Article in the4 NY Times today. I hope this link works — I’m allowed to “gift” articles….
They Shoot Owls in California, Don’t They?
An audacious federal plan to protect the spotted owl would eradicate hundreds of thousands of barred owls in the coming years.
Excerpt:
Crammed into marginal territories and bedeviled by wildfires, northern spotted owl populations have declined by up to 80 percent over the last two decades. As few as 3,000 remain on federal lands, compared with 11,000 in 1993. In the wilds of British Columbia, the northern spotted owl has vanished; only one, a female, remains. If the trend continues, the northern spotted owl could become the first owl subspecies in the United States to go extinct.
In a last-ditch effort to rescue the northern spotted owl from oblivion and protect the California spotted owl population, the U.S. Fish and Wildlife Service has proposed culling a staggering number of barred owls across a swath of 11 to 14 million acres in Washington, Oregon and Northern California, where barred owls — which the agency regards as invasive — are encroaching. The lethal management plan calls for eradicating up to half a million barred owls over the next 30 years, or 30 percent of the population over that time frame. The owls would be dispatched using the cheapest and most efficient methods, from large-bore shotguns with night scopes to capture and euthanasia.
I’m with Eric on this:
“Dr. Forsman is less sanguine. He feared that attempts to control barred owls were likely to fail, because the bird’s range expansion was too extensive. To him, the proposed policy is a call for action based on the “untestable” hypothesis that humans were responsible for the expansion.
If we were not responsible, would we still be making the same call for action? he wondered. “Or even if we were, is there some point at which we simply admit that we have screwed things up so badly that there is no going back to the good old days?” he said. “I am torn apart by this dilemma, and I find it difficult to get mad at anyone on either side of the argument.””
As the evolutionary biologist at TSW, I am going to go out on a limb of potential heresy here and say extinction and speciation are both part of evolution. Some evolutionary “choices” such as specialization come with risks as conditions change.
1. Can we do it? Probably not without massive infusions of resources, potentially forever.
2. Should we do it? What are the trade-offs for other uses of the funding? I’d say something that helps a species get over a hump (say translocation) is a better bet than “messing with something forever”. Also are we planning to do this for all species that are losing out to other species?
Eric brings up the question of whether humans influenced this. We can’t really know, can we, for sure. We can’t rerun the experiment without Indigenous and later immigrants. Then there are studies like this https://forestpolicypub.com/2021/07/25/did-barred-owls-move-into-western-forests-in-the-last-century-new-genetic-evidence-suggests-not/
As I said in that post:
These findings on evolutionary and demographic history of BOs are also important for conservation of SOs since little was known about the history of their “invasive” species, BOs. So far, it has been believed that the habitat loss in the eastern part of the North America caused the migration of BOs to the west. But if BOs have lived in Canadian forests for a long time, their recent invasion to the range of SOs might be due to different reasons, such as the recent loss of boreal forests caused by the climate change and human activities (Gauthier et al. 2015).
Or perhaps they started moving south during the Little Ice Age (1800s) and it took awhile? Lots of possibilities. And we might be collecting data on, and arguing about, the answer, farther into the future than any investment we would be making in controlling barred owl populations.
It would be ironic if Homo sapiens, who hybridized with and displaced Neanderthals (are we the Barred Owls of the hominids?) determined that other species shouldn’t have the have the same prerogatives.
“For one reason or another, the ancestors of modern humans in Africa start expanding in population, and as they expand their range, they meet with these other hominins and absorb their DNA, if you will.”
I think it is important to understand that barred owls do not share the same niche as NSO. NSO rely on flying squirrels, woodrats and voles; while BOs are a prey generalist and recent studies are finding that BOs are devouring large quantities of everything they can get their mouths on (amphibians, rodents, and inverts). You can also pack in 4 BO territories into a single NSO territory. While we have good data on the effects of BOs to NSO, because there are long-term demographic studies on NSO, the effects of BOs on other species are unknown. Yet, it is likely there are far reaching ecological implications of BOs and other reasons to manage barred owls than NSO persistence.
The ESA does not include the ability of the Services to stop managing for NSO until extinction is determined. If it were a possibility, who should get to decide to let NSO and CSO go extinct? There are many listed species that are management reliant due to invasive species. If it’s too late for NSO, does that mean it’s too late for anything for which an entrenched non-native invasive species is the primary threat?
Examples of “listed management reliant species due to invasive species” would be useful for Andy’s question below. They may not be extinct yet, but if they are listed, they are on the way.
A. I don’t think we know that barred owls are “invasive” depending on the definition. We know that they are currently more successful at competing, perhaps because they are generalists. I don’t know who should decide, but I think the idea that the world can afford to create a kind of Disneyland of species that aren’t making it on their own- with enough technology and investment- forever and ever (and remember we are the sixth mass extinction (!) to some) does not seem realistic.
Barred owls moving west at the same time humans expanded west is quite a coincidence. Sure, we may have witnessed a massive natural range expansion and the unification of two species that have been separated for thousands of years, but I find that to not be the most parsimonious explanation.
Found a paper on barred owl migration. Paywalled, but here’s the abstract:
“Range Expansion of Barred Owls, Part I: Chronology and Distribution”
https://www.jstor.org/stable/20491416
During the past century, Barred Owls (Strix varia) expanded their range from forests east of the Great Plains to forests throughout most of central and western North America. Here in Part I, I map more than 12,500 records of Barred Owls in their expanded range from the earliest records to the present, draw the species’ distribution in its expanded range and infer the general timing and flow of the range expansion. Evidently, Barred Owls originally traveled across the northern Great Plains via the forested riparian corridors of the Missouri, Yellowstone and Musselshell rivers into east-central Montana by 1873. From there, they accessed western forests in southwestern Montana (1909), moved to northwestern Montana (1922) and then expanded their range in two general directions. They moved north and east to northern Alberta (1934) and Saskatchewan (1948) where they apparently encountered other Barred Owls coming westward from Manitoba. They also moved north to northern British Columbia (1943), southeastern Alaska (1967) and Northwest Territories (1977), and west and south to Washington (1965), Idaho (1968), Oregon (1972) and California (1976). In Part II (Livezey, in press), I explore what prevented Barred Owls from expanding their range westward during recent millennia and what allowed them to do so during the past century.
Hmmm. Barred owls have been on the west coast since the ’60s without being an obvious problem. What happened after that that allowed them to expand within that extended range at the expense of spotted owls? Maybe it had something to do with liquidating old growth?
See Appendix 1, starting on page 197, for a thorough review of the literature on BO range expansion and potential causes:
https://www.fws.gov/sites/default/files/documents/Final%20draft%20Barred%20Owl%20EIS.pdf
A. Thanks for this.. I note there seem to be two hypotheses the Central and the Northern ” Northern Boreal Forest Potential Route Treeline along the southern edge of the Northern Boreal Forest was affected by the same factors
listed above. Extensive tree planting/forest expansion and both direct and indirect fire exclusion/suppression by settlers occurred at the southern edge of Northern Boreal Forests in Canada (Livezey 2009b, p. 327-336).
Conditions within the Northern Boreal Forest have likely changed with the early effects of climate change. There has been a general warming trend since at least 1860 in Canada, including in the Northern Boreal Forest. This warming trend may have begun at the end of the last mini-ice age, but likely increased as a result of anthropogenic factors resulting in an increase in greenhouse gases in the atmosphere (Campbell et al. 1993, p. 336; Gullett and Skinner 1992, entire; Schindler et al. 1998, p. 157-158). The period from the late 1800s through the 1940s
experienced a pronounced warming trend in Central Canada especially in the Northern Boreal Forest and Canadian prairie, with the 1930s to 1940s being particularly warm. (Shindler et al. 1998 p. 157-158; Gullett and Skinner 1992, entire). While the Northern Boreal Forest structure
did not substantially change as a result of climate changes in the past 100-150 years (Campbell et al. 1993, p. 336-337), small changes in the general or extreme temperatures may have allowed barred owls to survive and reproduce in the southern portion of the Northern Boreal Forest where they had not previously existed.” I note that the genetics study I cited here leans toward the “down from the north” view. I also note that that study wasn’t cited in the EIS. https://forestpolicypub.com/2021/07/25/did-barred-owls-move-into-western-forests-in-the-last-century-new-genetic-evidence-suggests-not/
I wrote the authors of that study to see if they had updated info.
I’d like to ask the evolutionary biologist if species ever expand into new territories without something having changed – in particular something that changed in the habitat of new territory (though I suppose it could sometimes be a change in the species that allows it to adapt to habitat that it couldn’t occupy before). Nowadays, any changes in that new territory are likely to be human-caused.
I guess it depends on what you think of as “new”- right now grizzlies are heading out to the plains in Montana and wolves moved from Wyoming down to Colorado. Conditions are always changing. The climate has been changing since glaciation, so trees have been moving back from refugia.
The grizzly bear and wolf range expansions are human “caused.” The Endangered Species Act modified human behavior that was preventing that expansion. It’s not “new” – they were there before we were.
Sure there are natural changes in habitat, but I think it’s pretty obvious that for most species the effects of that are dwarfed by what we have done. I would tend to believe that is true for barred owls.
Well, you could argue that humans influence everything on the earth via climate change.. and how could anyone prove that some change does not have a human component? .. and yet.. systems were dynamic while primates were still in trees.
Look at land cover change maps, such as the Willamette Valley, and the non-climtae human caused changes far exceed any climate impacts, so far.
Homo sapiens.
High Country News has an article on this:
Killing one owl to save another
Is it ever the right thing to do? Two ethicists weigh in.
https://www.hcn.org/articles/killing-one-owl-to-save-another/
Excerpt:
This fall, the agency proposed a radical solution: killing nearly half a million barred owls in Oregon, Washington and Northern California over the next 30 years. The plan has divided conservationists; some say it is the only way to save the northern spotted owl, while others question both its ethics and its effectiveness. For some perspective, High Country News spoke to William Lynn of Clark University and his colleague Francisco Santiago-Ávila of Project Coyote. Specialists in animal ethics, both Lynn and Santiago-Avila have followed the controversy closely, and Lynn led the ethics review for a barred owl removal experiment that the Fish and Wildlife Service conducted from 2013 to 2020. This interview has been edited for length and clarity.
“We’re, of course, largely responsible for the decline of the spotted owl, because we’ve transformed the habitat through logging, so I would say humans are responsible for reversing its decline.” If we use that same argument, “species are in trouble and its our fault” and apply it to climate change.. then every decline is “our fault” and therefore we are responsible for managing every species decline in perpetuity. Remaking the world into a 1880s Disneyland without the Native Americans.
I don’t mind if people want to do such things, say restore American Chestnut, but should the USG fund them (conceivably at the expense of other priorities?). Then there’s the whole aspect of not just giving a species a leg up (say black footed ferret) but actively killing related birds?
Yes, that’s a pretty good summary of how the Endangered Species Act addresses species decline. But you left out the “God Squad” section that provides for high level oversight and exceptions to allow declines based on some kind of “cost/benefit” analysis.
Actively restoring (“remaking”) things is a little different from stopping declines, and is not the spotted owl situation. (Black-footed ferret recovery requires killing fleas that infect prairie dogs with plague.)
Glad you pointed that out about the fleas..I think because we are human, perhaps we are more sympathetic to barred owl deaths than flea deaths. Especially since they are vectors of a disease that killed many humans. It would be interesting to ask that question of the two ethicists.
I enjoy playing around with ChatGPT-4 (yes, I’m even a subscriber 😬). I asked AI if northern spotted owls stop hooting in response to survey calls when in the presence of barred owls. AI acknowledged that fact was well-established. So I followed up with this question:
Andy Stahl
Could this survey challenge be so great that northern spotted owl surveys understate the owl’s population status and overstate its downward trend?
GPT-4
Yes, the challenge of accurately surveying northern spotted owls in the presence of barred owls can potentially lead to an underestimation of their true population numbers and an overstated perception of their decline. This issue arises because of several factors:
Reduced Responsiveness: As previously mentioned, northern spotted owls may decrease their vocal responses to standard survey calls when barred owls are nearby, to avoid conflict or because they have been displaced from their preferred territories. This reduced responsiveness can lead to an undercount of actual individuals during surveys.
Survey Biases: Traditional survey methods, such as audio playbacks, are designed based on the assumption that owls will respond to calls if they are present. If these methods are less effective in detecting spotted owls due to their altered behavior around barred owls, the surveys may not accurately reflect the population’s status.
Geographic Displacement: If barred owls displace northern spotted owls from prime habitats to less ideal, unmonitored areas, the owls may still exist, but outside the surveyed regions. This displacement could lead to inaccuracies in understanding the full distribution and population size of the species.
Impact Misinterpretation: The influence of barred owls on spotted owl behavior could lead researchers to interpret a lack of responses as a sign of population decline rather than an adaptation to coexistence with barred owls, potentially misrepresenting the survival and health of the population.
Is AI hallucinating or are barred owl assassins over-confident that they’re making a positive difference?
PS: I’ve been intrigued with this matter for some time. Several years ago I posed this question to population geneticist Russ Lande (winner of a MacArthur genius award for conservation modeling inspired by his seminal spotted owl population analysis): “Is there a confirmed case of inter-species competition for food and territory causing the extinction of one of the protagonists?” Russ couldn’t think of one. I invite readers to respond.
Did you ask ChatGPT that question?
I did. ChatGPT cited three examples of a closely-related invasive species competing with indigenous relatives; however, none resulted in indigenous extinction. “While these examples do not result in the total extinction of a species, they highlight significant declines and displacements caused by competition. In some cases, if not managed or mitigated, such competition could potentially escalate to extinction, especially in limited or isolated environments. The impact of invasive species on native biota is a critical issue in conservation biology, often leading to significant ecological changes and the decline of native species.”
Russ opined that the indigenous critter eventually reaches a new demographic equilibrium, albeit at a smaller population. Of course, a smaller population can be more susceptible to noncompetitive extinction pressures, e.g., biogeographic declines caused by difficulties in finding mates and/or unoccupied nesting habitats.
or inbreeding depression. OTOH BFFs seem to be recovering after a bottleneck
“Black-footed ferrets have a limited gene pool because all living ferrets today are descendants of just seven wild-caught individuals. This means that contemporary individuals are related to each other as closely as a sibling and a first cousin, which has led to malformities like kinked tails and deformed sternums.”
Perhaps Russ has more confidence in the abilities of organisms to adapt than when we pop geneticists relied on models.. Since I worked at the time with the Corn People with maize still having genetic variability after many years of breeding, I thought that there was more to genetic variability than accounted for in our old pop gen models.
Russ is first-and-foremost a theoretical population geneticist — one of the world’s best. So I was surprised to learn that he didn’t think inbreeding is a common cause of species extinction. As readers may recall, it was inbreeding concerns that led the Forest Service in the 1980s to propose that 500 pairs of spotted owls were sufficient to avoid extinction. Oregon Public Broadcasting’s Timber Wars tells that story well.
Russ’s analysis showed that the demographic effects associated with habitat loss were a bigger threat to the NSO’s survival. That much hasn’t changed.
Surveys are now frequently done with passive monitoring and there is a high probability of detection in the presence of barred owls (which is everywhere in the range of NSO):
https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.4421
https://www.fs.usda.gov/pnw/pubs/pnw_rp618.pdf
Andy, that’s a good question. But I think we need to think about genetic swamping as well as inter-species competition for food and territory. Think of the Neanderthals, and other extinct hominims. Are they really extinct, or do they live on in us? Does that count as extinct? https://www.nhm.ac.uk/discover/news/2022/october/neanderthal-extinction-maybe-caused-sex-not-fighting.html
So we can imagine two different possibilities… competition for food and territory alone (what you posit) and
competition (of some kind) plus introgressive hybridization (less value-laden than “swamping) like Neanderthals (which we didn’t know about before today’s genetic study capabilities).
There are documented cases according to Defenders https://defenders.org/blog/2022/12/five-drivers-of-extinction-invasive-species#:~:text=Invasive%20species%20can%20cause%20the,extinct%20thanks%20to%20invasive%20species.
of invasive species leading to extinctions (seems like mostly by being eaten directly). Are barred owls, invasive though, or still moving south from post-glaciation refugia? If the climate warms and Doug firs move out of Oregon, will their likely pine replacements be invasive? How do we define invasive..(1) “wasn’t there in 1880″ or (2)”moved by humans” or (3) “came because of conditions influenced by humans”? Seems like we could hazard a guess at 1 and 2, but since humans have many influences, it would be difficult or impossible to tell.
Remember, also, that northern goshawks compete with spotted owls for nesting habitats. Many of the concerns about barred owls also apply to goshawks. Maybe we can train the goshawks to hunt the barred owls? *smirk*