In the ancient forests of the Pacific Northwest, the northern spotted owl, a rare and fragile subspecies of spotted owl, is being muscled out of its limited habitat by the barred owl, its larger and more ornery northeastern cousin. The opportunistic barred owl has been moving in on spotted owl turf for more than half a century, competing with the locals for food and space, outnumbering, out-reproducing and inevitably chasing them out of their nesting spots. Barred owls have also emerged as a threat to the California spotted owl, a closely related subspecies in the Sierra Nevada and the mountains of coastal and Southern California.
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.
Karla Bloem, the executive director of the International Owl Center in Minnesota, is conflicted over the prospect of killing one species to protect another. “The concept of shooting birds is awful — nobody wants that,” she said. “But none of the alternatives have worked, and at this late date no other option is viable. Extinction is a forever thing.”
Bob Sallinger, the executive director of Bird Conservation Oregon, agreed but emphasized that the culling must complement the restoration and preservation of the few remaining old-growth forests. “The science clearly shows that you must both protect and increase habitat and remove some level of barred owls if the northern spotted owl is to have a chance of survival,” he said.
The agency’s plan, outlined last fall in a draft report assessing its environmental impact that is due for final review this summer, has pitted conservationists, who say it will benefit both species, against animal supporters, who consider the proposed scale, scope and timeline unsustainable.
Last month, a coalition of 75 wildlife protection and animal welfare organizations sent a letter to Secretary of the Interior Deb Haaland urging her to scrap what they called a “colossally reckless action” that would necessitate a perpetual killing program to keep the number of barred owls in check. Wayne Pacelle, the president of Animal Wellness Action and an author of the statement, said it was dangerous for the government to start managing competition and social interaction among North American species, including ones that have expanded their range as a partial effect of “human perturbations” of the environment. “I cannot see how this succeeds politically, because of its price tag and its sweeping ambitions,” he said in an email.
Mr. Pacelle questions whether barred owls, which are indigenous to North America, truly meet the criteria for an invasive species. “This ‘invasive’ language rings familiar to me in our current political debates,” he said. “Demonize the migrants, and the harsh policy options become much easier from a moral perspective.”
The signatories argued that the current predicament warranted nonlethal control, and that the agency’s approach would lead to the wrong owls being shot and to the death of thousands of eagles, hawks and other creatures from lead poisoning. “Implementing a decades-long plan to unleash untold numbers of ‘hunters’ in sensitive forest ecosystems is a case of single-species myopia regarding wildlife control,” the letter said.
Rocky Gutierrez, a wildlife ecologist who has conducted research on spotted owls since 1980, described the letter as disingenuous. “It is apparent to me that the authors either did not understand the plan or they didn’t read it carefully,” he said. “Secretary Haaland is likely not to be swayed by their arguments because they are often incorrect or based on nonscience.”
Dr. Gutierrez noted that the government draft explicitly forbade lead and other toxic ammunition, and that the agency planned to enlist not hunters but highly trained specialists who would be required to take a course and pass a test.
“Because the training and rigorous protocol minimize the chance for misidentification, there has yet to be a case of mistaken identity,” Dr. Gutierrez said, referring to the results of a five-year field experiment published in 2021. “Several major peer-reviewed studies have demonstrated the efficacy of this removal method.”
Ms. Bloem, of the International Owl Center, added: “Spotted owl research is some of the most rigorous science on earth because so much has been riding on it. This management plan is no exception.”
A spotted decline
The Fish and Wildlife Service has been trying to save the spotted owl for decades. The effort became a cause célèbre in the 1980s as environmentalists saw it as a way to force the U.S. government to drastically reduce logging in northwestern federal forests. The birds depend on old growth woodland to survive, preferring towering trees such as Douglas firs that typically take 150 to 200 years to mature.
Over the passionate objections of the timber industry, spotted owls were listed as threatened under the Endangered Species Act in 1990. As loggers mounted protests, dead owls were nailed to road signs and “owl fricassee” appeared facetiously on restaurant menus. Four years later, the Northwest Forest Plan established a new management framework for the 24 million acres of federal forest land in Washington, Oregon and California within the range of the northern spotted owl. Despite sharp logging cutbacks, the bird’s population decline continued, especially in areas where barred owls were densest.
Barred owls started making their way west in the early 1900s as European settlers transformed the Midwest landscape from prairie to patches of woodland. Aided perhaps by a warming trend in the boreal forests of eastern Canada and northern Minnesota, where barred owls are abundant, the birds spread across the Great Plains and, by 1943, were spied in British Columbia, the domain of the northern spotted owl.
“When spotted owls were listed in 1990, it was known that barred owls could be a potential threat,” said David Wiens, a wildlife biologist with the U.S. Geological Survey. “But we knew very little about barred owls then, and had no idea what their population trajectory would be in the Pacific Northwest.”
At first sight, it’s easy to mistake a spotted for a barred: Both have tuftless rounded heads, teddy bear eyes and bodies mottled brown and white. They can interbreed to produce chicks called sparred owls. But they differ in their habitat requirements. Up to four pairs of barred owls can occupy the three-to-12 square miles that one spotted couple needs, and barred owls aggressively defend their terrain. “The closer spotted owls live to barred owls, the less likely the spotted owls are to have offspring,” Dr. Wiens said. Barred owls also produce four times as many young.
Spotted owls are extremely picky eaters: In California, they eat only flying squirrels and wood rats. “Barred owls devour anything and everything,” Ms. Bloem said, “which is hard on Western screech owls, rare reptiles and amphibians, and has cascading effects on the ecosystem.”
‘No one wants them’
Some animal activists have suggested that rather than shoot the barred owls, the Fish and Wildlife Service should try to stop them from reproducing. But Eric Forsman, a retired Forest Service biologist whose research informed the Northwest Forest Plan, countered that every other option had already been on the table. “Half-baked methods like sterilization and egg removal would be impossible at the scale needed to reduce numbers,” he said.
Another nonstarter is relocation, which would risk introducing new parasites and diseases from the West into the barred owls’ historical range. “If people complain about the cost and feasibility of 15,000 birds removed per year, the price tag for translocation would probably send them into cardiac arrest,” Dr. Gutierrez said. “And besides being too time-consuming, where would you relocate the owls to? No one wants them.” You could “let nature take its course,” he added, but that course would be extinction for the spotted owl.
Three years ago, researchers published the results of a pilot program that involved discreetly culling 2,485 barred owls in five study sites along the West Coast. The birds were lured with recordings of their calls, which cause spotted owls in the wild to retreat and remain silent to avoid detection.
Dr. Wiens, who helped run the experiment, said that over five years of culling barred owls halted declines in the spotted owl population; in areas without removal, spotted owl populations fell by about 12 percent annually.
Ms. Bloem offered a “successful precedent” for the government’s owl scheme. In the 1970s, an effort by the Fish and Wildlife Service to trap brown-headed cowbirds in Michigan saved the Kirtland’s warbler from extinction, though the warbler’s population did not increase for almost 20 years after trapping began.
“If efforts are focused on the leading edge of the barred owl invasion in California and in the few remaining pockets in Washington and Oregon, continued annually or every few years, there is a reasonable chance for this to work,” Ms. Bloem said. She added that the best hope was for the California spotted owl, which has not been so thoroughly infiltrated yet.
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.”
Source link: https://www.nytimes.com/2024/04/29/science/california-barred-spotted-owls.html