"What price growth...?" |
Spotted Owl faces new enemy: The bigger; meaner Barred Owl
By Nancy Vogel, Scripps-McClatchy Western Service
SACRAMENTO, Calif. - There's a bigger, stronger, meaner owl moving into the forests of the Pacific Northwest, and biologists can only wonder what it will mean for the northern spotted owl.
Barred owls, once found just east of the Rockies, have shifted west in the last few decades. Along the way they've displaced, bred with and even killed outright the northern spotted owls that officials have tried to protect, at great cost to the Northwest's timber economy, since 1990.
First documented in California in 1981, barred owls have been spotted as. far south as Yuba and Nevada counties in the Sierra, and Sonoma County in the Coast Range.
Scientists speculate that humans drew the barred owl west when they planted trees on the Great Plains. It's a head-scratcher to ponder whether the barred owls pose a "threat" to spotted owls under the Endangered Species Act, or whether the hybrid offspring of the two fall under its protection.
"It's potentially one of the most interesting ecological situations that we're going to see," said Eric Forsman, an Oregon U.S. Forest Service researcher who started studying spotted owls in the 1970s.
"It could lead to complete elimination of one species, or creation of a hybrid species ... or it could be that both species sort of work things out and coexist."
Forsman said the situation is not surprising, "but in this case we've got one species that we're very concerned about - it's listed. who knows where it's going to lead?"
But scientists agree on one thing: It wouldn't do much good to try to stop it by hunting barred owls.
"We are part of the ecology," said Gordon Gould, California Department of Fish and Game biologist. "We change the ecology. This is what we have to expect."
Few outside of ornithology circles would notice the barred owl expansion if it didn't affect the spotted owl - symbol of old-growth forests to some and, to others, a syrnbol of environmentalism run amok.
In the 1980s environmentalists looked to dark-eyed spotted owls as a tool to protect forests in Washington, Oregon and Northern California. It was believed the owls need the tree size and structure that forests don't attain until they're nearly 200 years old. Ninety percent of such old-growth forests are gone, experts say.
The owl's federal listing in 1990 triggered a ban on logging in national forests that pitted loggers against environmentalists. President Clinton tried to broker peace with a 1993 plan that slashed harvest on federal lands in the Pacific Northwest by 75 percent and gave timber-based. communities $1.2 billion in aid.
Since then, scientists say, some spotted owl populations have declined.
"Trees don't grow that fast"' said Forsman, "so it's highly unlikely you're going to see a dramatic response in a five-year period when you implement a plan like the Clinton forest plan."
A century ago, barred owls didn't live much farther west than Montana. But since the 1940s they've spread into southwestern British Columbia, Western Washington and Oregon.
They're most numerous in British Columbia, at the northern edge of the spotted owl range.
"These days," said Forsman, "if you go up to British Columbia, you find 10 barred owls for every one spotted owl." The owls are less common to the south, and most rare in California.
It could be, said Forsman, that the barred owl filled a particulat niche in British Columbia and won't easily oust spotted ow's farther south.
But barred owls are generalists compared to spotted owls. They're found in old-growth redwoods and cut-over forests, too. They're bigger and more aggressive and thus able to eat a wider range of prey.
The two species look a lot alike, except that vertical streaks mark the lower breast of barred owls where spotted owls are mottled.
It's not common, but spotted owls and barred owls do mate with one another and produce fertile hybrids that look like a big spotted owl.