Tweets,

this may be old news for some of you, but not to me, so I thought I'd pass
it on.

New spotted owl threat: Another owl

By Nancy Vogel
Bee Staff Writer
(Published March 4, 1998)
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 U.S.
Endangered Species Act, or whether the hybrid offspring of the two
species 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 with characteristics of both species," he said, "or it could be
that both species sort of work things out and coexist."

"To me it's not that surprising to see this sort of thing happen,"
Forsman said, "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 northern spotted owl -- symbol of ancient
forests to some and, to others, a symbol of environmental rules 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 timber harvesting 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.
Others, such as one in Trinity and Humboldt counties, appear stable.

"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
and Alberta. But since the 1940s they've spread into southwestern
British Columbia, western Washington and Oregon. The barred owl was
first spotted in California's Del Norte County in 1981.

They're most numerous in British Columbia, at the northern edge of the
spotted owl range, where Douglas fir gives way to silver fir.

"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. As of last September, there had
been 291 sightings of barred owls at 59 different sites in California,
said Gould. An estimated 2,000 northern spotted owls live in California.

It could be, said Forsman, that the barred owl filled a particular niche
in British Columbia and won't easily oust spotted owls farther south.

But barred owls are generalists compared with 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,
said Forsman.

Such interbreeding is nothing new in the bird world, said Rocky
Guitrrez, a wildlife management professor at Humboldt State University.
The Mexican duck of the Southwest, for example, was erased from the U.S.
Endangered Species Act in 1978 because of hybridization with mallards
attracted south by farm ditches and dammed lakes.

And once there were two distinct species of flickers, a type of
woodpecker. As people colonized the Great Plains, planting trees and
suppressing fire so that forests developed along rivers, the
yellow-shafted flickers of the east merged with the red-shafted flickers
of the west. Now some flickers have both red and yellow tails, said
Guitrrez.

Woodlots, urban forests and riverside groves could be the same stepping
stones barred owls used to cross the prairie, he said.

"It's only been in the last 50, 60 years that they've hit the Rockies
and come down," said Guitrrez. "If conditions hadn't been altered, why
wouldn't they have done that on their own earlier?"

Barred owls do more than compete with spotted owls for food and nesting
sites, said Guitrrez. One afternoon last May, one of his researchers
found a freshly killed spotted owl in Redwood National Park. An agitated
barred owl hooted nearby, mottled owl feathers stuck to its talons.

But such predation is probably rare. Spotted owls are "mean suckers,"
too, Guitrrez said, that don't hesitate to attack great horned owls.

"My guess is the barred owl is always going to be a low-level effect on
the spotted owls," said Guitrrez, "and they'll adjust to it."

Copyright 1998 The Sacramento Bee