Spotted owls disappear from Northwest habitat

Zoom in: Wildlife biologists used listening devices, paired with machine learning, to measure the calls from both species in Oregon, Washington and northern California.

• Across the 2.1 million hours of recordings, barred owls were heard eight times more than spotted owls.
• Of the just over 1,000 sampling areas, spotted owls were detected in 261, while barred owls were present in 891.
• No spotted owls were detected in the Cascades north of Seattle, and the species is "approaching functional extinction thresholds" in Washington and on the Oregon coast.

The findings were published this week in the journal Ecological Applications.

Context: Functional extinction means the owls may be present, but can no longer fill their ecological role or reproduce enough to persist.

Catch up quick: Northern spotted owls became central to the Pacific Northwest's timber wars after they were listed as threatened under the Endangered Species Act in 1990.

• The Northwest Forest Plan, adopted four years later, reduced logging of old-growth habitat on federal lands.

The bottom line: Functional extinction is "not a thing that's happening in the future, it has happened," Damon Lesmeister, a U.S. Forest Service wildlife biologist and coauthor of the study, said in a statement.

• "That doesn't mean we can't do anything. There is still an opportunity for carefully considered management actions."