September 12, 2004


Owl vs. Owl: A new twist emerges in the turf war over Pacific Northwest forests as a new adversary invades the remaining haunts of the threatened spotted owl. (Sharon Levy, March 1999, Natural History)

Just before dawn, a chill fog drifts through the old-growth redwoods of northwestern California. A group of birders breathe out puffs of steam as they listen to the growing chorus of morning birdsong. Then the gentle sounds of kinglets and thrushes are buried under a torrent of avian rock 'n' roll as the wild, intense hoots of a barred owl ring out. It is one of the first recorded sightings of this species in this part of California. A couple of months later, in May 1997, an agitated barred owl will be found perched near the body of a freshly killed spotted oval in Redwood National Park, near the Oregon border, feathers of his presumed victim stuck in his talons. The latest turf war in the Pacific Northwest has reached redwood country.

Dark-eyed woodland species, the barred owl and spotted owl are cousins that look so similar that novice birders have trouble telling them apart. Until recently, the two birds never met. The barred owl haunted forests east of the Great Plains, while the spotted owl lived only in old conifer forests of the Pacific Northwest. Now the barred owl is on the move--and it is moving in on the threatened spotted owl.

"My educated guess is that the barred owl will have a dramatic effect on the spotted owl," says Eric Forsman, a biologist with the U.S. Forest Service's Pacific Northwest Research Station in Corvallis, Oregon. Twenty years ago, Forsman's research on the northern spotted owl alerted conservationists to the bird's dependence on mature forests, which had Been heavily logged for decades, depleting much of the bird's habitat. This information helped lead to the owl's listing as a threatened species under the federal Endangered Species Act. More recently, Forsman and his colleagues have also been documenting the invasion of the barred owl into the Pacific Northwest.

"For the last thirty years we've been trying to come up with ways of protecting the spotted owl," says Forsman, "and now all of a sudden, this huge monkey wrench gets thrown into the works. In the past, we could assume that what we were seeing in terms of habitat would help us to understand what was happening with the spotted owl. Now we don't know if spotted owls aren't there because there is no habitat for them or because of the barred owls."

"The barred owl is a generalist, so it'll eat almost anything," says Tom Hamer, a consulting biologist who has studied the interaction of the two owls in the northern Cascade Range of Washington State. "It will eat flying squirrels and snowshoe hares, which the spotted owl also eats. But the barred owl will also hunt trout and amphibians in small streams and eat anything else that crosses its path, including grouse." Because the barred owl is such an adaptable hunter, it can live off a home range of only about 1,600 acres in the northern Cascades. But spotted owls of this region are specialists, taking mostly arboreal mammals like flying squirrels and red tree voles. To find enough food to survive, spotted owls need large areas of the older forests that support their prey. In the redwood region (from the Oregon border south to San Francisco Bay), spotted owl home ranges are generally small, because wood rats provide an abundant food source, but in the Cascades, ranges can span 30,900 acres.

During territorial disputes, the owls will hoot at each other (their calls are similar, but the spotted's has a slower, hesitant tempo) and fly at each other, but actual combat seems to be rare. "Barred owls always win," says Hamer. "When it comes to territorial competition, the spotted owl always backs off. Part of it is body size--the barred owl is about 20 percent heavier--but another part of it is behavior. The spotted owl just isn't very aggressive."

How did the barred owl end up on the beleaguered spotted owl's turf? "It's difficult to understand the failure of barred owls to colonize western North America prior to recent times without invoking human influence," says Rocky Gutierrez, a professor at Humboldt State University in Arcata, California. He believes that human tinkering with the western landscape made the barred owl's range expansion possible.

Posted by Orrin Judd at September 12, 2004 9:38 PM

Clearly its George Bush's fault.

Posted by: Robert Schwartz at September 13, 2004 12:28 AM

When environmental groups tried to interfere with her ability to raise cattle (due to alleged protected critters), a ranching client of mine was fond of saying, "Just look at a map of California with the hundreds of thousands of acres of federal and state parkland, open space and timberlands. If the critters can't make it on one-third of this state, its God's way of callin' them home."

Posted by: Fred Jacobsen (San Fran) at September 13, 2004 12:34 AM

This article is 5 years more recent:

Infighting among owls may curtail logging ban
Wednesday, June 23, 2004
Jeff Barnard

LOWELL, Ore. ó It hoots kind of like a northern spotted owl, and it looks kind of like a northern spotted owl.

And like a spotted owl, it swoops in to take a mouse offered on a stick by U.S. Forest Service scientist Eric Forsman in a rainy stand of old-growth Douglas fir in the Willamette National Forest.

However, this is a hybrid ó a cross between a northern spotted owl and a barred owl ó and it a component of the top issue in the review of Endangered Species Act protection for the northern spotted owl, granted in 1990 largely because of loss of its old-growth forest habitat to logging.

The invasion of the barred owl into spotted owl territory, and the subsequent creation of the hybrids, was discussed when a panel of experts met yesterday in Portland with the U.S. Fish and Wildlife Service. The service must make a decision by Nov. 15 on whether to maintain the threatened-species listing for the spotted owl.

The latest studies show the number of spotted owls is declining, though the reason is unclear. Loss of old-growth forest habitat has been minimal, particularly on federal land where logging is restricted. Meanwhile, the barred owl is pushing spotted owls out of the way.

"Clearly the barred owl is having more of an impact on the spotted owl than any of us anticipated 10 years ago," said Jerry Franklin, a University of Washington forest-ecology professor serving on the panel. "The question now has to do with how much that impact is going to be. Is the barred owl essentially going to drive the northern spotted owl out of part of its range?"

The timber industry, which called for the review, argues that if barred owls push spotted owls out of old-growth forests, those stands no longer have to be left standing as habitat.

Conservationists counter that protecting old-growth forests might be more important than ever with the invasion of the barred owl.

"The barred owl was around at the time of the listing," said Susan Ash, conservation director for the Audubon Society of Portland. "Itís reached the radar screen to the point that, yes, itís a new threat.

"But nobody has an explanation for why they have come into the area," Ash said. "This may be some natural process where two species figure out their own roles in the ecosystem."

Posted by: Robert Schwartz at September 13, 2004 3:22 AM

"It's difficult to understand the failure of barred owls to colonize western North America prior to recent times without invoking human influence ..."

True enough, if the only tool at your disposal is post-hoc reasoning.

Posted by: Jeff Guinn at September 13, 2004 7:24 AM

Darwinism is, of course, nothing but a tool of post-hoc reasoning

Posted by: oj at September 13, 2004 7:31 AM

We must reduce human population in the natural Barred Owl habitat and declare open season on the Barred Owl in California. A cleared DMZ type strip between CA and OR might also limit migration and hybridization ... those dirty birds.

Posted by: genecis at September 13, 2004 11:33 AM

>Darwinism is, of course, nothing but a tool of
>post-hoc reasoning

Will you get off your "We Hate Darwin" bandwagon for once? Darwin isn't mentioned in the Gospels; who died and made Anti-Evolution the litmus test of whether you're a Real Christian or not?

It's like those extreme Pentecostals I ran into in my college days; with them "If you don't Speak In Tongues, you're not really Saved!" (And then there's that Pastor Ron filksong "If Your Hair's Too Long, You Can't Be Saved", but that one was a deliberate joke.)

And one Cavalry Chapel pastor down here had a monomanical mad on for Star Wars just as OJ does for Darwin; every radio sermon of his I heard on my car radio, he'd find some way to denounce Star Wars as Satanic, Demonic, Secular Humanist, whatever, no matter how off topic it was or how far he had to stretch.

Posted by: Ken at September 13, 2004 1:09 PM

Ken the choice isn't between Christianity and Darwin, but between Reason and Darwin.

Posted by: oj at September 13, 2004 1:20 PM

Environmentalists imagine that Nature is static, that species never drive out other species. It is almost as if they see their purpose as to preserve the ecological balance of the present as some kind of shrine or museum.

Man has upset the balance, and some species will thrive, while others will fail. It is as simple as that. The Spotted Owl no more deserves to hold onto it's territory in preference over the Barred Owl than GM deserves to hold onto its market share advantage over Ford.

Posted by: Robert Duquette at September 13, 2004 3:34 PM

Between superstition and evidence.

Anyhow, we know enough about population dynamics (though very little in detail, all things considered) to expect that if an organism is expanding its range, it's because some barrier went down.

What barrier in the case of the barred owl?

I've no idea. It could be as subtle as decline of a food species that sustains a predator of barred owls.

Do barred owls have predators? Not many, but not none, either.

On Saturday, my wife and I went down to watch the excavation of a hawksbill turtle nest, helping the last, weakest 36 of about 180 thumb-size turtles make it to the ocean.

Everybody, except me, went away with a feeling of 'mission accomplished.' I took note of the ulua poles a few hundred feet away, where the local guys were nightfishing from the beach for jack crevalle. Nothing an ulua likes better than tender, tasty baby turtle.

Orrin ridicules Malthus, but that's because he's a city boy. If he was a hunter, he'd change his tune.

Posted by: Harry Eagar at September 13, 2004 3:41 PM

I think one problem is one of titles.

We could have saved ourselves a bunch of postmodernist nonsense if Einstein had decided on Theory of Invariance instead of Theory of Relativity.

And if Darwin had named his book Extinction of Species.

The cause of the barred owl encroachment is as yet unknown, but it is also irrelevant. It could just as easily be an increase in food sources (remember a thread of several months ago noting how animals were reestablishing themselves in populated areas) leading to more barred owls. But it doesn't matter. The owls are doing what owls do, and the barred owls in the Olympia forest have not the tiniest notion of what is going on anywhere else.

Evolution is happening right before our eyes, and it involves a dimension heretofore completely outside OJ's Malthusian obsession: space.

One species is more adept at getting it than another. If that trend continues long enough, the latter will cease to exist.

No plan. No planner. Just statistics and time operating precisely as Darwin supposed.

Posted by: Jeff Guinn at September 14, 2004 7:12 AM

It was caused by us, as have they mostly been--the exception being those caused by catastrophic events. They're never caused by natural selection.

Posted by: oj at September 14, 2004 7:27 AM


You have gone off the rails on this one--there are several explanations fitting the facts as well as human induced habitat change. And there is no reason--other than resorting to pure post hoc reasoning--to reject the others.

Since roughly 99% of all the species that ever existed were extinct prior to humanity, how do you explain the substantial portion of that number occurring without any connection to catastrophic events?

Posted by: Jeff Guinn at September 14, 2004 12:11 PM

What are the others?

Posted by: oj at September 14, 2004 12:17 PM

Favorable conditions causing an increase in the barred owl population.

Long ongoing encroachment of barred owls upon spotted owl territory, which had, by the time humans showed up, restricted the spotted owls range to the Olympic Forest.

Posted by: Jeff Guinn at September 14, 2004 2:57 PM

At which point we forced the barred owls into spotted owl territory. Extinction by intelligent design...again.

Posted by: oj at September 14, 2004 3:08 PM


Come now. Both reasons I cited have nothing to do with "forcing" barred owls into spotted owl territory.

Unless you can demonstrate it is not a phenomena that has been going on for thousands of years, or that the population of barred owls has not been increasing, then you can't possibly arrive at your conclusion.

I'm not surprised, though. Your lack of intellectual rigor on this subject has never been more glaring than now.

Posted by: Jeff Guinn at September 14, 2004 8:55 PM


As you point out the spotted owl had the old growth forest.

Posted by: oj at September 14, 2004 9:54 PM


The spotted owl didn't "have" the old growth forest. Old growth forest is its remaining range, very likely due to population dynamics long preceding, and having nothing to do with, humans.

"Unless you can demonstrate it is not a phenomena that has been going on for thousands of years, or that the population of barred owls has not been increasing, then you can't possibly arrive at your conclusion."

Posted by: Jeff Guinn at September 15, 2004 7:06 AM

When we got there it was there, now it's not. We Heisenberged it, if nothing else.

Posted by: oj at September 15, 2004 7:23 AM

Classic post hoc fallacy, and once again misstating the Heisenberg principle.

In terms of the Heisenberg principle, what constitutes observation?

Posted by: Jeff Guinn at September 15, 2004 10:42 AM

All we have is post hoc because nothing ever evolves in front of us. We start with a result and reason backwards.

All observation shapes reality.

Posted by: oj at September 15, 2004 11:06 AM

Owls are evolving right in front of you.

"In terms of the Heisenberg principle, what constitutes observation?"

"All observation shapes reality."

Just like a politician. You answer the question you wanted to hear, not the one asked.

Posted by: Jeff Guinn at September 15, 2004 1:57 PM


Exactly--we drive evolution.

Observation = observation

Posted by: oj at September 15, 2004 2:04 PM

Well, Orrin, any extinction observed by humans is also likely to have been impacted, in some fashion, by humans.

But there's a mountain (literally) of evidence about extinctions that could not have been influenced by humans, and as we can observe how natural selection works on two populations brought into contact by humans, we can confidently expect that two species brought into contact by any non-human agency would work about the same.

The big example would be the raising of Central America, followed by extinctions and difffusions of species both north and south.

Generally, the more advanced mammals did better, but not in every case.

That's evolution for you. You cannot predict, you must observe.

Posted by: Harry Eagar at September 15, 2004 3:13 PM


There you go--humans or catastrophic events, not gradualism. No one's arguing against evolution, just that Darwinism can't cause it.

Posted by: oj at September 15, 2004 3:17 PM


Your terming the raising of Central American catastrophic is among the most specious things I have ever heard.

What, do you think the Andes arose overnight? If they rose at a foot a year, it would still have taken 14,000 years.

Please explain how that is not gradual.

Darwinism is a very coherent explanation for extinctions, and is utterly appropriate for this circumstance. The original cause of the competition is irrelevant to how the competition proceeds--whether volcanoe, desertification, continental collision or subdivisions, it just doesn't matter.

"Observation = observation"

Wrong. Dead wrong. Until you can figure out why that is so wrong, perhaps you'd be better served by not imitating postmodernists in their abuse of concepts they do not understand.

Posted by: Jeff Guinn at September 15, 2004 8:14 PM
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