Animal Forecast

Owl vs. Owl

Should the government shoot the spotted owl’s new enemy, the barred owl?

Northern Spotted Owl (Strix occidentalis caurina) at the Oregon Zoo, 2006.
Northern Spotted Owl (Strix occidentalis caurina) at the Oregon Zoo, 2006

Photo by Cacophony/Wikimedia Commons.

Big-eyed and sweet-faced, the spotted owl may be the most controversial bird in the country. And possibly the unluckiest. Twenty years ago, it was a national symbol for one of the defining environmental battles of the 20th century—the fight over whether to log or preserve old-growth forests of the Pacific Northwest.

Now the spotted owl faces a new and even more desperate battle, one that has it staring straight into the face of extinction. The new threat comes not from people but from an invasion of its own cousin—the aggressive and highly adaptable barred owl—into the spotted owl’s last territories.

The future for spotted owls currently looks so bleak that wildlife managers in the Pacific Northwest have proposed a desperate plan: They want to kill thousands of barred owls. British Columbia approved plans last week to shoot barred owls within 5 kilometers of spotted owls. The U.S. government may not be far behind.

“It’s a vanishing sight, rarer and rarer,” said Dale Herter. We were standing 10 feet away from a spotted owl on a steep slope near Mount Rainier. Herter is a biologist who has studied spotted owls in the Cascades for 22 years and has documented the owl’s accelerating decline.

This spotted owl, a female, looked at us with her huge, darkly luminous eyes. Prominent facial disks, the wide circle of feathers around the eyes, add to the bird’s sense of openness and curiosity. Spotted owls are famous for their approachability, friendly charm, even tameness. They often fly close to people in the forest and perch placidly nearby.

“They could all be gone in a decade or two,” Herter said. Then he added in an ominous tone, “unless we kill all the barred owls.”

On June 26, 1990, the northern spotted owl was listed as threatened under the Endangered Species Act. Several studies had clearly linked the spotted owl’s decline to the logging of old growth forests in the Pacific Northwest. Much more research followed, making the spotted owl one of the most intensively studied birds in the country. And the research has affirmed and illuminated the species’ heavy dependence on towering old-growth forests.

The listing ignited a controversy that reached all the way to the White House. President Clinton called for a forest summit that led to the 1994 Northwest Forest Plan, protecting both the owl and the region’s spectacular old-growth forests. By that point, 80 percent of the former old-growth territory had been destroyed. Annual timber harvests dropped from 5.6 billion board feet in the 1980s to about 526 million board feet in 2004.

Loggers complained bitterly about the spotted owl, but the truth is, even without the additional scrutiny and protections brought on by the Endangered Species Act, harvesting at previous levels was no longer sustainable. People had been logging trees that were hundreds or thousands of years old, and these are slow-growing species. Clear-cutting—taking out every tree in an area—had nearly wiped out the forests on unprotected lands. There just weren’t that many trees left to log.

But despite the protection of their remaining habitat, the spotted owl population continued to decline, by about 3.5 percent per year. In Washington, where ranges are bigger, they’re declining faster, at 7.5 percent per year. The rate has been slower on federally protected forests, but the overall trend is ominous, unmistakable, maybe inescapable.

On the Olympic Peninsula, for example, there were 150 spotted owls in 1992. In 2009, just 13. In Dale Herter’s study area in the Cascades, there were 127 owls in the 1990s. Now, he says, there may not be that many in the whole state of Washington.

The new threat comes from the barred owl, which has moved into the Pacific Northwest and become a neighborhood bully. The species was once found only in the East, but over the past several decades, barred owls made their way across the prairies. The first barred owl was reported in Washington in 1965. In Oregon, 1974. In California, 1981. No one is really sure why they came. They may have crossed the prairie by using human-altered landscapes—managed forests, suburbs—as stepping stones across once-inhospitable grassland. Once they arrived in the West, some research suggests that they first took hold in logged areas and then spread to other habitats.

Though they are members of the same genus of owl—Strix—the two species are very different, like spots and stripes. The spotted owl is friendly, slow to reproduce, and tragically limited to a narrow ecological niche of old-growth forests.

The barred owl is a supremely adaptable generalist. It’s also a feisty breeding machine. Barred owls have been seen chasing spotted owls out of their territories, even attacking them. Then they take over.

Eric Forsman is the pre-eminent spotted owl biologist. His studies in the 1970s showing population declines and tying them to the birds’ reliance on old-growth forest catapulted the owl into national headlines. When he established his study site in Oregon’s Coastal Range, there were no barred owls. A recent study of the same site found 82 pairs of barred owls and only 15 pairs of spotted owls.

“Lots and lots and lots of ’em,” Forsman said, referring to barred owls throughout the Pacific Northwest. Biologists are convinced they’re a major competitive threat to spotted owls.

In what may ultimately be a Quixotic effort, the U.S. Fish and Wildlife Service has designed an experiment to “remove”—which basically means to shoot—barred owls from up to 21 selected areas to see if spotted owls then return.

“It’s a study, an experiment,” Robin Bown emphasized to me. She is the USFWS team leader for the project. “We want to know if removal of barred owls is even a viable management option,” she said.

A decision is due soon, perhaps this winter, on which of seven options the USFWS will choose. The most aggressive option would kill 8,953 barred owls. As Dan Ashe, the director of USFWS, put it, “We have a clear obligation to do all we can to prevent the spotted owl’s extinction.”

It’s easy to understand the desire to save the beloved and beleaguered spotted owl. Yet many people have reservations about whether and how to perform the experiment. Despite devoting his professional life to spotted owls, Forsman pointed out that, “to work, we’ll have to kill thousands of barred owls forever.” Then he added, “We should not kid ourselves. To kill barred owls to answer a scientific question when you won’t use what you learn to solve a problem, well, it’s an ethical struggle.”

Spotted owls may face another big challenge, from climate change. Warmer, wet winters and springs hurt young owl survival rates, and drier summers mean the small mammals that spotted owls eat are less abundant. Most climate change models suggest that the Pacific Northwest will experience just those conditions. That means lower population growth rates for spotted owls—or an even faster decline.

I recently visited a family of barred owls on Bainbridge Island near Seattle. Barred owls first arrived on the island in 1992. Now they’re everywhere. I found a mom and her two babies in a maple tree, huddled on a mossy branch. This particular mom produces two to three babies per year. One of her banded babies from an earlier year was found 100 miles away, on the Olympic Peninsula. It’s hard not to admire such powerful and successful birds.

Then I remembered the female spotted owl I’d seen on Mount Rainier, who may produce only one owlet every other year. What’s her future?

We’re left with a terrible choice, one that pits two handsome, charismatic, and incompatible species of owl against each other. It speaks to the complexities, and maybe also the limits, of what our management of nature is able to do.

Correction, Feb. 5, 2013: The sub-headline for this story originally asked whether the Forest Service should shoot barred owls. The responsibility for shooting them rests with the U.S. Fish and Wildlife Service.