Oregon Public Broadcasting

A decade and a half of logging restrictions have failed to halt the slide of the threatened spotted owl. 

Today, the biggest threat to this icon of the timber wars may not be humans as much as an aggressive natural competitor, the barred owl. 

An experiment in the Coast Range west of Eugene is tracking the competition between one set of radio-tagged invaders and the native spotted owls. 

Correspondent Tom Banse reports the study results may raise sticky questions about killing one bird to save another.

LANE COUNTY, Ore. -- Owl researcher David Wiens tracks a radio-tagged spotted owl in Oregonís Coast Range.

It wasn't that long ago that Oregon's Coast Range was fertile ground for the northern spotted owl.

Nowadays, when researchers play recorded spotted owl calls like that one, they rarely get a response.  On the other hand, if you play the calls of a relative newcomer, you'll have better luck.  The prolific barred owl is expanding its range south from Canada. 

David Wiens: "When a pair of barred owls gets very excited, this is what you'll hear. It sounds almost like monkeys calling to each other."

Oregon State University doctoral student David Wiens scans the tree canopy after his battery powered megaphone blares those calls into the woods.  Soon enough, here comes a big, olí owl in search of intruders.

David Wiens: "We call that an eight-note territorial call."

David Wiens knows this bird.  It's one of fifty his team has radio tagged since last year.  Half are barred owls, like this one.  The other half are northern spotted owls. 

Researchers are in the midst of tracking the competition between these owl species for two years.

David Wiens: "There's certainly a lot of interaction going on.  At this point, I would say that we have certain areas where barred owls are having a profound effect on spotted owls."

Six government agencies are paying Wiens to gather solid evidence of what exactly the barred owl is doing to its smaller cousin.

Pretty much 24/7 throughout the year, he or one of his field crew drive the spider web of logging roads with a radio tracking receiver and log book.

Wiens hasn't seen any head-to-head fights to the death.  He does wonder if the more numerous barred owls are eating up the spotted owls' food.  Or if the newcomers are so aggressive, they're driving spotted owls into hiding.

David Wiens: "Some areas I've observed the spotted owls keeping the adjacent barred owls out of their nest area and actually successfully defending their nest areas from barred owls.  Then the question becomes if they're having to spend all their energy keeping the barred owls at bay, then they're not focusing that energy on producing young, which over time becomes a major problem."

This year, out of 16 spotted owl territories in the study area, only one produced young.  The successful nesting pair is the only one that lives unmolested by nearby barred owls.

When it's completed, the study could have lots of implications. 

The timber industry is prepared to argue for opening more land to logging if it's unlikely the spotted owl will come back. 

Environmentalists counter that the arrival of the barred owl means spotted owls need more protected habitat, not less.

Federal owl researcher Bob Anthony says the next logical step is to trap or kill barred owls and see whether the spotted owls bounce back.

Bob Anthony: "Those experimental removals are important because they really are kind of the final test of whether two species compete or not."

The U.S. Fish and Wildlife Service has decided to pursue experimental removal of barred owls.  A team in Portland is working right now to figure out where, when, and how to do that.