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TOM WHEELER:

Welcome to the Econews Report. I'm your host this week, Tom Wheeler, Executive Director of EPIC. And we are talking about barred owls on this week's show. And joining me is Vitek Jirinec, Research Scientist at the Integral Ecology Research Center based out of Blue Lake. Hey, Vitek.

So you recently published a paper, let me pull up the title, Invasive Barred Owls Select Old Forest Structure, Functional Habitat Loss for Spotted Owls and a Threat to Old Forest Fauna. So we are going to be talking about barred owls, your paper, and the way that barred owls can impact one of my favorite critters, the northern spotted owl. So let's just begin with some barred owl basics. And I know that you researched barred owls previously in another life of yours, way down in Louisiana, where barred owls are native. And there barred owls were popping up maybe in a place that folks might find to be unexpected. Tell me about your research down in Louisiana on barred owls.

VITEK JIRINEC:

That's right, Tom. So I spent about four or five years studying barred owls in the capital of Louisiana, in Baton Rouge. And I was essentially finished with my graduate work, spending a lot of time in front of the computer, and I was looking for ways to get outside again. And I got together with my faculty colleagues, and we decided to track barred owls within the confines of Baton Rouge. And what we found is that they are really amazing generalist species. They can really make do with almost anywhere as long as there are some trees. And in fact, we found that about a whole third of the footprint of the capital of Louisiana qualifies as barred owl habitat. But they don't choose any for us. If they have the choice, they would pack those older, the places with the older trees.

And we've actually done this neat analysis, I think, where we asked the question, does barred owl selection track human affluence using the census data? And we found that, yes, it does. And it's not because these barred owls are some kind of Scrooge McDuck, you know, they like money. They track places with lots of greenery, old trees, and those wealthy neighborhoods is what has those features in it, these large oaks. And so they like old forest, even in their native range. And once they got here to the west, they found the oldest trees on the continent.

WHEELER:

And so I think that this is a fun story because it helps to illustrate a couple of different things about barred owls. As you said, they are habitat generalists. They can exist in a wide variety of habitats, but they are also preferential and they will try to seek out older forests, even in their native range. And also that their native range is not here on the West Coast, that barred owls are native to Eastern North America and are only recent immigrants to the West Coast of the United States and West Coast of North America.

So this barred owl invasion, as it's often called, is theorized to have pretty significant impacts on northern spotted owls. Barred owls are generalists. They are a cousin to the northern spotted owl. To the untrained eye, they often look pretty similar to a northern spotted owl, but they are also considerably different too. What do we know about the diet of barred owls here on the West Coast relative to northern spotted owls?

JIRINEC:

As you mentioned, they're generalists, so that is a concern with their habitat as well as their prey. Our collaborators at the Reserve of Wisconsin, I think, found something like 78 different unique prey types in the stomachs of barred owls here in the West. And from my work in Baton Rouge, I've seen barred owls eating crawfish, eating snakes. I've got a great photo from one of my friends that pictured one eating a crawfish, but it didn't just scarf it down really quick. It first de-clawed it very expertly before eating it. So that just speaks to how good they are at eating essentially anything that's small enough for them to subdue. Whereas the spotted owl is a prey specialist. It essentially eats three prey species, and that's mostly it.

WHEELER:

And those three are wood rats, flying squirrels, and tree voles.

JIRINEC:

That's right, that's right, exactly. And so, as a result, they have to have bigger home ranges to find more food, so they occur at much lower densities than the barred owl, and they don't impact a lot of these other critters, like salamanders, like insects, that have not evolved with the pressure of the barred owl over millennia.

WHEELER:

Yeah, so Northern Spot Owls, as you said, evolved in West Coast forests and West Coast ecosystems are, are evolved with them. Whereas the, the spotted owl is not native to the West Coast and it's common. It has more diverse prey base and so could be putting new and, and extreme pressures on, on prey species that haven't been felt heretofore. So the Northern spotted owl has gotten a lot of the attention from spotted owl invasion, because I think it is probably the most well-studied bird in North America. We have a lot of data about Northern Spotted Owls and they're really easy to study in some respects because they have these fixed home ranges so that you can go back and see the same birds year after year. And so we know a lot about them and because we know a lot about them, we've been able to discern this causal relationship, which is effectively more barred owls equal fewer spotted owls.

But there are all of these impacts from spotted owl invasion that we might not be seeing because the data isn't there or the data is unclear or complicated from all these other factors. I think that that, that is an incredibly important part of this story that we're, we talk about spotted owl invasion, not just as barred owls versus spotted owls. We have to make a choice on which owl we like more or something like that, but it's barred owls versus West Coast forested ecosystems. And so we talked about spotted owl invasion and that they're not native. How, what do we know about barred owls coming to the West Coast? Did humans perhaps have any sort of role in, in encouraging or facilitating this home range expansion?

JIRINEC:

That's right. So what we understand is that historically, the Great Plains acted as a really good ecological barrier for a forest owl, like the barred owl, right? It was a treeless expanse. And a barred owl, again, is a forest associated species. It just couldn't hop across. But especially with the arrival of European settlers, those Great Plains have started to change. People like to plant trees in their backyard. There was fire suppression, extirpation of these large herds of bison that have all kind of kept the trees out. So all these factors have resulted in more trees in the Great Plains, and that created essentially a bridge for this forest owl to hop across. And then it hit this great expanse of forest here on the West Coast.

WHEELER:

And so we have our first recorded sighting of a barred owl in British Columbia, and they've been moving down the West Coast. So British Columbia has had barred owls for the longest. Perhaps unsurprisingly, spotted owls are doing the worst in British Columbia, where the species is functionally extinct. There's maybe an owl or two left in the wild, but it's gotten so bad that we have captive breeding programs in British Columbia to try to recover the species there.

Then down to Washington, going down the West Coast, going down the Cascade Forest. In Washington, the northern spotted owl is nearly extinct. Down into Oregon, where it's doing better than in Washington or British Columbia, but everything's trending towards extinction. And now here to northern California, where only in the past couple of decades have barred owl numbers been large enough to start to see a noticeable effect on northern spotted owls.

And now we are starting to see the same thing that has happened in our fellow West Coast states, which is the steepening decline of the northern spotted owl, such that probably within our working lives, we could see the species go extinct in the wild. Extinct, meaning functionally extinct, not present on the landscape in any meaningful numbers and not completing the role that the species would have in the ecosystem. There might be one or two owls holding on in areas that were not for some reason subject to pressure by barred owls. But it is a sad story and one that might be preventable. So your organization, the Integral Ecology Research Center, give us a background of your work there and then we can kind of get into how you started to study barred owls.

JIRINEC:

Yeah, so I'm a habitat ecologist personally, and I'm focused on birds. And so a lot of my work at IRC has been within the realm of studying habitat and what it means for for species like the barred owl, like the spotted owl. And we're a conservation and research organization that was around for the last 20 years or so. And we've done a lot of work on the effects of rodenticide exposure on local sensitive species. And it's actually where the barred owl story touches on, too, because we got this funding to do this work through the Cannabis Restoration Grant Program, trying to study potential effects of cannabis cultivation here in the remote forests on on wildlife, and that includes pesticide exposure. And so we knew that the barred owl removals were happening, and we wanted to essentially harness that removal program, the removal research, to learn something about pesticide exposure here in our remote forests.

WHEELER:

And what an interesting and abundant source of data, right? That probably was not terribly easy to access previously. You now have birds that you can necropsy and study their livers.

JIRINEC:

Right, you know, there's a lot of what you can learn from these owls when you have them in hand and unfortunately something like, best, is that exposure you might need to get the liver, and the only way to do that is from a deceased specimen. And so again, these rules are happening. We might as well capitalize on on the fact that they are, and I want to point out that there is a lot of good science happening on top of these removals. Just imagine the data that you can get from from single one single owl. At IIRC we've collected something like 45 different samples for from each of these owls, and that includes tissue samples, feather samples ... we have GPS data accelerometer data from some of them .. just you name it, a lot of different samples.

And so those will tell us a lot about what's what's going on between spotted owls, barred owls, the effects of barred owls on the local ecosystem, pesticide status for for not only other species like the spotted owl, but also for human health. Again, we can do a lot from these. So, yeah. And here is this paper was one example of what what you can get from these removals.

WHEELER:

Yeah, well, I will just dwell on this a little bit more. So the research that you're doing on barred owls that have been killed for other research purposes, it's really interesting because it provides a window into something that we would otherwise not be able to see, which is the role of toxicants in our forests. Toxicants are often associated with trespass cannabis grows on federal public lands. So while barred owls are a diverse eater, they do include rodents, and rodenticide use from trespass marijuana grows is something that's going to not only impact barred owls, but also impact other species that are gonna be harder for us to study, things like the Northern spotted owl, things like the Pacific Fisher, Humboldt Martin, other critically imperiled wildlife that also call these forests home. So from studying barred owls, we're getting a picture into broader ecosystem health and the role that, among other things, toxicants will play in these ecosystems.

Okay, so you have a new paper out. I think that it was released just in the last couple of weeks or so. So, congratulations. Again, the title of that is Invasive Barred Owls Select Old Forest Structure, Functional Habitat Loss for spotted owls and a Threat to Old Forest Fauna. And you can find a copy of this publication, if you're so interested, on the Integral Ecology Research Center's website at IERCEcology.org. So tell me about the subject of your research and then we'll get into findings in a little bit.

JIRINEC:

Right, so I mentioned that the reason for us, the original reason for this project was to look at the connection between cannabis and barred owls and the local ecosystem. So one of the questions that we pitched is to see, well, why don't we track these barred owls before they get removed and see whether owls that have cannabis infrastructure within their home range, if they are more likely to be exposed to some pesticides.

But like I mentioned, we're trying to maximize the good that's being done with these removals. And so one thing that came about during the past couple of years is, well, why don't we just simply look at how much spotted owl habitat is within each of these barred owl home ranges since we only have the data. And so those were some original analyses and they show that there's actually quite a bit of what's the mapped spotted owl habitat in each of these barred owl home ranges. In fact, about 64% of each, on average, each barred owl home range is spotted owl habitat. And we try to publish those results and reviewers wanted us to do more work.

So we eventually went deeper into the analyses, did some habitat selection work, and in fact, we found out that they select for some of the best spotted owl habitat. And so I think that tells us at least part of the story why the barred owls were driving spotted owls down to extinction. They like the same things on the landscape.

WHEELER:

And when they have overlapping ranges, when there's a spotted owl and a barred owl, both are territorial owls. The spotted owl is slightly smaller than the barred owl, and the barred owl will then beat up the spotted owl. It potentially kills spotted owl into leaving that territory, abandoning its historic territory, and the barred owl takes over. The spotted owl then is no longer reproducing, and now you can understand why spotted owls are declining. With more barred owls, fewer spotted owl nesting home ranges, less reproduction, impacted adult survival, so on and so on. Sorry, continue.

JIRINEC:

Exactly, this is a classic illustration of the competitive exclusion principle in ecology, which is where you have these closely related species that overlap in resources. If one of them is a better competitor, it's going to win out eventually and drive the other species to extinction, and that's what's happening here. But the notion that the bottles like old forests is not new, that's not something that we've found out, but we put some, I think, good numbers on what it actually means in space, and we also went the extra step. If we remove these barn owls, we essentially free up a lot of this landscape that constitutes a spotted owl habitat, so we can essentially have a restoration of habitat by these removals of barred owls.

WHEELER:

And as I understand it, from talking to other forest ecologists, and I don't know if there's been a paper that has stated this well, so maybe this is a call to my friends in the academic world, there is a belief that when a barred owl pushes a spotted owl off of its nest site, that it won't necessarily die, but it will go into the forest and it will no longer vocalize, it will no longer be territorial, it will become what is called a floater, and that these floater owls will continue to exist, but they won't reproduce -- floater spotted owls, that is. And when a barred owl is removed, if there is still a floater around, the floaters can come back and reoccupy a previous nest site, or they could reoccupy spotted owl habitat that is now newly freed because of barred owl removal, and they can begin to reproduce again.

So there is a pretty quick positive feedback when you still have spotted owls present. So that means here in California, we might see positive beneficial effects faster from barred owl removal than say in Washington, where there are fewer spotted owls to come back and recolonize previous sites.

Okay, so important findings from your paper that barred owls preferentially select spotted owl habitat, that there is significant overlap between where barred owls are and where spotted owl habitat is, and that removal is useful to bring back spotted owl habitat. Let's talk about some of the management implications of your paper.

So of course, barred owl management is itself controversial. So the US Fish and Wildlife Service has published the spotted owl Management Strategy, which is a permitting program to allow for barred owl removal more expeditiously under the Migratory Bird Treaty Act, and has a plan by which barred owl removal is prioritized in areas that would have the best or greatest beneficial effect to northern spotted owls. We also have barred owl removal occurring outside of that barred owl management strategy by companies like Green Diamond Resources Company, by Sierra Pacific Industries, and we have tribal leaders, too, with the Hoopa Valley Tribe, and Mark Healy there, a friend of the show, as well as the Yurok Tribe, all of which are doing barred owl removal. How do you see your paper contributing to this larger public discussion about barred owl removal?

JIRINEC:

Well, one thing that we try to argue in the paper is that we really should consider barred owl presence in the discussion about how much habitat for spotted owls is actually out there. And I'll tell you a little bit of a story here. I was an undergraduate student here back in the late 2000s, taking classes from Matt Johnson here in the model department. And Matt is a big habitat ecology researcher. He wrote one of the most cited reviews about habitat and habitat quality in birds and how to measure it. And one thing that Matt tried to hammer in that paper is that habitat is not just vegetation, right? If you look at the original biological definition of habitat, it's the resources and conditions that lead to occupancy over certain species. Habitat is species-specific. And again, it's the biotic and abiotic conditions that lead to occupancy.

So for spotted owls, the consideration about how much habitat is still out there really mostly revolves around how much vegetation structure there is in the forest. But I think that's necessary, but it's not sufficient because as the science showed us from a number of papers now over lots of years of research, where bottles are, spotted owl occupancy drops, right? And so you could think about bottle as being that biotic feature that precludes spotted owl occupancy. And since the Northwest Forest Plan took place in the early 1900s -- not 1900s -- I wish it was that early, we've, I think we've done a pretty good job of saving that structure on federal lands.

But we've seen spotted owls dropping in the same area, something by like 75%. Even though this map, quote unquote, habitat has actually gone up a little bit. And so I think if we really thought about the bottle as a part of this calculus, we've really witnessed some of the most drastic declines of spotted owl habitat on federal lands in the last 30 years. And if by that lens, you really can restore habitat without doing something about the bottle at the same time, which is unfortunate, but here we are, this is conservation in the year 2026 right now, we're in the throes of the sixth mass extinction, and there are no easy choices, unfortunately.

WHEELER:

There aren't, so the question I get all the time, EPIC is in support of barred owl removal. We've gotten a lot of flack from our friends in the animal rights community for this position. One question I get is, is barred owl removal a forever problem? Are we going to have to institutionalize this and have guns in our forests forever killing barred owls?

JIRINEC:

Well, we unfortunately missed the boat to do this cheaply, right? We kind of waited too long and now there's a lot more bottles out there than there were maybe just 30 years ago. And our inaction led us to this being a more difficult challenge to solve than what it would have been a while ago. But this is not a eulogy, this is a solvable emergency. We've determined as a society that it's worth doing weed control, for instance, to maintain forest.

And you can think about Hawaii, New Zealand, Australia, these are places that are battling invasive predators themselves. They're doing it at a national scale. And that's a choice that we we can make or not make. But if we do removals or not, animals still die, unfortunately. These are generalist predators, they occur at more high densities than the native spotty owls, and they're not out in the forest eating grass, unfortunately, right? So that's unfortunate. If we remove them, these owls are not gonna consume the thousands of small critters, like salamanders, flying squirrels, tree wolves...

WHEELER:

And there's nothing native or natural about this. Not that there's... We're confronting ideas of wildness and natural states here. This is a non-native, some call it an invasive species. So it is not as if we could allow things to go back to some state of being that didn't include human modification. We're inextricably linked into this. And to your point that it would have been great to do this maybe 30 years ago, the problem would have been far easier to solve. That's true for the Northern spotted owl. We are at that moment for the California spotted owl.

Barred owl invasion in the Sierras and California spotted owl habitat in the range of the California spotted owl is relatively new. We're at that leading edge of the invasion event. And so there is an opportunity here with barred owl removal to make sure that we clean out the Sierras of all the barred owls and then create a bright line after which no barred owl will be present. And we are 30 years too late for the Northern spotted owl, which is a tragedy. And it's going to take millennia for us to hopefully build back up our spotted owl populations.

But we can prevent the same thing from happening to the California spotted owl. But the time to act is absolutely right now. And every year that we wait is going to be more and more barred owls on the landscape that are going to be more difficult to remove. And the impacts are gonna be greater for that species. Oh boy.

Okay, so what's next? What is your next research project now that you've done this one? What do you have on the horizon?

JIRINEC:

So like I mentioned, we have a lot of different tissues collected and we have several different questions that we're studying using these tissues and hopefully next couple of months we'll have some information about rodenticide contamination on the landscape and some of the sources of that contamination and this is just one of several different papers that we have on the horizon now. So I don't want to talk too much about it because they're still in the process of being published, but stay tuned for that.

WHEELER:

So, so, trespass cannabis grows continue to be an issue despite legalization, we still have an issue with both grows and and all the toxicants associated with them both past and present.

JIRINEC:

That's correct, and that's going to be part of the story that we'll tell, again, with these bottle removals. And we wouldn't be able to tell that story otherwise, at least very easily.

WHEELER:

Okay, so California, we are leading the way on barred owl removal, as we said before. We have barred owl removal occurring at the Hoopa Valley Tribe, the Yurok Tribe, and there are experiments being done by researchers from other universities, also occurring in the state of California. We have institutionalized barred owl management as part of the Habitat Conservation Plans for both Green Diamond Resources Company and Sierra Pacific Industries. I've heard rumor, which I hope is true, that Humboldt Redwood Company is close to adopting a barred owl management program. It is inspiring to me to be in this area of California where folks like you, folks like Zach Peery, Mark Higley, Keith Hamm, all these people who are actively engaged in barred owl removal are doing the science, doing the hard work.

So, Vitek, thank you so much for all that you do at the Integral Ecology Research Center. Again, you can find Vitek's paper at IERCEcology.org. Thank you for coming on the show.

All right. This has been another episode of the EcoNews Report. Join us next week on this time and channel for more environmental news from the North Coast of California.