Spotted owl's diminishing numbers have some fearing species is doomed

Article Date: 2008-08-24   Source: http://www.cleveland.com   Comments: 0

By Warren Cornwall

Seattle, Washington, U.S.A. - The northern spotted owl - an endangered icon that 14 years ago spurred a rescue effort so sweeping it brought old-growth logging to a virtual standstill in the Northwest - is now closer than ever to extinction.

While there is disagreement over how bad it could get, some are contemplating the virtual disappearance of a bird elevated to sainthood by environmentalists and hung in effigy by loggers.

The situation is particularly bad in Washington, where the rate at which owls are found at nesting sites has fallen by nearly half since 1994. Scientists blame the decline largely on the invasion of a tougher owl and the loss of much of their habitat to decades of logging.

 "The populations seem to be gradually going downhill, and it's not clear if or when that's going to stop," said Eric Forsman of the U.S. Forest Service, a pre-eminent spotted-owl scientist. The birds' decline is forcing a rethinking of long-held strategies to save them. Ideas under consideration include shotgunning one owl species to save another.

Back in 1994, few could have foreseen things turning out this way. The Clinton administration - spurred by lawsuits, the listing of the owl under the Endangered Species Act and years of political upheaval over Northwest logging - set aside 24.5 million acres of federal forestland as a haven for the owls.

The Northwest Forest Plan was supposed to set the stage for recovery of the football-size bird, which favors older forests because it nests in the cavities of big trees and eats forest-dwelling creatures such as flying squirrels.

But the recovery hasn't happened. It's unknown exactly how many spotted owls there are. Scientists take the bird's pulse by monitoring huge patches of forest from Washington's Cascades to Northern California. In every place, there are more empty nests today than in 1994.

"Within a decade we may not have any in Washington unless they do something," said wildlife biologist Dale Herter.

The magnitude of the problem was confirmed by a new analysis of spotted-owl genetics.

With little fanfare, federal scientists in July publicly released a study warning that northern spotted owls, particularly in Washington, have reached a "population bottleneck."

 The remaining birds are genetically similar enough that there is a heightened risk of inbreeding, the study found. The bottleneck also threatens the genetic diversity that helps a species adapt.

It's not clear if this is already a reason owl populations are falling. But the authors said we could be witnessing a bird in a downward spiral exacerbated by a shrinking gene pool, known as an extinction vortex.

Scott Gremel points the finger at one chief culprit for what he has witnessed in Olympic National Park: the barred owl, which is bigger, more versatile and able to hatch more offspring than the spotted owl.

 Clear-cutting of trees hasn't threatened owls in the park's protected forests. Yet their numbers keep dropping as barred owls move into valley after valley. Last year just 37 percent of the places in the park where spotted owls once nested were still occupied by the birds.

Across the West Coast, the barred owl is a prime suspect in the spotted owl's disappearance. Native to the East Coast, it's thought to have reached the West Coast in the mid-1900s via forests in Canada. But it wasn't until the 1960s and 1970s that they first were seen in Washington and Oregon. In the last two decades, their numbers have exploded.

Spotted owls are also vulnerable to harsh winters, loss of old-growth habitat to forest fires, and continued logging. Some of the decline might be an aftereffect of logging on federal lands in the 1980s. But a handful of studies and scientists' repeated stories of barred owls harassing spotted owls all suggest the barred owl is taking a toll.

Desperate government wildlife managers are now considering experiments of systematically shooting barred owls.

But Forsman, of the Forest Service, has his doubts. "You could shoot barred owls forever, and as soon as you quit, they're going to be right back."

Related Articles:
2010-09-02 - Judge orders government to revise plan to protect northern spotted owls by Eric Mortenson - Seattle, Washington, U.S.A.
2009-04-02 - Spotted-owl recovery gets another look from Obama administration by Warren Cornwall - Washington, DC, U.S.A.
2008-08-13 - As spotted owl's numbers keep falling, some fear it's doomed by Warren Cornwall - Washington, U.S.A.
2007-04-26 - Environmentalists say feds trying to weaken spotted-owl forest plan by Warren Cornwall - Seattle, Washington, U.S.A.
2006-11-14 - Seattle activists sue to stop logging - Seattle, Washington, U.S.A.
2005-11-08 - Audubon Society Sues Over Spotted Owl by Gene Johnson - Seattle, Washington, U.S.A.
2004-12-09 - Urban nature: Owls go to town in search of fall food by Maria Dolan - Seattle, Washington, U.S.A.

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