’s kind of interesting, for example, that in Redwood National Park they do have high populations of barred owls relative to our area, and also relative, for example, to the Simpson Timber Company lands which are nearby. Again, we know we can identify it as a potential threat, but we don’t know how much of a threat it’s going to be.

And then, another threat is this problem with catastrophic wildfire, where you’ve had fire suppression for a long period of time, and you’ve had a lot of vegetation growth during that time, and essentially you’ve had a lot of fuels build up in these forests. But again, we don’t know to what extant that threat is really going to play out. So, we can identify threats, we can identify them and say that yeah, this is going to be a really big threat, this can be a big problem, but we don’t know when it’s going to hit, how it’s going to hit, and to what extant it’s going to hit. So, we’re sort of just waiting to see what happens. There are certain things that can be done, for example, with catastrophic wildfires there’s certain management strategies that can be done like for example thinning of forests. But, one of my concerns about that is just going out and thinning forests in response to wildfire in Spotted owl habitat, unless you really know what you’re doing, unless you maintain the integrity of the structure of the forest, the thinning could be just as bad as the catastrophic wildfires. So I think that there’s a lot that we still need to work on, there’s a lot more that we still need to understand in order to deal with these threats.

Wildfire, not always the case, by catastrophic to owls, does burns forest down to the ground. Have had wildfires in our study areas, in some areas, intense, some not as intense, some owls survive and persist having a fire is not necessarily bad, burning huge areas, stand replacing fire that takes out everything. Part have not been, burned up some owl areas, effects are equivocal in how they affect, severity,

Being in the wrong place and the wrong time, a lot of lightning strikes, can really have a big catastrophic event. Ecologist Tom Jimerson reconstructed fire history maps, 1865 huge catastrophic fires, area had been fairly settled historical accounts, flames o sky, large areas impacted, historically, could see that again. Fire suppression and ingrowths added fuel to that scenario. Get a year with a lot of growth followed by. A lot of it is speculation; don’t know what’s going to happen.

The way we’re approaching it is, first we collaborated with people who are experts in West Nile Virus. And those are folks at the National Wildlife Research Center in Fort Collins, who have worked with the virus all over the country. And, we’re kind of in a unique situation in that we’ve been tracking this population for 20 years, where the virus has been essentially absent. And it just arrived this year in our area, in fact in August it’s been detected in Humboldt, Trinity, and Mendocino counties, which encompasses a good portion of our study area. And, basically the only way you could study it is in sort of a natural experiment. We have 20 years of data before the virus arrived, and now the virus has arrived, and we’re going to look at the population with the virus in the area. And the way we’re looking at it is we’re trying to determine where we have a sampling scheme looking at whether the mosquito vectors are even in the area, and that is there are no mosquito species that are known to be what are called competent vectors – they just do a really good job of passing the virus to birds. And, birds are the primary hosts for the virus. So, are the vectors even in the area? Second, is the disease actually in the area? I mean, you could have it say, on the coast, but not necessarily inland, or it could be in this type of habitat but not in another habitat. So we’re sampling small mammals to look for the prevalence of the virus, and small mammals tend to pick up the virus and don’t die. One of the problems you have is that if it’s really lethal, you’re never going to see – for example – we rarely find dead owls in the woods. And so you might see a drop in survival, but you can’t really say, well, it’s due to the virus. But if we do pick it up in owl territory, and there’s a really high prevalence of the virus, then we can track our survival rate along with those prevalence rates. And so that’s how we’re looking at the second question, of whether the virus is even in Spotted owl territory. And then finally, we’re looking at – well, is it even in the owl? We’re drawing blood from all the owls that we capture, looking for antibodies that would tell us whether they had it or have it. But we’re actually taking oral swabs to see if the owls actually have the virus in their systems. In other words, they could get the virus, and recover from the disease, but they’ll still have the antibodies, and that’s what you get from the blood samples. But the oral swab actually tells you if the owls have the virus, whether they’re sick. And so, we hope with that three-pronged approach, over a number of years, that we’ll be able to sort out whether other factors such as weather, or habitat quality are affecting survival rates versus the virus. It’s sort of a really slow type of science. And then, in addition to that, we’ll probably end up doing some key experiments, looking at how Spotted owls, or owls in general, how well they survive once infected with the virus. Some of that work has already been done, for example, at the Center for Disease Control.

ES:

AF: Well, we take a swab, and when we have a captured bird in hand, we open its bill and swab the roof of its mouth and the back of its throat, the same way it happens to you when you go into the doctor with a sore throat. It doesn’t hurt the owls or anything, it’s probably a little uncomfortable, but it doesn’t hurt them, the same way that a doctor takes a throat culture from you.

ES:

AF: We don’t know, generally it’s been fairly lethal with owls, but again, we’re talking with fairly low sample sizes and, again, it’s like people. When, for example, when smallpox was introduced into North America, it had lethal effects on lot of Native Americans, but some of them survived it. And we’re hoping the same thing will happen with the owls. Some have a natural immune response to this virus. And so what happens, if that’s the case, then when the disease first passes through the area, might cause a high mortality, but then that mortality is going to decrease in the future, if you have individuals who are naturally sort of immune to it – get the disease but aren’t affected as severely as other individuals. There’s always that sort of variation in a population. So whether that variation exists, depends on how the population is going to react to the disease.

ES:

AF: Well, yeah, that possibility exists, it has happened with some crow populations. What’s difficult is…we’re sort of in a unique situation with Spotted owls because, we have population studies that have been going on for a long period of time. So we have a really good idea of what the background survival rates are. And then, if you introduce this negative influence, you can see how well they react. That hasn’t been the case with other population studies on birds in the United States, or at least it hasn’t been published in the literature. So, crows suffered a high mortality in certain parts of the country, but we really don’t understand what the long-term effect on crown populations has been. One problem that we have is that the virus has only been in the United States for five years now. That’s not a very long time, when you’re studying population dynamics in wildlife species, five years is a short-term study. It’s still sort of an open book. We really don’t know what the long-term effects are going to be. My watchword on this stuff is expect the unexpected. I have an idea of what might happen, but I’ve been wrong in the past, and I could be wrong in the future. And that’s sort of where you maintain your objectivity and collect data, and over a long period of time see what exactly happened.

When I was 5 years old, got bitten by box turtle, since in grade school, spotted owls, working on them in 1980s, population biology, tend to be very long lived, not a lot of long-term studies, a lot of fun to work with, In terms of a population biologists more questions come up during in study than you answer, management viewpoint, interested in conservation issues, also one of the reasons, gets frustrating

Looking at the effects of habitat and rates of survival of older forest was really the prime component, the more you had, the better the survival it really surprised me that these edges played such an important role. Was not expecting that, fire influencing and that’s one that we’re early sterile stage edges are where wood rats are abundant and available aren’t forage in early, too dense, bird may be safe from predation, meets, some are bleeding across the boundaries, can’t get funding for also found some surprising things, rough data might actually attract flying squirrels, owls eat them, flying squirrels and wood rats more forest heterogeneity, not like shattering plate, older forest and fragmentation, more heterogeneity, balanced with edge pulled off to deal with conservation issues.