EnlargeA scene that may become more familiar: Barred owls killed in a northern California management experiment bear silent witness to a tough choice. California Academy of SciencesShould Oregon shoot barred owls to save spotted owls? gallery (7 photos)
Come summer, federal wildlife officials expect to finish a draft environmental impact statement that most likely recommends taking to the woods with shotguns. Over the next year, in three or more study areas from Washington to northern California, they might kill 1,200 to 1,500 barred owls -- the larger, more aggressive competitor that has routed spotted owls from much of their territory and become, along with habitat loss, the biggest threat to their survival.
It's a wrenching decision that splits wildlife biologists and environmentalists. Killing one native animal to benefit another -- especially a "big, beautiful raptor, a fantastic bird," as one biologist puts it -- is such a leap that the U.S. Fish and Wildlife Service hired an environmental ethicist to guide its discussions.
"There's no winner in that debate," says Bob Sallinger, conservation director with the Portland Audubon Society.
Some biologists believe the proposal won't work. More barred owls, perhaps hundreds, would have to be killed every year to keep the study areas free of interlopers for three to 10 years. One biologist estimated the cost at up to $1 million annually.
Others oppose intervening in what they see as natural selection at work.
"Population dynamics between two native species should not be artificially manipulated," says Blake Murden, wildlife and fisheries director for Port Blakely Tree Farms in Tumwater, Wash.The company is not anti-owl. In 2009 it agreed to manage 45,000 acres as spotted owl habitat in exchange for protection from additional logging restrictions.
Murden says barred owls expanded rapidly because they adapt well to mixed habitat and eat a variety of prey, while spotted owls prefer old-growth to nest and, in most of its range, flying squirrels to eat.
"It's a generalist and a specialist," Murden says, "and invariably the generalist will win."
Spotted owl vs. barred owl
Northern spotted owl
Strix occidentalis caurina
Strix occidentalis caurina
Size: 16 to 19 inches tall, up to 48-inch wingspan, weighs 1 to 2 pounds
Appearance: Medium size, brown with white spots; round-headed, no ear tufts
Life span: 10 to 20 years
Range: British Columbia to Northern California
Habitat: Mature and old-growth forests
Prey: Primarily flying squirrels and tree voles, more varied at southern end of its range
Reproduction: Mating season February or March, two or three eggs in nest
Personality: Curious, associates human researchers with food
Status: Population declining by 3 percent annually; listed since 1990 as threatened under the U.S. Endangered Species Act because of habitat loss, now losing territory to barred owls
Barred owl
Strix varia
Size: 17 to 20 inches tall, 40- to 50-inch wingspan, weighs 1 to 2 pounds.
Appearance: Medium size, brown with white horizontal bars on the chest and white vertical bars on the belly; round-headed, no ear tufts
Life span: 10 to 20 years
Range: Originally from East Coast, spread westward across U.S. and Canada, now found throughout the spotted owl's range
Habitat: Prefers old growth in the Northwest, but highly adaptable; lives in temperate rain forests, wooded swamps, even city parks
Prey: Wide variety of rodents and small mammals
Reproduction: Breeds March through August, lays two to four eggs
Personality: Aggressive, territorial, wary; known in the East as a "hoot owl" because of distinctive call characterized as "Who cooks for you, who cooks for you all"
Status: Expanded rapidly over past 20 years
The biologist who carried out the experiment cautions the results may not apply everywhere. Owl habitat and prey in Oregon and Washington are quite different, says Lowell Diller, with Green Diamond Resource Co., which owns 400,000 acres of timber adjacent to Redwood National Park.
He nonetheless concludes barred owls can be controlled. Choosing to do so, however, is "looming as one of the biggest conservation dilemmas we have faced in the Northwest."
The spotted owl is a conservation icon. Its 1990 listing as threatened under the U.S. Endangered Species Act was the first to have such broad economic, social and environmental impact.
"We have a huge amount of resources committed to protecting that species," Diller says. "Then we have the barred owl show up."
Down in timber country, Douglas CountyCommissioner Doug Robertson calls the proposal to shoot barred owls an example of "dysfunctional" forest policy. Counties like his depend economically on federal timber, which Robertson says is managed to benefit a species that can't be recovered.
"When nature takes a turn, it's going to prevail no matter what we try to do," he says. "I've come to the conclusion that it's nonsense to shoot one species to benefit another. I don't think the public will accept it."
***
We've intervened before. The freshest local example -- currently halted by a federal appeals court -- is the killing of more than three dozen California sea lions at Bonneville Dam in the Columbia River because they devour thousands of salmon.
Federal agents moved or killed cormorants and terns that feed on juvenile salmon and steelhead in the Columbia. Oregon offers a bounty on northern pike minnows, which also eat young salmon. Elsewhere, Texas landowners kill or trap cowbirds because they invade the nests of smaller songbirds.
But shooting barred owls is a different story. Those against it argue they are a native, not an invasive species, and their threat to spotted owls is due to range expansion and competition.
Some biologists believe barred owls and spotted owls were the same species before diverting into East and West Coast versions, respectively, during the Ice Age. Spotted owls are about 18 inches tall and weigh slightly more than a pound. Barred owls are somewhat larger. The two have interbred in some cases and produced fertile offspring.
At first, barred owls slowly advanced westward with settlers. Barred owls were in Montana by 1909, British Columbia by 1943, Washington state in 1965 and Oregon in 1972.
Population statistics aren't available, but biologists agree the Northwest's barred owl numbers exploded in the past 20 years. Diller, the Green Diamond biologist, believes they either reached a population tipping point or fully adapted to West Coast conditions and became "kind of a super owl."
"They just do everything well," he says.
Spotted owls don't. They've been on the ropes for decades due to heavy logging of old-growth forests. A 1990 report estimated spotted owl habitat had been reduced 60 percent to 88 percent since the early 1800s.
The decrease in logging has been equally sharp. In 1988, Oregon loggers cut 4.9 billion board feet of timber on federal land. The 2009 federal harvest was 240 million board feet.
Logging reductions undoubtedly saved habitat, but the bird itself hasn't shown signs of recovering. Spotted owl population estimates are vague, but studies indicate it declines 3 percent annually in much of its range. Some scientists estimate that a couple thousand mating pairs remain, and leave it at that.
Biologists knew as early as 2004 that barred owls were displacing spotted owls. A report that year warned of their "negative impact," and a 2006 report labeled barred owls among the "most pressing threats" to spotted owls.
The 2010 spotted owl recovery plan, to be released in mid-February, concludes "barred owl removal should be initiated as soon as possible." Meanwhile, a fish and wildlife service work group is drafting a parallel environmental impact statement on killing barred owls. It will be finished by early summer.
Conservation groups are waiting to see the statement before committing, but begrudgingly acknowledge they may support barred owl removal on an experimental basis.
"We certainly don't want barred owls killed, but the highest priority has to be placed on not having spotted owls go extinct," says Sallinger, with the Portland Audubon Society.
He argues logging weakened spotted owls to the point barred owls could expand rapidly. Amending habitat loss is the first step in rebalancing the playing field, he says.
"Going out and killing barred owls, if you haven't taken the other necessary steps, would be really horrific."
***
Last October, biologist Robin Bown and others from the federal barred owl work group accompanied Green Diamond biologist Lowell Diller into the forest. It was near dusk, on a ridge where Diller had seen a territorial barred owl a few days before. He played a recording of a barred owl call, and within a few minutes the targeted bird flew in to investigate.
Diller made sure the area was clear, took aim with a shotgun and blasted the owl from its perch. It was a clean kill, instantaneous.
Diller has a scientific collection permit to shoot barred owls. He and another biologist killed 20 in 2006 and 20 more in 2009. Last summer, he secured a permit to kill up to 70 more over three years in the study area.
The company has a government-approved conservation plan that avoids additional regulations if they maintain habitat for spotted owl.
"The success of that plan depends on us having spotted owls occupy our landscape and utilize our habitat," Diller says. "If barred owls preclude them from using it, then our plan is going to fail."
At one time, Green Diamond had more than 150 spotted owl nesting sites, and biologists saw barred owls perhaps once a year. Now, barred owls appear every time Diller turns on his recorded owl calls.
"They are taking over," he says.
Barred owls' aggression is their Achilles heel, Diller says. When they hear another owl calling -- barred or spotted -- they fly to confront the intruder. Less wary than usual, they are easy targets.
You don't have to kill them all, he says. A measured reduction in their numbers -- 10 to 20 percent -- might be enough to allow the two species to coexist.
"The worst thing would be to spend millions, kill a bunch of barred owls, and get no treatment effect."
But it's a tough business. Diller says he couldn't watch when he went out the first time in 2006, with the other biologist wielding the shotgun.
"It's not something you do casually," he says.
As leader of the fish and wildlife service's work group, Bown believes it was important for team members to see firsthand what they may endorse. They recovered the owl Diller shot and packed it off for study.
Bown also believes a "positive response" by spotted owls is very likely. Federal wildlife managers, she says, have a mandate under the Endangered Species Act to give deference to spotted owls.
That doesn't make the decision easy.
"It's values and ethics," she says, "and how we look at the world."
--Eric Mortenson
Bob Zybach's comment:
This is strictly a political argument, not (necessarily) a scientific
one. The whole listing of spotted owls as an "endangered species" in
the first place seems suspect -- except as a method of using the ESA
to stop logging on federal lands, thereby crippling rural businesses,
families, communities, and counties for decades. Who benefits?
Spotted owl numbers continue to go down, so they haven't. Rural
counties are now on federal relief programs in order to maintain basic
operations, and many county residents have also become dependent on
federal programs, rather than helping to fund them as in times past.
Environmental organizations and their lawyers certainly benefit.
Probably a lot of urban politicians, too. Conspiracy theorists might
postulate Weyerhaeuser, Georgia-Pacific, and other Big Business
operators that have their own timberlands and manufacturing facilities
are also beneficiaries. "Wildland" firefighters are another group.
But certainly not rural residents or American taxpayers -- or spotted
owls.
It is probably politically incorrect to do so, but I think it is
helpful to look at the assumptions of agency-based wildlife science as
if they applied to humans as well. If we attempted to estimate
current human populations of Detroit based on "habitat" (homes and
apartments), would we get an accurate figure? Or would all the empty
buildings give us a different number than say, Tokyo or Mexico City?
If we went to Detroit and built more homes would the population (other
than the temporary population of builders and related operators)
increase? For what reason(s)? Because of more "available habitat?"
And who -- exactly -- determined which kind of habitat is preferred
(nee "required") by spotted owls in the first place? Were their
assertions ever allowed to be challenged by knowledgeable skeptics
(and if so -- who -- exactly)? Maybe its mostly a food problem or a
virility problem or a predator problem, or all of the above, and has
little, if anything, to do with habitat at all. Where is the real
science (actual observation and documentation and analysis) in this
modeling exercise? Results are certainly not what was predicted when
the agencies chose to shut down active management of our federal lands
in deference to "the best science available." Time for an objective,
thorough, scientific, review of these assumptions; or better just to
start shooting barred owls for messing with the scientists and their
highly expensive conjectures?
Are numbers of northwest spotted owls actually less than 200 years
ago? Based on what? Assumed habitat configurations? The barred owl
came into the PNW during most of our lifetimes and quickly filled, and
expanded, the range of spotted owls in less than 20 years. Spotted
owls fly, too. They were first noted in California in the mid-1800s,
in Washington durjng the late 1800s, and in Oregon in the early
1900s. Could their local populations have actually increased between
1850 and 1950? Historical evidence and barred owl demographics would
certainly seem to support that hypothesis. Another problem is that
there was significantly less forest biomass 200 years ago than today.
If it is really a habitat problem, shouldn't we be reducing increased
biomass (and thereby reducing risk of catastrophic wildfire, too),
instead of letting it increase (and burn)?
Even more disturbing is the fact that barred owls (in the east they
are called "hoot owls) have been successfully breeding and producing
viable offspring with spotted hoot owls. Are they really a separate
species? To use the human analogy again, there are much greater
differences in size, physiology, coloring, vocalizations, diets, and
preferred habitats between Swedes and Pygmies than between barred hoot
owls and spotted hoot owls -- yet we say that both Pygmies and Swedes
are the same species, and that that species -- Homo sapiens -- is
certainly not "endangered."
The same arguments hold true for gray wolves, murrelets, and salmon.
I think it is past time to reexamine the "science" that created or
justified these problems in the first place, rather than letting a
bunch of wildlife biologists loose with loaded weapons -- and at
taxpayer expense. Two wrongs rarely make a right.
One man's opinion, anyway.
From Ralph Saperstein:
The financial impact on the large corporate forest landowners has not
provided any environmental or rural community benefit: The lack of
federal timber led to a substantial increase in the value of private
forest land. This increased value completely reformulated the forest
products industry as companies were forced by their shareholders to
spin off their forest land to TIMOs, REITs and various other non-
manufacturing entities. The federal tax structure has encourage this
divestment. The environmentalists have now created a Forest Products
Industry no one can be proud of.
Ironically, the USFWS's Spotted owl Recovery Plan wants to preserve
all habitat, their definition, on private forest land. Meanwhile,
rural communities and in a close race with the Spotted owl toward
extinction...
No comments:
Post a Comment