Save at-risk owls by culling rivals? Tough choices in US Northwest.

In the 1990s, you couldn’t talk about logging in the Pacific Northwest without talking about the spotted owl. 

The medium-sized, dark-brown owl was at the center of a fierce conflict between the powerful timber industry and environmentalists trying to protect old-growth forests. The owl, which prefers such forests, was barreling toward extinction due to logging and other habitat destruction. 

Environmentalists fought a successful campaign that led to federal protection from logging for millions of acres of forest. But today the spotted owl’s population is still falling rapidly, with continued logging and larger wildfires sharing much of the blame.  

And there’s another culprit: the barred owl that is invading old-growth forests in Oregon, Washington, and California, putting it in scientists’ crosshairs – literally. 

Scientists have spent more than a decade testing whether killing barred owls, which are considered invasive in the Northwest, might prevent the extinction of the northern spotted owl (the subspecies that lives in this region). Research teams led by David Wiens, a U.S. Geological Survey wildlife biologist, released results last May showing that culling almost 2,500 barred owls in Northwest forests helped to stabilize spotted owl populations, which had stopped reproducing after their larger cousins showed up. 

The controversial experiment could become federal policy as the U.S. Fish and Wildlife Service maps out a large-scale management plan in the Pacific Northwest for barred owls. That would represent an official imprimatur for a policy of culling one species – the barred owls – to save another. But it may not be the last as a warming planet stresses ecosystems in ways that threaten disaster for North American birds including the spotted owl. 

Conservationists and animal welfare groups remain torn on the practice of culling barred owls so that their vulnerable cousins survive. Could it be the lesser of two evils? 

“There’s a growing reception to this as a necessary evil,” says Tom Wheeler, executive director of Environmental Protection Information Center, an advocacy group in Northern California. Mr. Wheeler supports expanding the practice to other Northwest forests and is building bridges with other conservationists to ensure that they’re not a roadblock to removing barred owls.  

He will need to convince activists like Kristen Boyles, a managing attorney at Earthjustice, a nonprofit law firm, who has worked for decades on spotted owl issues. Although Earthjustice didn’t legally challenge the experimental cull of barred owls, she says federal scientists are scapegoating barred owls when the real problem is continued loss of spotted owl habitat.  

“Which doesn’t mean that barred owls aren’t a problem, it’s just that they’re not the core problem,” Ms. Boyles says. “If you shoot all the barred owls, and there’s no place for the spotted owls to live, then it doesn’t make much of a difference, right?” 

An Audubon Society report found that two-thirds of North American bird species are at risk of becoming extinct by the end of this century as rising temperatures alter habitats. Bob Sallinger, conservation director at Portland Audubon, warns that will push more species into conflict with one another, spurring ethical dilemmas like the one over barred owl management. 

“We’re very likely to be faced with many, many more of these decisions at a rapid pace,” he says. “I don’t think we have our heads wrapped around that yet. It may require an entire paradigm shift of how we manage wildlife at some point.”

Highly adaptive owls

When biologist Mark Higley began surveying a portion of forest in the Hoopa Valley Indian Reservation in Northern California in 1991, he found two spotted owl couples living there. 

That was likely the same time barred owls arrived here, he says. The species, which is beloved in its native East Coast range, expanded west during the 20th century.

Spotted owls are sensitive: They need old-growth forests and a tailored diet to survive. Barred owls, on the other hand, are a highly adaptive species. They can live in cities, swoop at joggers, and eat virtually “anything that moves and will fit in their mouth,” says Mr. Wiens, the USGS biologist. They’ll enter old-growth forests and aggressively drive away many spotted owls. Those that remain can’t easily reproduce because they stop calling to potential mates for fear of alerting their rival. 

The U.S. Geological Survey estimates that spotted owl numbers in the Northwest plummeted by up to 85% between 1995 and 2017, a period when barred owl populations exploded.

For 20 years, Mr. Higley couldn’t find a single spotted owl in the surveyed portion of the Hoopa reservation until 2013, when the tribe’s wildlife agency began killing barred owls as part of Mr. Wiens’ study. In total, scientists killed almost 600 barred owls on the reservation between 2013 and August 2021.

Mr. Wiens’ team found that in areas where no culls of barred owls took place, spotted owl populations declined by an average 12% each year, putting them on a path to extinction. But when barred owls were hunted, spotted owl populations stayed level. 

Killing in the name of preservation

Land managers often kill species in the name of ecological health, especially invasive species. The brown tree snake, for example, has wreaked havoc on native bird populations in Guam; scientists have tried dropping drug-filled mice in the jungle to kill the snakes, so far without success. 

That approach sometimes hurts more than helps. A case in point is the federal government’s attempt to protect salmon in the Pacific Northwest by killing one of their predators, the double-crested cormorant. The strategy didn’t boost salmon runs, which are threatened by dams, pollution, and warming rivers, but it decimated the bird’s largest colony in the world. 

Mr. Sallinger of Portland Audubon says there are many such examples of land managers creating unforeseen results when culling a species. Portland Audubon is waiting to see the details of the federal government’s barred owl plan before taking a stance, he adds. 

Michael Harris, director of the wildlife law program at Friends of Animals, which sued the federal government unsuccessfully to stop the barred owl cull, says officials are shortchanging a complex problem – declining spotted owl populations – with a “cruel” solution that scapegoats its larger cousin. “I don’t see it as a sustainable solution to the problem,” he says.

Conservationists and animal welfare advocates say that regardless of what happens with the barred owl cull, more critical habitat for spotted owls needs protection. Logging and development has destroyed almost three-quarters of the spotted owl’s old-growth habitat, which can take more than a century to restore. 

In a win for the species, the Fish and Wildlife Service recently moved to protect huge swaths of owl habitat placed on the chopping block in the waning days of the Trump administration. But even that proposal would still shave off 200,000 acres of previously protected habitat. 

Mr. Wiens emphasized that the experiment he led culled only a tiny portion of barred owls in the Pacific Northwest. And while scientists in California are still killing barred owls on public and private lands, the practice is now on hold in Oregon and Washington, pending federal guidance. As a result, says Mr. Wiens, forests are already being “overrun” by barred owls.