Of Spots and Stripes

By Lee Anna Sherman

To hear Katie Dugger tell it, you’d think catching a baby northern spotted owl (Strix occidentalis caurina) for scientific banding was as easy as taking a Tootsie Roll from a toddler.

“They’re so mellow and laid-back,” the ornithologist says. “If the owl is sitting low enough in a tree, as is often the case, you can just reach up with a tool called a noose pole and peel them off the branch.” Other traits she ascribes to the big-eyed raptors, which she has studied for 13 years, are “gentleness”
and even “charm.”

But the docility that endears these endangered owls to researchers like Dugger and the crew that banded nearly 60 fledglings at Oregon’s H.J. Andrews Experimental Forest this summer is part of what’s threatening their very existence in a landscape of shrinking habitat and intensifying competition for what’s left.

These days, their biggest competitor is the barred owl (Strix varia), a species that’s as aggressive as the spotted owl is placid. A lot less picky about where it lives and what it eats, the barred bird occupies a much wider niche than its narrowly adapted spotted counterpart. Infiltrating territory that spotted owls haven’t had to defend for millennia, they’re finding little resistance.

“Barred owls are generalists, while spotted owls are habitat specialists,” explains Dugger, who is leading studies at six sites across the West as a wildlife biologist with the U.S. Geological Survey and an associate professor at Oregon State University. Spotted owls live only in old-growth forests and eat mostly small rodents, she says. Their bigger barred cousins, on the other hand, willingly feed and breed in a wide range of forest types, including the old-growth ecosystems once dominated by the smaller spotted owl. The diet of these adaptable raptors spans the food web, from insects to amphibians and fish, even crayfish.

“For every spotted owl territory, you can have anywhere from four to eight barred owl territories overlapping the spotted owl territory,” says Dugger, who “inherited” a number of long-term datasets from the late courtesy professor Bob Anthony and co-investigator Eric Forsman of the U.S. Forest Service.

Barred owls are winning — so much so that some researchers are experimenting with “removing” (shooting) barred owls from certain forests where spotted owls once reigned. It’s a bitter irony for wildlife biologists like Dugger. When the spotted owl became the poster species for Oregon’s old-growth wars in the 1980s — pitting timber companies and rural residents against environmentalists and urban naturalists — loggers were locked out of millions of acres of federal forestlands.

Finally, things seemed to be moving in the spotted owl’s direction. But before the environmentalists could even heave a sigh of relief, the barred-owl invasion began. It was a body blow to the owl’s hard-won protection under the federal recovery plan.

The bird’s future is uncertain. “Habitat loss has declined on federal areas,” says Dugger. “Now, federal lands are little islands of good habitat.” But the wider landscape is a matrix, a patchwork of ownership, regulation and wildfire risk that’s hard to assess and even harder to measure. “What I can tell you is,” she adds, “spotted owls are still not doing well.”

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Oregon State ornithologists are carrying out studies from the Oregon coast to the Willamette Valley, Cascade Range, Columbia Plateau and the Zumwalt Prairie. See Avian Nations in the fall 2014 issue of Terra.