Owls Face Spotted Future
Sharon Guynup and Nicolas Ruggia
National Geographic Channel
|July 22, 2004|
A northern spotted owl swoops down silently from its roost high in a
mammoth redwood tree, zeroing in on the unsuspecting rodent below. It
is a rare sight. Despite their 1990 listing under the Endangered
Species Act (ESA), these once-abundant nighttime raptorsa
necessary check in the balance of these Pacific Northwest
forestsare becoming ever scarcer.
"The most recent analysis we did suggests that overall, the population is declining," said Eric Forsman, a wildlife biologist at the U.S. Forest Service's Pacific Northwest Research Station in Corvallis, Ore. and an author on the new report.
This assessment found that over the past decade, spotted owl populations have dropped by roughly half in Oregon's Warm Springs Reservation and parts of Washingtonand by almost a quarter along parts of the Oregon coast and Cascade Mountains. Their numbers remained stable in just a few areas.
Loss and fragmentation of the owls' old-growth forest home was one of the reasons for ESA listing. Over the last two centuries, an estimated 80 percent of old growth forests have been logged from Northern California to British Columbia.
Save a Logger, Eat an Owl
The high commercial value of old-growth timber put the spotted owl at the center of one of the most contentious environmental debates in U.S. history: jobs versus owls. During the late 1980s and early 1990s, a series of public, political, and legal controversies created hostilities in many small Pacific Northwest communities.
"Save a logger, eat an owl" became a popular slogan in logging towns, and some local restaurants even served spotted owl barbeque. Forest activists camped out for months at a time high in the forest canopy or "spiked" trees with metal or ceramic spikes that shattered sawmill blades.
In 1994 the Clinton administration implemented the Northwest Forest Plan, which set aside millions of acres to protect the spotted owl and other species that live in old-growth forest lands.
A New Wrinkle
Habitat loss may no longer be the primary threat to spotted owls' survival. "There is a new wrinkle in an old problem," Forsman said. That wrinkle is the invasion of the larger, more aggressive barred owl into spotted owl territory.
"The barred owl either eats [spotted owls], kicks them out of their habitat, or mates with themand sometimes the offspring are fertile," said Steven Courtney, vice president of the Sustainable Ecosystems Institute (SEI) in Portland, Oregon.
These hybrids fall into a legal gray area because northern spotted owls are listed as threatened, while their California cousins are notso they are not protected under the ESA.
Beginning in the 1800s, the barred owl slowly moved north and west from the East Coast. By the 1940s, they had reached British Columbia, and have since moved as far south as San Francisco.
"No one knows if anything can be done to stop the barred owl invasion," said Susan Haig, a wildlife ecologist at the U.S. Geological Survey in Corvallis, Oregon.
"The invasion of barred owls may be the end of spotted owls," Haig said.
Another problem is crossbreeding between two subspecies of spotted owl. Northern and California spotted owl territories overlap in California and southern Oregon, and the birds sometimes interbreed.
These hybrids fall into a legal gray area because northern spotted owls are listed as threatened, while their California cousins are not.
On May 11 of this year, the Center for Biological Diversity, based in Tucson, Arizona, and four other groups filed suit against the U.S. Fish and Wildlife Service for denying ESA protection to the California spotted owl last year.
Why the Continued Decline?
Wildlife biologists don't know exactly what has been responsible for the continued spotted owl declines. Courtney points out that other factors, including major forest fires in the region, may also be heavily impacting their numbersand there are other problems on the horizon.
West Nile virus is high on the list. The virus has recently made its way to the West Coastand has already taken a huge toll on owls in the Eastern U.S. "We expect in the next year it will start causing bird deaths here," Courtney said. "Everyone is very concerned about this new threat." If the virus hits hard, it could lead to huge downward spikes in local populations making a rebound even more difficult.
The results of the new assessment on the status of the northern spotted owl are preliminary. A full report will be released after peer review is complete.
The study was commissioned by an interagency group that monitors the Northwest Forest Plan. It included sightings or captures of 11,432 banded birdsand documented population declines in most of 14 study sites in Northern California, Oregon, and Washington. The report did not specify the cause.
According to the study, the crash was worst in Washington. Spotted owl numbers fell about 7.5 percent a year since 1990 in the state, compared with 2.2 percent in California and 2.8 percent in Oregon.
Overall, declines on federal lands (2.5 percent) were markedly lower than those on state, tribal, and private lands (6.6 percent), which suggest that federal protections may make a difference.
Another report, a five-year status review by SEI will be released soon. The review was demanded by the timber industry to determine whether the owl still deserves federal protection. The Department of the Interior commissioned the report, although no federal scientists were permitted to be part of the assessment team.
Battle Rages On
Meanwhile, the battle rages on in the Northwest. "On any given day you'll find articles in the paper, challenges to logging plans," Courtney said. The Bush administration's recent proposal to place decisions on roadless areas into states' hands could also impact the northern spotted owl, he said.
The administration also wants to increase logging on federal lands.
Timber companies are publicly questioning the logic of protecting forest that spotted owls no longer inhabit.
Some officials think that the Northwest Forest Plan may need to be revised to manage the new threatslike the barred owlthat have emerged in the last decade.
But others feel that sufficient conservation efforts have been made. "We have done about as much as we can to protect spotted owls," Forsman said. "We're seeing two species duke it out. It's too early to tell if they'll survive."
Courtney goes further. "Northern spotted owls are declining rapidlywith a high chance of extinction," he said.
For more owl news, scroll down.
|© 1996-2008 National Geographic Society. All rights reserved.|