This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The ever-controversial northern spotted owl (Strix occidentalis caurina) has been protected under the Endangered Species Act since 1990, but despite the best efforts of lawmakers and conservationists the bird's population numbers continue to dwindle. Now the U.S. Fish and Wildlife Service (FWS) has a radical plan to help the raptor: kill some of the barred owls (S. varia) that are outcompeting their spotted cousins for food and habitat.
Spotted owls became notorious following several decades, starting in the 1980s, of back-and-forth lawsuits as environmentalists tried to end logging in the Pacific Northwest's old-growth forests, the habitat the owls depend on for their nests and food. Logging on federal land was banned in 1991, and since then logging in Oregon alone has declined 95 percent, from 4.9 billion board feet of timber in 1988 to just 240 million board feet in 2009, according to The Oregonian. But even with less of its habitat being destroyed the spotted owl population has yet to bounce back.
Aside from its shrinking habitat, the major threat now, according to the FWS, is the growing number of barred owls in the area. These birds are more aggressive, can live in any type of forest, and eat more types of food than spotted owls, making them more adaptable to the current Pacific Northwest landscape.
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According to the FWS's latest draft recovery plan for the spotted owl: "Limited experimental evidence, correlational studies and copious anecdotal information all strongly suggest barred owls compete with spotted owls for nesting sites, roosting sites and food—and possibly predate spotted owls. The threat posed by barred owls to spotted owl recovery is better understood now than when the spotted owl was listed. Because the abundance of barred owls continues to increase, the effectiveness in addressing this threat depends on action as soon as possible."
The recovery plan doesn't spell it out how it would control the barred owl population, but The Oregonian reports that "over the next year, in three or more study areas from Washington [State] to northern California, they might kill 1,200 to 1,500 barred owls."
(This might not actually be quite legal without changing existing laws, as killing any owls is currently against California law under the state's Fish and Game Code. According to the FWS recovery plan, "this statute could hinder the ability to reduce the effects of barred owls on spotted owls in the southern portion of the range.")
It's a tough idea that pleases no one. "There's no winner in that debate," Bob Sallinger, conservation director with the Audubon Society of Portland, told The Oregonian.
The draft recovery plan was released in September 2010. It addresses numerous other threats to spotted owls, including habitat loss, climate change, forest fires and inadequate protective regulations. More than 11,700 public comments have been received on the plan, which the FWS says is expected to be finalized early this year.
Previously in Extinction Countdown: Eagle versus cormorant: What to do when one rare species starts eating another?
Photo: Northern spotted owl, via the U.S. Fish and Wildlife Service